Guide to Extending Your Home

7/27/2019 Guide to Extending Your Home

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Guide to Extendingyour Home

A Ten Alps Publication


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CLI VE WOODWARDCLI VE WOODWARDb u i l d i n g s e r v i c e sb u i l d i n g s e r v i c e s

Building Work

Carpentry

Refurbishment

Extensions

Roofing

t . 0 1 8 6 5 3 6 1 7 2 5

m . 0 7 7 1 1 6 5 6 2 3 7

Low er Fa rm, Low er Roa d,

G a rs ing ton, Oxford OX44 9DP

Fascias Soffits Bargeboard

Claddings Window Boards Interior Trims Foiled Pro files

We also supply products for the following:

Gutters Drainpipes

Drainage Window Ancillaries Conservatory Roofing

A Walker UPVC LimitedRadley Road Industrial Estate, AbingdonOxfordshire OX14 3SB

Tel: 01235 537590 Fax: 01235 537591

ww w.awalkerupvc.com Email: sales@ awalkerupvc.com

A. WALKER

UPVC LTD.

CHILTON WASTE SERVICES

01235 831913

www.chiltonwasteservices.co.uk

One c all away from a fast,

pro fessional service

Skip Hire Roll-on-off Containers Grab & Delivery Service

Crushed Hardcore Screened Soil and Wood Chippings

Licensed Tipping Recycling

Waste Transfer and Inert Landfill

weprovide..

.

wesell...

wedo

...

Tim WiddowsonPerspective Artist Painter

Architectural and Interior Visualisation

Landscapes

Mallard Reach, High Street, Long Wittenham,Oxon OX14 4QQ

Tel: 01865 407757 [email protected]


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South Oxfordshire & Vale of White Horse Guide to Extending Your Home 1

Contents

3 Introduction11 Domestic Extensions25 Loft Conversions34 Garage Conversions39 Domestic Cellar Conversions43 Other Alterations46 Radon

This publication is available as an E-book: www.extendingyourhome.com/valeofwhitehorse


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2 South Oxfordshire & Vale of White Horse Guide to Extending Your Home


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Background

Your home is likely to beone of your biggest assets,it is a major long-terminvestment and over thecourse of your occupancyyour home will have to

adapt to the changing needsof you and your family.

Within England and Walesmost construction work iscovered by the BuildingRegulations. These areminimum technicalstandards set by thegovernment and all but the

most minor building workcarried out must conform tothese standards.

The standards cover manyaspects of health and safetywithin buildings as well asenergy consumption andaccessibility. The BuildingRegulations are detailedtechnical standards set to

ensure that the buildingstock within England andWales is built to areasonable standard andthat it meets the needs ofthe population.

The Building Regulationsare minimum standards,they do not cover quality of

workmanship beyond thatrequired to ensure the basicsafe construction of thebuilding. It is possible

therefore that a buildingwhich complies with theBuilding Regulations maynot meet the finishingstandards that you requireand you should be mindfulof this when you are

entering into contractualarrangements with yourbuilder.

There is a legal requirementon both the builder and theowner of the building tomake an appropriateBuilding RegulationsApplication and to complywith the BuildingRegulations. Failure to do socan result in prosecutionthrough the MagistratesCourt.

Purpose of this Guide

This guide will take youthrough the BuildingControl process.

It is not a substitute forprofessional advice but itaims to show how yourproject will be affected bythe Building Regulations.The guide is divided intochapters that contain adviceabout typical buildingprojects and it is hoped thatwhen you have read the

guide you will have a betterunderstanding of what isinvolved in a domesticbuilding project.

Introduction

South Oxfordshire & Vale of White Horse Guide to Extending Your Home3


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Br i ckw ork con t rac to rs

A&D Construction and Sons Ltd. are a Swindon based, famil y managed business specialisi ng inbrickwork and scaffolding services to house bui lders, com mercial developers and privateindividuals.

Establi shed in 1997 by Anthony Humphreys from a single bri cklaying team, A& D Constructionhave grown consistently over the years.

With over 80 bricklayers and stonemasons employedA&D Construction work with cli ents such as TaylorWimpey Oxfordshire, Taylor Wimpey Bristol, NorwestHolst Limited, ISG Pearce, McClaren, David WilsonHomes (Southern). We have also recently com pletedlarge comm ercial projects such as CirencesterLeisure Centre and the B& Q Superstore at Barnfield ,Swindon and the im pressive mixed use developm entfor Norwest Holst in Winchester.

At A& D Construction our reputation for excellenceand integrity and quality workmanship i s extremelyim portant to us. As a truly fami ly run business (withAnthony and wife Dawn heading the business, plusfour sons and their wives and partners involved) it isdefini tely a matter of famil y pride! As a result of ourfocus on attention to detail we have won numerousBrickwork awards.

In 2001 we introduced a scaffolding service into ourbusiness to provide our clients with a single poi nt ofcontact for both project elements leading to improved coordination and programm ing and greaterproject efficiency. Click A& D Scaffolding for more details. Our scaffolding service can work jointlywith our bricklaying division or can be c ontracted separately if required.

A&D Scaffolding

Supplying Scaffolding for : Single house builds

S ma ll/spe cia lis t hous ing

developments

La rg e hous ing

de velopment projec ts

Commercia l, industria l

and retail developments

Local Authority projects

Tel /Fax: 017 93 78 31 90

Emai l: enquir ies@ aanddconstructi on.co.uk www.aanddconstruction.co.uk

A&D Const ruc t ion & Sons LT DPe nnyhooks Farmhouse, S hrivenham, Nr Swindon S N6 8EX


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Domestic projects thatmay require BuildingRegulations consentinclude:-

Extensions

Garage conversions

Loft conversions

Cellar conversions

Structural alterations e.g.removing load bearingwalls

Alterations to drainage,hot water or heating

systems New or replacement

windows

Electrical work

Replacement roofcoverings

Cavity wall insulation

Some garages

Some conservatories

If you are considering abuilding project and you areunsure as to whether it willrequire Building Regulations

consent please feel free tocontact us and we will behappy to advise you.

The BuildingRegulations Process

If your project needsBuilding Regulationsconsent you will need tomake a BuildingRegulations application.

How to Proceed

Unless you are experiencedin construction you willneed to get some

professional advice. Thereare a number of ways ofobtaining this including:

1. Appointing an architect/technician or buildingsurveyor: these willprepare drawings anddesigns for yourproposal, obtain the

necessary approvals andif required they will alsohelp you to find asuitable builder andmanage the projectfor you.

2. Appointing a design &build company: thesecompanies offer a onestop shop forconstruction projects,their design department

will prepare thenecessary drawings andobtain the necessaryapprovals and theirconstructiondepartments willtranslate these drawingsinto reality.

3. Using an experienced

builder: some buildershave experience incarrying out domesticprojects and may beable to offer you apackage similar to thedesign & buildcompanies.

Making a Building

RegulationsApplication

There are two ways ofmaking a BuildingRegulations application:-

Full Plans Application

This is often thought of asthe traditional way ofapplying for BuildingRegulations Approval. Thebuilding designer will drawup detailed plans andsupporting information forthe proposed scheme andwill send them to ustogether with an applicationform and the necessary fee.We will then check the

details and following anynecessary consultations andliaisons with the buildingdesigner a Building



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Regulations Approval willbe issued.

Work can start any timeafter the application hasbeen received although it iswise to wait until the

scheme has had its initialcheck under the BuildingRegulations, this usuallytakes between two andthree weeks.

Our team of surveyors willliaise with your builder andinspect the work in progresson site. When the project is

satisfactorily completed aBuilding RegulationsCompletion Certificate willbe issued showing that theproject has beenindependently inspectedand that it complied withthe Building Regulations.

Building Notice

ApplicationThis system is best suited tosmall projects carried out bya competent builder and isnot recommended unlessyour builder and designerare very experienced in thetype of project that you areundertaking and are fullyaware of the requirements

of the Building Regulations.Under this scheme noformal Approval of plans isissued and work is approvedon site as it progresses.

To use the Building Noticeprocess you or your agentwill need to submit aBuilding Notice applicationform together with a sitelocation plan and therequired fee. Work can

commence 48 hours afterthe notice has beenaccepted.

When work commences oneof our surveyors will meetwith your builder to discuss

your intentions, to agreehow the work should becarried out, agree when thework will need to beinspected and to establishwhether any furtherinformation will be requirede.g. structural calculationsor drawings.

When the project issatisfactorily completed aBuilding RegulationsCompletion Certificate willbe issued showing that theproject has beenindependently inspectedand that it complied withthe Building Regulations.

The forms for making a

Building Regulationsapplication can be obtainedby telephoning or calling intoour offices, or can bedownloaded from our websitewww.whitehorsedc.gov.uk

Self Certification

To help you to gain BuildingRegulations approval more

easily the government haveallowed certain trade bodiesto self certify theirmembers work and to issueBuilding Regulationscertificates. Currently thebodies which can issuethese certificates are:-

1. FENSA Contractorsregistered with FENSAcan issue certificates forreplacement windows.

2. CERTASS Contractorsregistered with CERTASScan issue certificates forreplacement windows.

3. GAS SAFE Registeredcontractors can issue

certificates forinstallations andalterations to gas, hotwater and heatingsystems so long as thecontractor is aregistered installer andnot just a serviceengineer.

4. OFTEC RegisteredOFTEC installers canissue certificates forinstallation of andalteration to oil burningboilers and appliances.

5. HETAS RegisteredHETAS installers canissue certificates forinstallation of andalteration to solid fuelburning boilers andappliances.

6. Part P ElectricalContractors registeredunder one of the Part Pschemes can issuecertificates for domesticelectrical work.

Tips for using SelfCertified Contractors

1. Always ensure thecontractor is registeredfor the work they areundertaking, eg. If youare having a newheating system installedensure the contractor isa registered installer nota service engineer.


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D.

E.R. LO

NGD.

E.R. LO

NG& SON& SONB u i l d er & D eco r a t o r

Groundwork Extensions

Roofing Brickwork

Plastering & Rendering Carpentry

Patio Design Wood Decking

Interna l & External Dec oration

Oxford

739657

Mobile

07860 866329

Oxford

739657

Mobile

07860 866329

Al l Enquiries Welcome

Firm Quotati ons Given On Request

Fax: 01865 739657

18 Sandleigh Road, Dry Sandford,

Nr. Abingdon, Oxon OX13 6DP


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2. Always ensure that atthe end of the job thecontractor issues youwith a Certificateconfirming that the workcomplies with the

Building Regulations,you may need this whenyou come to sell yourproperty.

3. If you are in any doubtabout anything eithercontact the relevanttrade association orcontact Vale of WhiteHorse Building Controlfor advice.

Other Permissions youmay Require

Planning Permission: manydomestic alterations will alsorequire Planning Permission,further advice is availablefrom the Planning Portal

www.planningportal.gov.ukor to confirm whetherPlanning Permission will berequired for your projectplease either contact one ofour Planning Officers on:North Team 01235 540347,South Team 01235 540348or download and complete

the householder enquiryform from our websitewww.whitehorsedc.gov.uk

Party Wall Act: if yourproposal affects a Party Wallor if you will need to

excavate foundations closeto your neighbours houseyou may need to give themnotice under the Party WallAct. This is a Civil Act andVale of White Horse DistrictCouncil do not have anyenforcing power under theAct. Further details of thiscan be found on thePlanning Portalwww.planningportal.gov.ukor contact us for the latestguide to the Party Wall Act.

The InspectionProcess

Whatever type of projectthat you are undertaking we

will arrange to carry out aseries of inspections of thework in progress. Whilst wecannot be on site all of thetime the inspections will becarried out at key stages sothat we can be reasonablysure that the work carriedout complies with the

Building Regulations.We will tailor theinspections carried out tosuit your individual projectand we will generallyarrange these inspections

with your builder. If duringthe project you have anyconcerns, if you wantsomething specificinspecting, or if you wouldlike to meet to discuss anyissues please contact usand we will make thenecessary arrangements.

CompletionCertificates

When your project has beensatisfactorily completedunder the BuildingRegulations we will issue aCompletion Certificate. Thisis a legal document that youwill need if you want to sell

your house, you may alsoneed it for re-mortgaging orinsurance purposes.Please ensure that we arecalled in to carry out ourfinal inspection at the endof the project to ensure thatyour Completion Certificateis issued.


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Domestic

ExtensionsIntroduction: if you needmore space and you do notwant to move house youmay wish to considerextending your home. Yourhome is probably your mostvaluable asset so it is

important that yourextension project iscarefully planned. Thisguide is not a substitute forprofessional advice but hasbeen written to provide you

with useful information

about how the Building

Regulations will affect

your extension.

Suitability: most houses are

suitable for extending,

providing that you have the

space. When you are

thinking about whether your

house is suitable for

extending you might like to

consider:


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Wiltshire Woodworking is a com pany specialising in dom estic carpentry and joinery but also working withinthe com mercial and industrial sector throughout Oxfordshire and the surrounding counties.

Wiltshire Woodworking has developed soli d custom er relationships, providing q uality workmanship by aqualified and experienced carpenter and joiner. Please take time to look at the gallery page on our website

where you can view a small selection of j obs undertaken by Wiltshire Woodworking.

If you require more information, or wish to request a free no obligation quote, please dont hesitatein contacting us.

Broad Street , Uf f ington, Oxfordshire, SN7 7RA0 7 7 7 1 9 5 3 8 0 3 0 1 3 6 7 8 2 0 4 6 2 j a m ie @wi l t sh ir e wo od wo r k i ng .co . uk

Glenn Whi t eCarpentry & Building

7 Hobbyhorse Lane, Sutton C ourtenay

Abingdon, O xfordshire O X14 4BB

Tel: 07934 617250 Email: glennwhite@ hotmail.co.uk

Wiltshire WoodworkingDom estic a nd Comm ercia l Ca rpent ry & Joinery


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1. How will you accessyour extension?

2. What effect will yourextension have on thecirculation in andaround your home?

3. What effect will yourextension have on yourexisting house andgarden? Will it block out

light from existingrooms or make somerooms unusable? Willyou still be able to getinto your garden?

4. Is your existing housebuilt from an unusualconstruction forexample prefabricatedpanels, concrete frameetc?

If you can resolve all ofthese issues then your

house may well be suitablefor extending.

How to Proceed: extensionsare complex projects andunless you are experiencedin construction you will

need to get someprofessional advice. Theintroduction containedadvice about obtaining thisand with this in place wecan now consider some of

the technical issues thataffect domestic extensions.

Technical Issues

Foundations: thefoundations are one of themost important parts ofyour extension and oftenone of the most expensive.For domestic extensionstrenchfill foundations arethe most common, theseshould be taken down intofirm natural ground andshould generally be aminimum of 1m deep. Inareas with clay subsoil treesup to 20m away can have asignificant effect on

foundations which generallymeans that they need to bedeeper, sometimes as deepas 2.5m. If you areconcerned about any trees

Certain ground conditions will affect the ground floor detail



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Electrical Test & Certification Re-wires Part or Complete

Electrical Showers Complete Portable Appliance Testing

Extra Power or Lighting Points

Fire Intruder Alarms

J .M.Const ruc t ion

13 Cherry Tree Road, Chinnor, Oxfordshire OX39 4QYTel/Fax: 01884 353888 Email: [email protected]


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please get in touch with usand we will give you someadvice regarding foundationdepths.

Ground Floor: the groundfloor of your extensionperforms a number of tasks:it must support the floorloading, keep out damp andprovide thermal insulation.Generally a ground floor is amultilayer structure, the topsoil under the extensionfloor area is removed and a

layer of compacted stone isplaced over the site. This isblinded with sand and alayer of 1200g polythene isthen placed over the sandand lapped in with thedamp proof course in thewall (in certain areas,especially in the north andwest of the County, it may

be necessary to protect thedevelopment from radon, anaturally occurring radioactive gas, by the

installation of a suitablemembrane at floor level.With the closure of manymines in the south eastSTYTHE gas and Methaneprotection will also berequired, as a 1200gpolythene barrier will notprovide adequateprotection, if in doubtcontact your local areaoffice). A layer of insulationis then provided and aconcrete slab at least

100mm thick is poured overthe insulation.The concrete can either befloat finished or a screedapplied at a later date. Onsome sites where theground floor is significantlyhigher than external groundlevel or where the site hasbeen affected by trees, a

suspended floor may beneeded, these can beformed from either concreteor timber and if you need

any guidance regardingsuspended floors, pleaseget in touch with us foradvice.

Walls: the walls of yourextension must carry theloads from the floors androof, keep the weather outof the extension and providethermal insulation. Cavitywalls are commonly usedfor domestic extensions.These are made up frombricks and blocks and the

cavity is filled withinsulation as the workproceeds. When buildingwalls remember to ensurethat you have adequatebuttressing at the corner ofyour extension, lintels overall openings, wall ties tojoin the leaves of your cavitywall together and a suitable

damp proof course. If youare building up against yourneighbours house you willalso need to ensure that


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Peewit Farm95 Drayton Road

Sutton Courtenay, AbingdonOxfordshire OX14 4HBTel: 01235 531238

Email: [email protected]

Glenbury

Construction

Rober t

HamletBuilders

17 Ma nor Fa rm Roa d

Horspath, Oxford

OX33 1SD

E: rob ertha mlet@ hotmail.co .uk

Tel:0 1 8 6 5

8 7 2 8 7 0

DAVID COOKSLEY

ASSOCIATES

Architects & Project M anagers

Bui ldin g plans drawn an d local authority

consents sought for :

Extensions & Alterations

Individual Houses

Conversions

Refurbishments

Commercial

Listed Bui ldings

Town Planning Consultants

D esign & Bui ld Project Co-ordination

Expert Witness

Excel Studios

24A Gatehampton RoadGoring-on-Thames,Reading RG8 0EP

Tel/Fax: 01491 872306Mobile: 07789 938291Email: [email protected]

Abingdon-on-Thames

Telephone: 01235 559129

Mobile: 07940451268

Roofing & PropertyMaintenance

22 Crosslands DriveAbingdon

Oxfordshire OX14 4JS


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your wall provides adequatesound resistance.

First Floor: two storeyextensions will require afirst floor, these aregenerally made up from

timber floor joists whichspan between load bearingwalls, they support floorboarding above andplasterboard is then fixed tothe underside of the joiststo provide a ceiling finishand fire resistance. The sizeof the floor joists willdepend on the span so

please contact us for adviceon the joist size required.The floor will also need toinclude sound insulationand in domestic extensions,100mm of sound deadeningmineral wool placedbetween the joists isgenerally sufficient.

The Roof Structure: the roofof your extension will needto be designed to keep outthe rain and snow and mayneed to cope with somelight loft storage loading.Generally two types of roofare used for domesticextensions:-

Flat Roofs: this is the

simplest type of roofstructure and for someextensions, generally singlestorey, a flat roof canprovide a practical andeconomic solution.Timber joists are used tospan between theloadbearing walls andbeams and these are

covered with a plywooddecking laid on firring stripsto provide a fall. Thermalinsulation is then placed

over the roof and it isgenerally finished with awaterproof covering of threelayers of bonded roofingfelt. Critical things toconsider in this type of roof

are the size and support ofthe roof joists and the waythat the roof will beinsulated and, if necessary,ventilated.

Pitched Roofs: if a flat roof isnot suitable for your needsyou are likely to require apitched roof. These aregenerally more substantialstructures that are finishedwith roof tiles or slates.The supporting structure ofthe roof can be formed intwo ways:

1. Trussed Rafter Roofs:these are quick toconstruct,measurements are taken

from site and roof

trusses are made up in afactory, they are thendelivered to site readyfor installation. Eachroof is individuallydesigned by the roof

truss manufacturerusing specialistcomputer software andthe carpenters time onsite can be significantlyreduced.

2. Traditional Roofs:A carpenter cuts atraditional roof on site.The roof structure willgenerally be designedby an Architect orStructural Engineer andthe timber is thendelivered to site wherethe carpenter will setout the roof and cuteach of the individualtimbers to size before

installing them.



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Acorn

CarpentryLimited

Carpenters &J oiners

Harwell Innovation CentreBuilding 173, Curle AvenueHarwell International Business CentreDidcot, Oxon OX11 0QG

Telephone: 01235 838570Fax: 01235 838571Email: [email protected]

Building & RenovationServices

Evergreens, All Saints Lane,

Sutton Courtenay,

Abingdon, Oxon OX14 4AG

Tel: 01235 847577

M ob: 07774 114309

All building work undertaken Extensions

Renovations

New Build

Trained Carpenters

Established over 30 years

Dom J arman

Architect

Designs and drawings prepared for

alterations, extensions andnew building work.

Planning, listed building,

conservation area and building

regulations applications submitted.

Friendly, reliable, professional

service.

Woodbury, High Street,

Long Wittenham,

Oxon OX14 4QH

[email protected]. 01865 407416

M&A ELECTRICALS30 Market Place,Wantage,Oxfordshire OX12 8AJFax-01235 762304

Tel-01235 762468

[email protected]

www.electricianoxford.co.uk

Electrical ContractorsRegistered ECA Electricians since 1985.

Your local Electrician since 1963.All Types of Work Undertaken.Portable Appliance Testing.

Electrical Goods & AccessoriesAn extensive range of goods and appliances stocked.Extension Leads, Torches, Batteries, Sockets andSwitches etc.

Lighting ShowroomWe have accounts with most lighting companies andhave access to all types of lighting.The showroom is now spread over two floors.

Lamps [Light bulbs]A large selection always in stock-if we cannotsource your lamp its not available!


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This type of roof offersthe greatest flexibility inroof shape and is oftenthe only way of roofingcomplicated extensionsespecially where the

new roof must join ontoan existing structure.

The size of the timbers andsupporting beams requiredin a roof will depend on theloadings and spans involvedin each case, complex roofswill require a StructuralEngineers design but our

Building Control Surveyorswill be happy to assist yourbuilder in designing simpleroof structures.

Once the support is in placethe roof must be covered toprovide weather protection,pitched roofs are generallyfinished with tiles or slateswith a layer of roofing

membrane or felt underthem. The tiles aresupported by the rafters viaa series of timber battens.To provide adequateweather resistance the

tiles overlap each otherand they must have anadequate pitch.For extensions it is commonto use tiles or slates thatmatch the main housealthough this is not alwayspossible if the extensionroof has a very low pitch.Our Building Control

Surveyors will be happy toassist you with anyenquiries that you haveabout roof finishes.

Stairs: if your extension hasmore than one storey youmay need to install astaircase and careful designof this can be critical to thesuccess of the extension.

If a stair is installed it shouldbe designed in accordancewith the following guidance.

Width: there is no minimumwidth for stairs in theBuilding Regulations

however they will need tobe useable. Generally stairsare 8501000mm wide.

Pitch: the maximum pitchfor the stair should notexceed 42 degrees.

Rise and Going: themaximum rise of each treadof a domestic stair should

not exceed 220mm and thegoing should be at least220mm.

Headroom: the clearheadroom over thestair should be atleast 2m.

Handrails and Balustrades:the stair should be providedwith a handrail at least

900mm high and anyexposed edges of stairs orlandings should be providedwith balustrading at least900mm high.

Fire Precautions: it isimportant that you considerfire precautions when youare designing your

extension. The mostdangerous fires generallyoccur at night wheneveryone is asleep and togive you awareness of a firethe Building Regulationssuggest that mainsoperated smoke detectorsshould be installed on eachfloor of the house when it

is extended.To prevent people beingtrapped by a fire all roomsthat do not open directly



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W. A. HINE& SON LT DBUILDERS & CONTRACTORS

Est 1955

33 Wallingford RoadGoring, Reading

Berkshire RG8 0HLTel: 01491 872433


B&BBUILDERS

6 All Saints Court

Didcot

OXON

OX11 7NG

Tel:

0 1 2 3 5 2 0 0 6 3 1

[email protected]

At New Looks we have severalservices available. Our aim is tobring you the most cutting edgein design. New products fromQUOOKER, FRANKIE,THERMASKIRT and CROWN

show our commitment to this.

Products:

Kitchens UPVC Windows & Doors Granite/Composite and Laminate worktops Built in appliances Heated skirting Boiling water taps

Services:

Kitchen installation Kitchen design and project management Full range of building services available UPVC Window & Door installation On site granite worktop measure and templates

133 Brasen ose Road, Didcot OX11 7BP

Tel: 01235 511155 Emai l : info@new look s.org.ukWeb: w w w.new looks.org.uk

New Looks Kitchens

Gary B yrneGB

P a i n t e r s& D e c o r a t o r s2 4 Ye a r s E x p e r i e n c e

Domestic & Commercial

Competitive Prices

No Job Too Small

All Out of Hours Work Carri ed Out

Mobi le : 07 75 9 34 15 25Tel /Fax: 012 35 84 72 78

gary.byrne@ hotmail.co.uk

24 Bradstocks Way, Sutton Courtenay,Abingdon OX14 4BY


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onto a hall and all first floorrooms should have awindow or door that is largeenough for people to escapethrough. If you are using awindow as your secondary

fire escape it should have aclear opening of at least0.33m2 at least 450mm widewith a cill height of between800 and 1100mm abovefloor level.

Fire is a very dangerousthing and careful designand planning are required to

ensure that the risks itposes are minimised.

Ventilation: fresh air isessential to healthy livingand the BuildingRegulations require yourextension to have adequateventilation, generally anopening window with atrickle vent is all that is

required, the windowshould have an openablearea equivalent to at least1/20th of the floor area ofthe room that it isventilating. The trickle ventis a small slot type vent thatyou can leave open to allowsome backgroundventilation without the needto open the window,generally these are found inthe top of the windowframe. If your extensioncontains a kitchen, utilityroom or bathroom you willneed to provide an extractfan in these areas and yourBuilding Control Surveyor

will be pleased to provideyou with more detailedadvice when they callon site.

Drainage: it is usuallypossible to connectdrainage from extensionsinto the existing drainagesystems. Drainage can bedivided into two types, foul

water and rainwater andgenerally speaking thedrainage systems should bekept separate. Foul drainageis generally dischargedthrough a series of pipesand manholes to a publicsewer although someproperties will have septictanks or private sewage

treatment plants. Whenplanning your extensionlook for manholes and tryand find out where yourdrains are running so thatyou can work out how anynew drains will connect tothem. It is important that allnew underground drainpipes have a diameter of at

least 100mm so that they donot block or freeze, arewatertight and havemanholes or access pointsso that any blockages canbe cleared. Where possiblerainwater drainage shouldnot be discharged to foulsewers as this can causeproblems with flooding, the

preferred solutions are todischarge rainwater tosoakaways located in yourgarden at least 5m from anybuilding or to storm watersewers if they are available.

Heating: most extensionswill need to be heated andyou will need to check with

your heating engineer thatyour existing system hassufficient capacity to heatyour extended house.

You may also need tomove your boiler, if forexample, your extensionwill cover the flue outlet.Any alterations to yourheating system should be

carried out by a suitablyqualified plumber orheating engineer registeredwith Gas Safe for gas firedboilers or OFTEC for oil firedboilers. Any new boilers willneed to be highly efficientcondensing boilers and thenew radiators that youinstall in your extension

should be fitted withthermostatic radiatorvalves so that you canensure that they useheat efficiently.

Thermal Insulation:CO2 emissions are a majorconcern in todaysenvironment and you willneed to provide a high levelof insulation within yourextension. Your extensionshould provide an insulatedenvelope so that the amountof heat escaping isminimised. The roof, wallsand floors of your extensionshould all include thermalinsulation; walls generally

have insulation placed withinthe cavity, roofs generallyhave insulation in the loftarea and sheets of insulationcan be placed beneath theconcrete of your ground floor.

Another major area whereheat is lost from buildings isthe windows and theserequire special attention:

24mm double glazing unitsincorporating low emissivityglass are generally requiredand, unless energy


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improvements are carriedout in the existing house,the window area of yourextension is limited by theBuilding Regulations to 25%of the floor area plus thearea of any existing

openings covered by theextension.

High levels of insulation canresult in problems withcondensation and care mustbe taken to ensureadequate ventilation isavailable to rooms andparticularly in roof voids.

As well as insulating yourextension you will need toconsider the efficiency ofany services you put into it.

Low energy light fittingsshould be used wherepossible and any newheating systems shouldwork to high levels ofefficiency and have suitablethermostats and controls.

Sound Insulation: to reduceunwanted noise the wallsand floor around bedroomswill need to be insulated toreduce sound transmission,this is generally achieved byplacing 100mm of sounddeadening quilt in the floorvoid and in the partitionsaround the bedrooms.

Electrical Installations: aspart of the BuildingRegulations process you will

need to supply BritishStandard Test Certificatesfor most new electricalinstallations, whenselecting your electricalcontractor please ensure

that they are competent toprovide you with these testcertificates as otherwiseyou are likely to incuradditional costs for testingthe circuits.

Glazing: to reduce the riskof people injuringthemselves, glazing in and

around doors and all glazingwithin 800mm of floor levelshould be either toughenedor laminated glass.

Conclusion: whereas a welldesigned and constructedextension is a definite assetto your home that canprovide useful extra space

and add value to yourproperty, a poorly thought-out extension can reduceyour propertys value and insome cases compromiseyour safety and thestructural integrity of yourhome. It is important toensure that you plan your

extension carefully and getthe work carried out by anexperienced contractor.

The Building Regulationsexist to ensure thatbuildings are constructed toa reasonable standard;Building Control will bepleased to provide you with

any further assistance thatyou require during thedesign and construction ofyour extension.



26/52


Tel: 01491 613066


Web: www.dparchitects.co.uk

FMB Member

General Building Works

Extensions

Refurbishments

Loft Conversions

Commercial And Domestic

Garden Walls

Repairs

New Builds

Are you considering extending your house?Then Tamdrew Builders Ltd has a selectteam of builders available to assist you withanything you require. Highly trained buildersare available to answer all your houseextensions questi ons.

Unit 3, 21 Singers LaneHenley on Thames

Oxfordshire RG9 1HBT: 01491 576761F: 01491 575277E: tamdrewbuilders@ btconnect.com

With over 21 years experience SL White Carpentryand Joinery Ltd offer high quality craftsmenservices to the Oxfordshire and surrounding area.

Our Services include:

I ExtensionsI General BuildingI KitchensI BathroomsI ConservatoriesI Bespoke JoineryI Loft ConversionsI Decking and LandscapingI Fencing and Gates (Iron/Timber)I Property DevelopmentI Restoration and Renovation work

We also offer a design assistance service free of charge.

For more information or a free no

obligation quote please call Simon on:01235 764116 / 07737 203762www.slwhite.co.uk

Mark BurkeProperty Maintenance

28 Wick Green, Grove, Wantage OX12 0AS

Telephone: 07515658391

01235201129email: [email protected]

Windows, Doors and

Conservatories

Quality and HonestyQuality and Honesty


27/52

Loft Conversions

Introduction: most houseshave a large space undertheir roofs normallyknown as the loft or attic,this space is often underutilised and in someinstances can offer an ideal

opportunity for expandingyour home. This guide hasbeen written to provide youwith useful informationabout how the BuildingRegulations will affectyour loft conversionproject.

Suitability: not all lofts aresuitable for conversionand as a first step it is wiseto go into your loft and carryout a brief survey beforeyou get too far into theplanning of your project.When carrying out yoursurvey check:

That there is enoughheight within your loft tostand comfortably,bearing in mind thatyour new floor is likelyto be around 200mmhigher than your

existing ceiling joists. That the loft space is

large enough to providea useable room.

That there arent anychimneys or servicespassing through the loftspace that will needmoving.

That your roof has feltunder the tiles or is fullyweathertight.

If the answer to all of thesequestions is Yes then yourloft may well be suitable forconversion.



28/52


Graham

Smith

Associates

1 Rose Tree Cottages

Stoke Ro w, H enley-on-Tha mes

Oxford shire RG9 5PN

Tel: 01491 681721

gr aham .smith@ rosetree.freeserve.co.uk

Structural Eng ineersStructura l Engineers

Planning Assistance

For Personal & Professional

Assistance in

Land & Planning Matters

Contact

As s o c i a t e sLand, Devel opment & Property Consultants

01235 832867

www.stewartlilly.co.uk

Stewart Lil l y

Building cont ractor of fering:

New Builds

Extension s & Alt eration s

Carpent ry & Join eryPlum bing & Heating

Electrical Work

Painting & Decorating

Tot al Pro ject M anag em ent Service

Tel: 01865 823301

Mobile: 07970 62 42 52Email: [email protected]


29/52


How to Proceed: loftconversions are complexprojects and unless you areexperienced in construction

you will need to get someprofessional advice. Theintroduction containedadvice about obtaining thisand with this in place wecan now consider some ofthe technical issues thataffect loft conversions.

Technical Issues

The Roof Structure: the roofof your home is currentlydesigned to keep out therain and snow and to copewith some light loft storageloading. After a loftconversion your roof willhave to cope withsignificantly different

loadings, a new floorstructure will be requiredand it is likely that a numberof the structural elements

will need to be altered toallow for circulation withinthe room, roof windows etc.Roofs can generally bedivided into two types.

Trussed Rafter Roofs: thesehave been common sincethe 1970s, and roofs of thistype are difficult to convert.Roof trusses are complexpieces of engineering andthey should not be alteredwithout the advice of a

structural engineer. Whenconverting this type of roofit is common for a series ofbeams to be installed toprovide support to the newfloor and to strengthen therafters, this allows thebracing sections of thetrusses to be cut out tocreate a clear floor area.

Traditional Roofs: these aregenerally made up from aseries of rafters and purlins

spanning between loadbearing walls. These roofsare less complicated toconvert than Trussed RafterRoofs, however, beams areoften required to providesupport to the new floorstructure and the existingpurlins and a StructuralEngineers design will berequired for all but thesimplest conversions.

When considering a loft

conversion dont betempted to simply boardover your existing ceilingjoists and rafters, this canadversely affect the value ofyour property and in somecircumstances can causeoverloading and endangerthe structural stability ofyour home.

Accessing your LoftConversion: if you want toconvert your loft for


30/52


Sonya

GoodwinPlastering

No job too small

01491 65149207899 756434

[email protected]

CLIVE COLLETT(Electrical) Ltd

Thistled ow n - The S q ua re

Brightwell-Cum-Sotwell

Wa lling ford - Oxon OX10 0S B

Tel/Fa x: 01491 835988

Installation Maintenance

I nspection

All types of Electrical Installation

P eriod ic Inspe ction Repo rts

Domestic

Commercial

Industrial

Free quotationsNo call out fee

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Manor Farm,

West Hagbourne

Didcot OX11 0ND

Contact Matt

07816399315

01235 [email protected]


31/52


habitable use you will needto install a staircase andcareful design of this can becritical to the success ofyour conversion.If there is enough headroom

it is often best to continuethe stair in the existingstairwell as this saves spaceand gives a feeling ofcontinuity within the home,alternatively part of a roomwill have to be partitionedoff to accommodate the newstaircase. Wherever the stairis installed it should be

designed in accordance withthe following guidance.


Rise and Going: themaximum rise of each treadof a domestic stair shouldnot exceed 220mm and the

going should be at least220mm.

Headroom: the clearheadroom over the stairshould be at least 2m, forsome loft conversions theBuilding Regulations allow areduced headroom of 1.9mover the centre of the stair

and 1.8m on the outsideedge.

Handrails and Balustrades:the stair should be providedwith a handrail at least900mm high and anyexposed edges of stairs orlandings should be providedwith balustrading at least900mm high.

For loft conversions wherespace is very limited andonly one room is created,

a specialist alternatingtread staircase can be used,these are steeper thanstandard stairs and canprovide valuable space insome circumstances.

Fire Precautions: housefires can kill and fireprecautions are a major

concern for the BuildingRegulations. The mostdangerous fires generallyoccur at night wheneveryone is asleep and togive you awareness of a fireit is important that youinstall smoke detection.When converting your loftyou will need to ensure thatyou have mains powered,interlinked smoke detectorsin the hall/landing areas onevery floor of your house.

Two Storey Houses: theBuilding Regulationsrequirements for fireprecautions in two storeyhousing are quite simple as

it is generally felt that if youcouldnt get out down thestairs you could jump or berescued from a first floor

window. If you areconverting the loft of abungalow you will need toensure that you have mainspowered interlinked smokedetection at ground and firstfloor level and that allhabitable rooms at firstfloor level have an escape

window.Escape Windows: as theirname suggests, arewindows that are largeenough to allow people toescape or be rescuedthrough them. They needto have a clear opening areaof at least 0.33m2 and a

clear width of at least450mm. The bottom of theopening light should be nomore than 1100mm abovefloor level and they shouldallow people to escape to aplace free from danger.Escape windows need to befitted with escape hingesthat allow the window to

fully open. Some of thestandard hinges fitted toUpvc windows do notachieve this so it is wise to


32/52


Buil ding ServicesStephen Tobin Mob: 07717 375190

We provide complete Building Services to include:

New-buildsExtensions Conversions

Renovation & repair workKitchens BathroomsPlumbing CarpentryElectrical Plastering

Windows & Doors Tiling

We can p roject manage all of your works

requirements

Call or emailStephen Tobin Mob: 07717 375190

[email protected]

Take a look at some previous works:

www.rsbuildingservices.com

Wantage, Oxfordshire

Hopes Design Services Ext ens io ns

New Build

Renova t ions

Condit ion s urveysfor domest ic &

public pr ojec t s

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inc luding dis a bled

fac ilit y gra nt s

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Qualified Architectural Technician

Cont a c t : G r a ha m Ho pes

Telephone/Fa x: 0 1 8 6 5 7 3 5 4 6 6

Email: ma il@ hopes des igns ervices .co . uk

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Creative BrickworkBUILDING CONTRACTORS

All Building Work Undertaken

Extensions . Patios

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17 Grunsell Close, Headington

Oxford OX3 9QQ

Telephone: 01865 751035

Mobile: 07734 706714www.creativebrickwork.net

CONSTRUCTION LTD

Master CraftsmanBuilders of Distinction

Tel: 01491 629110

Fax: 01491 628947

Grange Farm, BadgemoreHenley-on-Thames

Oxon RG9 4NZ


33/52


check this with your glazingsupplier when you orderyour windows.

Three Storey Houses: whenyou convert the loft of ahouse and create a thirdfloor the BuildingRegulations require you tolook at the fire precautionswithin the house a lot moreseriously. Mains operatedsmoke detection needs tobe fitted to give youawareness of a fire and as,due to the height of yournew floor, you can no longerrely on escaping throughthe windows the only safe

way out of the house isdown the stairs. It istherefore vital that the stairis protected from fire. Toprotect the stair all of thedoors that open onto thestair need to be half hourfire doors and the stairshould end up in a hall witha door direct to the outside.

Generally, unless a sprinklersystem or alternativeescape stair is provided,stairs cannot discharge into

other rooms in three storeyproperties.

Four Storey Houses: if yourhouse already has threestoreys, loft conversionsbecome more complicated.

You are likely to need toinstall a sprinkler system ora second escape stair andthe project will needspecialist design. Pleasecontact us and we will behappy to provide you withmore detailed advice if youare considering one of theseprojects.

Fire is very dangerous andcareful design and planning

is required to ensure thatthe risks it poses areminimised.

Bathrooms: it is often a niceidea to include a bath orshower room in your loftconversion, the best placefor this is generally directlyabove your existing

bathroom as this shouldensure that you can connectinto the existing drainageand water supplies without

the need for excessivepipework. Any bath orshower rooms will also needto be fitted with an extractfan to improve ventilation.It is a good idea to decide

on the location of anybathrooms at an earlystage in your spaceplanning process.

Thermal Insulation: CO2emissions are a majorconcern in todaysenvironment and you willneed to provide a high level

of insulation to your roof aspart of your loft conversion.The most common way ofachieving this is to place ahigh performance insulationboard in between and belowthe rafters. Unless your roofhas a breathable felt youwill need to leave a voidabove the insulation and

ensure that you haveeffective roof ventilation toprevent the build upof condensation.

Sound Insulation: to reduceunwanted noise the wallsand floor around bedroomswill need to be insulated toreduce sound transmission,

this is generally achieved byplacing 100mm of sounddeadening quilt in the floorvoid and in the partitionsaround the bedrooms. If youare converting the loft of asemi-detached or terracedproperty you will need toensure that the sound

resistance of the Party Wallis upgraded so that soundtransmission to yourneighbours is reduced.


34/52


MYERSPLASTERING

For a Free Quotation contact

Dave on 0 7771537 36 4

[email protected]

4 1HAMBLE ROAD, DIDCOT, OXON

Domestic & CommercialComplete Inter ior & Ext er ior

Renovations

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Metal Stud Work Plasterboarding Coving

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Tel /Fax : 01 23 5 81 94 04

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www.n jscons t ruc t ion .co .ukDidcot, Oxford

CARPENTRY AND BUILDI NGCONTRACTS

WHATEVER YOUR PROJECT,WE HAVE THE CONTACTS AND ADVICE YOU NEED

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CONTRACTOR SEARCH

www.homeandbuild.co.ukFor more information 0845 652 4124


35/52


Heating: to maximise theusability of the room youwill probably want to installheating, in most instancesthe most effective way ofdoing this is to extend the

existing central heatingsystem. You will need tocheck with your plumber orheating engineer to ensurethat your existing boiler hassufficient capacity to serveany additional radiators andany new radiators should befitted with thermostaticvalves to control the room

temperature.If it is not possible to extendthe existing system or if youprefer an alternativemethod of heating, e.g.electric panel heaters,careful consideration shouldbe given as to how thesecan be switched andcontrolled to ensure that

they function efficiently.

Electrics: you are likely torequire some electricalalterations as part of yourconversion. Depending onthe age and condition ofyour existing electricalsystem it is sometimespossible to extend existing

circuits but sometimes newcircuits and even a newdistribution board will berequired. It is a good idea toget advice from a competentelectrician at an early stage.

When appointing anelectrician please ensurethat they are able to issueyou with BS7671 testcertificates when they havecompleted their installationas these will be requiredbefore your BuildingRegulations CompletionCertificate can be issued

and you will incur additionalcosts if the test certificateshave not been provided.

Windows and Ventilation:any new habitable roomswill need to be ventilated.Generally this is achieved byproviding an openingwindow or roof light

equivalent to 1/20th of thefloor area of the room with atrickle vent at high level. Allnew windows must be fittedwith highly efficient doubleglazed units.

In bath or shower rooms anextract fan should be fittedand in rooms without

opening windows extractfans should be fitted thatare triggered by the lightswitch with overrun timersthat allow the fan toremain on after the light is

turned out.

Conclusion: a wellconverted loft is a definiteasset to your home, it canprovide useful extra spaceand add value to yourproperty. However a poorlyconverted loft can reduceyour propertys value and in

some cases compromiseyour safety and thestructural integrity of yourhome. It is important toensure that you plan yourconversion carefully and getthe work carried out by anexperienced contractor.

The Building Regulations

exist to ensure thatbuildings are constructed toa reasonable standard; Valeof White Horse BuildingControl will be pleased toprovide you with any furtherassistance that you requireduring the design andconstruction of your project.


36/52

Introduction: if you needmore space and you do notwant to move house youmay wish to considerconverting your garage.

Your home is probably yourmost valuable asset so it is

important that yourconversion project iscarefully planned. Thisguide is not a substitute forprofessional advice but hasbeen written to provide youwith useful informationabout how the BuildingRegulations will affectyour conversion.

Suitability: if you have abrick or block garageattached to your house it isprobably suitable forconverting. When you arethinking about whetheryour garage is suitable forconversion you might liketo consider:

Whether there are anyknown problems withyour garage, are thereany cracks in it? Is itdamp? Does the roofleak? Has the floorbeen contaminatedwith fuel or oil?

How will you get intothe new room? Have

you got or can you puta doorway through tothe garage from thehouse?

Will you have enoughparking and storagearea if you convert yourgarage?

Is there enough roomin your garage toprovide the

accommodation thatyou require or wouldyou be betterextending theproperty?

Is your existing garagebuilt from an unusualconstruction? Forexample, prefabricated

panels, concrete frameetc.

If you can resolve all ofthese issues then yourgarage may well besuitable for conversion.

How to Proceed: garageconversions can becomplex projects and

unless you are experiencedin construction you willneed to get someprofessional advice. Theintroduction containedadvice about obtaining thisand with this in place wecan now consider some ofthe technical issues thataffect garage conversions.

Technical Issues

Infilling the Garage DoorOpening: this tends to be

Garage

Conversions



37/52


Before After

the most visible part of your

conversion from the outsideand whatever you choose to

infill the opening it will need

some support. Some

garages have a foundation

that runs across the garage

opening which you can use

to support your infill.

Unfortunately the only real

way to tell if the front ofyour garage has an existing

foundation is to dig a hole

and find out.

If there is no foundation

under your garage door

opening there are two main

options. You can either:

1. Dig a foundation 1m deep

or to the same depth as thefoundations of the existing

garage, call us to inspect

the foundation and then fill

it with concrete.

Or

2. If the opening is only the

width of a single garage

door install two 150mmdeep concrete lintels across

the opening supported by

the existing foundations.

Your Building Control

Surveyor will be happy toprovide you with moreadvice about which is thebest option for you when weget to site.

With the foundations inplace the garage dooropening can now be filledin. There are several options

for how this can be done.The opening can be filled inwith brickwork to match thehouse and a window. Peoplegenerally narrow the garagedoor opening slightly as afull width window canappear out of proportion.To keep the damp out and toprovide insulation it is best

to use a cavity wall and yournew window should bedouble-glazed. Otheroptions include installing alightweight timber framedpanel with a weatherproofexternal surface andinsulation, this can bequicker and cheaper andhas the advantage that it is

easier to remove if you, orany future owners of thehouse, ever wanted toreinstate your garage.

Whichever option you

choose it is important thatthe infill panel providesadequate weatherresistance and insulationand that all of the new workis tied into the existingconstruction. Your BuildingControl Surveyor will behappy to provide you withadvice about this.

Raising the Floor Level:garage floors are generallylower than the floor in themain house and they oftenslope towards the garagedoor. For these reasonsgarage floors are generallyraised as part of aconversion. There are two

main ways of raising agarage floor. Whichever wayyou choose it is importantto consider insulation anddamp proofing.

Option 1: Concrete: usingthis method a polythenemembrane is placed overthe garage floor, floor

insulation is laid down,a second polythenemembrane is installed andthe floor level is brought up


38/52


to the same level as thehouse using concrete orsand and cement screed.

Option 2: Timber: thismethod involves placingtreated timber floor joistsonto a damp proofmembrane placed over theexisting concrete floor,placing floor insulationbetween the joists andcovering the floor joists withfloor boards or tongued andgrooved chipboard.

The floor can then be

finished with carpet,laminate or any otherdecorative surface.

Lining the External Walls:the walls used to constructgarages are not normally upto habitable standards, theyare sometimes formed froma single thickness of

brickwork and even whenbuilt from cavity masonrythey are often uninsulated.When converting yourgarage the walls will needto be upgraded.

There are three main areasof concern when upgradingwalls in a garageconversion: weather and

damp resistance, insulationand sound resistance. Theupgrading scheme that youchoose will be influenced bythe original construction ofyour garage walls, these canbe broadly divided into twocategories.

Cavity Walls: if your garage

is built from cavity walling,weather resistance anddamp proofing areunlikely to be a problem.

These walls generally havedamp proof courses andproviding that your wall is ingood condition and is notshowing signs of wateringress or rising damp, the

wall will simply requireinsulating and a plasterfinish ready for yourdecoration. There are twooptions for insulating thewall: either the cavity canbe injected with cavitywall insulation or aninsulated lining board canbe fixed to the inner face of

the wall prior to plasterboarding or plastering.Various boards are availableand your Building ControlSurveyor will be happy toprovide advice as to whichboards are suitable foryour project.

Solid Brick Walls: ingarages these are generallyonly a single brickapproximately 100mm thickand they often haveintermediate piers that

buttress the walls and givethem additional strength.A single brick wall will notprovide adequate weatherresistance to a habitableroom and a supplementarywall will need to beprovided behind the originalwall. This can be doneeither by building an

additional skin of masonryto form a cavity wall, thecavity can be insulated asthe wall is built, and thewall can then be dry lined orplastered. Alternatively anindependent timber framedwall can be constructed with


39/52


a cavity between the new

framing and the existingwall. The frame should beconstructed from treatedtimber and insulationshould be provided betweenthe timber studs. Once theframe is in place aninsulated plasterboardfinish can be applied readyfor decoration.

Occasionally garages arebuilt with 225mm thick solidbrick walls. If they are ingood condition and have adamp proof course they willnormally provide adequateweather resistance but theywill need to be lined with aninsulating board to improvetheir insulation.

Party Walls: if any of thewalls of your garage areshared with a neighbour it is

considered to be a Party

Wall. These walls will needto be upgraded to reducesound transfer betweenyour new room and yourneighbours property. YourBuilding Control Surveyorwill be happy to provide youwith advice as to how youcan upgrade anyParty Walls.

The Ceiling: unless yourexisting garage has anadequate ceiling you willneed to provide one as partof your conversion.Plasterboard is the mostcommon material used forceilings as it offers good fireresistance and flame spread

properties. Other materialscan be used but they willgenerally need to be treatedto improve their fire

performance. If the garage

is open to a roof you willneed to provide insulationabove the ceiling and theroof void will generally needto be ventilated above theinsulation to reduce the riskof problems withcondensation. In a pitchedroof fibreglass insulationwill normally suffice but

with flat roofs, where spaceis confined, highperformance insulationboards are often required.

Your Building ControlSurveyor will be happy todiscuss this with you.

Heating: to maximise theusability of the room you

will probably want to installheating; in most instancesthe most effective way ofdoing this is to extend the

Certain ground conditions will affect the ground floor detail


40/52


existing central heatingsystem. You will need tocheck with your plumber orheating engineer to ensurethat your existing boiler hassufficient capacity to serve

any additional radiators andany new radiators should befitted with thermostaticvalves to control the roomtemperature. If it is notpossible to extend theexisting system, or, if youprefer an alternativemethod of heating, e.g.electric panel heaters,

careful consideration shouldbe given as to how thesecan be switched andcontrolled to ensure thatthey function efficiently.

Drainage: if you are lookingto include a sink, bathroom,shower room or cloakroomin your conversion it is

important that you considerdrainage at an early stage.Any new appliances willneed to connect to yourexisting foul drainagesystem as they are notallowed to be connectedinto rainwater drains. Whenplanning your layouts makesure that there are suitable

routes for pipes to run to apoint where they canconnect to existing drains.

Windows and Ventilation:any new habitable roomswill need to be ventilated.Generally this is achieved byproviding an openingwindow equivalent to

1/20th of the floor area ofthe room with a trickle ventat high level. All newwindows must be fitted with

highly efficient doubleglazed units and it is wise tomake sure that they containan opener with a clear areaof at least 0.33m

2

and450mm wide which should

be large enough for you toescape through in the caseof fire. This is essential ifthe door out of your garageopens into a room otherthan your entrance hall.Special fire escape hingesshould be fitted to thiswindow to ensure that it canbe fully opened if you ever

need it. In bath or showerrooms an extract fan shouldbe fitted and in roomswithout opening windowsextract fans should be fittedthat are triggered by thelight switch with overruntimers that allow the fan toremain on after the light isturned out.

Fire Precautions: when youare investing money in yourhome it is a goodopportunity to review thefire precautions that areavailable in the existinghouse. Mains operatedsmoke detectionsignificantly improves fire

safety in the home and theBuilding Regulationsrequire that it should beinstalled where garages areconverted to habitablerooms.

Electrics: you are likely torequire some electricalalterations as part of your

conversion. Depending onthe age and condition ofyour existing electricalsystem it is sometimes

possible to extend existingcircuits but sometimes newcircuits and even a newdistribution board will berequired. It is a good idea toget advice from a competent

electrician at an early stage.When appointing anelectrician please ensurethat they are able to issueyou with BS7671 testcertificates when they havecompleted their installationas these will be requiredbefore your Building

Regulations CompletionCertificate can be issuedand you will incur additionalcosts if the test certificateshave not been provided.

Conclusion: a well designedand constructed garageconversion can be a definiteasset to your home that canprovide useful extra spaceand add value to yourproperty. A poorly thought-out conversion can reduceyour propertys value and insome cases compromiseyour safety and thestructural integrity of yourhome. It is important toensure that you plan your

conversion carefully and getthe work carried out by anexperienced contractor.

The Building Regulationsexist to ensure thatbuildings are constructed toa reasonable standard; Valeof White Horse BuildingControl will be pleased to

provide you with any furtherassistance that you requireduring the design andconstruction of your project.


41/52

Introduction: if you are

fortunate enough to have a

cellar beneath your house

and you need more space

you may wish to consider

converting your cellar. Your

home is probably your most

valuable asset so it isimportant that your

conversion project is

carefully planned. This

guide is not a substitute for

professional advice but has

been written to provide you

with useful information

about how the Building

Regulations will affect yourconversion.

Suitability: if you have a

cellar beneath your house it

may well be suitable for

converting. When you are

thinking about whether your

cellar is suitable for

conversion you might like toconsider:-

Is there sufficientheadroom in the cellar,bearing in mind that theceiling and the floortreatments that you will

have to install are likelyto reduce the availableheadroom?

Does the cellar everflood?

What is the access like?Is there a place for astaircase?

Will you have enough

storage area if youconvert your cellar?

Is there enough room inyour cellar to providethe accommodation thatyou require or wouldyou be better extendingthe property?

Domestic Cellar

Conversions



42/52


Is there any ventilationto your cellar or couldany be provided?

If you can resolve all ofthese issues then yourcellar may well be suitablefor conversion.

How to Proceed: Cellarconversions can be complexprojects and unless you areexperienced in constructionyou will need to get someprofessional advice.The introduction containedadvice about obtaining this

and with this in place wecan now consider some ofthe technical issues thataffect cellar conversions.

Technical Issues

Lowering the Cellar Floor:if there is not sufficientheadroom in your cellar it issometimes possible to

lower the cellar floor. This isnot however a simpleoperation and carefulconsideration needs to begiven to whether loweringthe floor will undermine thehouse or the neighbourshouse foundations andwhether the floor will endup below the water table

and make the property morevulnerable to flooding.Specialist advice shouldalways be taken beforeconsidering loweringcellar floors.

Waterproofing: as mostcellars are set within theground they tend to suffer

from problems with damp.If it is to be converted to ahabitable room your cellarwill need to be damp

proofed. A number ofsystems are available fordamp proofing cellars andmost of them use aproprietary waterproofrender system known as

tanking. This is applied sothat it forms a continuousdamp proof layer across thefloor and up the walls and isgenerally installed byspecialist companies whowill offer an insurancebacked guarantee for theinstallation. Protecting yourcellar from damp is animportant part of the cellarconversion process and wewill need to approvedetails of the system thatyou are using and theinstaller prior toinstallation.

Access: some cellarsalready have good stepped

access to them, whether theexisting stairs will providesuitable access to ahabitable room is a matterof judgment and ourBuilding Control Surveyorswill be happy to offeradvice. If there are no steps,or if the existing steps areinadequate, a new stair willneed to be installed. Carefulconsideration should begiven to the best locationfor the stair and this will beinfluenced by a number offactors including the layoutof the existing house andcellar, the headroomavailable and whether a

secondary means of escapecan be provided from thecellar area. Wherever thestair is installed it should be

designed in accordance withthe following guidance.


Rise and Going: themaximum rise of each treadof a domestic stair shouldnot exceed 220mm and thegoing should be at least220mm.

Headroom: the clearheadroom over the stairshould be at least 2m, forsome loft conversions theBuilding Regulations allow areduced headroom of 1.9mover the centre of the stairand 1.8m on the outsideedge.

Handrails and Balustrades:the stair should be providedwith a handrail at least900mm high and any

exposed edges of stairs orlandings should be providedwith balustrading at least900mm high.

Fire Precautions: your cellarwill need to be providedwith suitable escape routesin case of a fire. If yourcellar has a light well it may

be possible to upgrade thisso that as well as providingventilation to the room itcan provide a secondary fireescape. To be considered asa secondary fire escape itwould need to be fitted witha door or window with aclear area of at least 0.33m

2

and 450mm wide. Special

fire escape hinges shouldbe fitted to this window toensure that it can be fullyopened if you ever need it


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and you should be able toeasily climb up from thelight well to ground level.If you cannot provide asecondary fire escape thestaircase will need to end

up in a fire protectedhallway with a door directto outside.

When converting your cellarit is a good opportunity toreview the fire precautionsthat are available in theexisting house. Mainsoperated smoke detectionsignificantly improves firesafety in the home and theBuilding Regulationsrequire that it should beinstalled where cellars areconverted to habitablerooms.

Drainage: if you are lookingto include a sink, bathroom,shower room or even a

washing machine in yourconversion it is importantthat you consider drainage

at an early stage. Any newappliances will need toconnect to your existing fouldrainage system and thedrains are usually above thelevel of the appliances that

you wish to install. You arelikely to need to install apumped drainage systemand various packagesystems are available thatmacerate the drainage andpump it via a small diameterpipe to the existingdrainage system. Whenplanning your layouts make

sure that there are suitableroutes for pipes to run to apoint where they canconnect to existing drains.

The Ceiling: unless yourexisting cellar has anadequate ceiling you willneed to provide one as partof your conversion.

Plasterboard is the mostcommon material used forceilings as it offers good fire

resistance and flame spreadproperties. Other materialscan be used but they willgenerally need to be treatedto improve their fireperformance. If either your

cellar or the room above isto be used as a bedroomyou will need to install100mm of acoustic quiltwithin the floor voidbetween the rooms.

Heating: to maximise theusability of the room youwill probably want to install

heating, in most instancesthe most effective way ofdoing this is to extend theexisting central heatingsystem. You will need tocheck with your plumber orheating engineer to ensurethat your existing boiler andpump has sufficientcapacity to serve any

additional radiators. Anynew radiators should befitted with thermostatic


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valves to control the roomtemperature. If it is notpossible to extend theexisting system, or, if youprefer an alternativemethod of heating, e.g.

electric panel heaters,careful consideration shouldbe given as to how thesecan be switched andcontrolled to ensure thatthey function efficiently.

Ventilation: any newhabitable rooms will need tobe ventilated and this can

sometimes present aproblem for cellarconversions. Where thecellar contains a light wellthis can sometimes beadapted to include anopening window equivalentto 1/20th of the floor area ofthe room with a trickle ventat high level. In any bath or

shower rooms an extract fanshould be fitted and if theydo not have openingwindows extract fans shouldbe fitted that are triggeredby the light switch withoverrun timers that allowthe fan to remain on afterthe light is turned out.Where natural ventilation

through windows is notpractical a mechanicalventilation system will needto be installed and variouspackage systems areavailable on the market.Ventilation should beconsidered early in thedesign stage as, if

mechanical ventilation isrequired, the duct work willneed to be accommodated.

Thermal Insulation: CO2emissions are a major

concern in todaysenvironment and you willneed to provide a high levelof insulation within yourconversion. Your cellarshould provide an insulatedenvelope so that theamount of heat escaping isminimised. The walls andfloor of your cellar are

generally lined withinsulating boards and thewindows should include24mm double glazing unitsincorporating low emissivityglass. As well as insulatingyour extension you willneed to consider theefficiency of any servicesyou put into it. Low energy

light fittings should be usedwhere possible and any newheating systems shouldwork to high levels ofefficiency and have suitablethermostats and controls.

Electrics: you are likely torequire some electricalalterations as part of yourconversion. Depending on

the age and condition ofyour existing electricalsystem it is sometimespossible to extend existingcircuits but sometimes newcircuits and even a newdistribution board will berequired. It is a good idea toget advice from a competent

electrician at an early stage.When appointing anelectrician please ensurethat they are able to issueyou with BS7671 testcertificates when they have

completed their installationas these will be requiredbefore your BuildingRegulations CompletionCertificate can be issuedand you will incuradditional costs if the testcertificates have notbeen provided.

Conclusion: a wellconverted cellar can be aninteresting space and canbe a great way of gettingextra room in your house.Cellar conversions are oftennot simple projects and apoorly thought-outconversion can reduce yourpropertys value and in

some cases compromiseyour safety and thestructural integrity of yourhome. It is important toensure that you plan yourconversion carefully and getthe work carried out by anexperienced contractor.

The Building Regulations

exist to ensure thatbuildings are constructed toa reasonable standard; Valeof White Horse BuildingControl will be pleased toprovide you with any furtherassistance that you requireduring the design andconstruction of your project.


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Other

AlterationsIntroduction: a number ofhome improvement projectsare covered by the BuildingRegulations and thischapter sets out to explainhow the BuildingRegulations affect some of

the projects that you maybe considering.

This guide is not asubstitute for professionaladvice but has been written

to provide you with usefulinformation about how theBuilding Regulations willaffect your project.

Removing InternalWalls

Internal walls have anumber of functions, someare fundamental to thestructure of the house,some offer fire protection to



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the stairway and othersmerely divide up the spacewithin the house and can bealtered or removed withvery few issues.

Load bearing walls are

fundamental to thestructure of the house andcareful consideration needsto be given before they canbe altered or removed.Alteration or removal of loadbearing walls requiresBuilding Regulationsconsent and generallyspeaking a structural

engineer should becommissioned to design thealteration. The structuralengineer will considerwhat loads the wall is takingand will design a beam and,if necessary, othersupporting structure toensure that the loads thewall was carrying are safelytransmitted to the ground.We will then inspect thework as it progresses andthen issue a completioncertificate to show that thework complied with theBuilding Regulations.

The walls around yourstaircase offer you some

protection to allow you toescape if your housecatches fire and thealteration of these wallsrequires BuildingRegulations consent.If these walls are removedit is essential that yourhouse is fitted with mainsoperated smoke detection

and that all of your roomshave windows suitable forfire escape purposes(see Fire Precautions

Domestic Extensions).If you wish to removeone of these walls contactus and we will arrange tovisit you to establish

whether the walls areessential to the fireprotection within yourhouse and advise what,if any, additional work isrequired to allow thealterations to take place.

Bay Windows andChimneys

In Building Regulationsterms these are basicallysmall extensions.They require BuildingRegulations consent andmuch of the guidance in theExtensions chapter isrelevant albeit on asomewhat smaller scale.

Chimneys require liningwith a flue liner that issuitable for the fire thatthey will serve and the

installer should testthe flue prior tocommissioning the fire.

We will carry out a series ofinspections on theseprojects and issue acompletion certificate whenthe works are satisfactorilycompleted.

New Drainage

Replacement kitchens andbathrooms do not generallyneed Building Regulations

consent but where newdrainage is installed toserve a new bathroom orother appliance BuildingRegulations consent isrequired. With theseprojects we will carry out aseries of inspections toensure that the drainageand ventilation is

satisfactory and issue acompletion certificate whenthe works are satisfactorilycompleted.

In certain areas radon protection will be required


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Replacement Boilersand Alterations toElectrical Systems

These alterations require

Building Regulations

consent although in practicemost of this work is carried

out by contractors who can

self certify their work.

Details of the self

certification scheme are

given in the introduction to

this guide and, if your

contractor is able to self

certify, you will not need to

make a separate BuildingRegulations application.

If you wish to use acontractor who is notregistered with a selfcertification scheme please

contact us and we willarrange for the necessaryapplication to be submitted,carry out the relevantinspections and issue yourcompletion certificate whenwork has been satisfactorilycompleted.

Whichever scheme you use

make sure that you get the

completion certificate asyou will need this if youwish to sell your house.

Conclusion

This guide has endeavoured

to provide usefulinformation about a rangeof typical domestic projectsand we hope that you havefound it useful.If you need any furtherinformation about a projectthat you are consideringplease contact us and wewill be happy to provide

further advice.


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Radon: Radon is a naturalradioactive gas. Youcannot see, smell, hear orfeel it. It comes fromminute amounts ofuranium that occurnaturally in all rocks and

soils and the air in allbuildings contains adegree of radon.

The gas can move throughcracks and fissures in thesubsoil and eventually tothe atmosphere. Most ofthe radon will disperseharmlessly but some willpass from the ground and

collect in spaces under orwithin buildings.

Some areas of the countrymight have unacceptablyhigh concentrations unlessprecautions are taken; thegranite areas of South-West England is one ofthese areas.

The level of radonprotection required to yourextension depends on thelocation of your property.This can be determinedeither by consulting yourlocal Vale of White HorseDistrict Council BuildingControl Services office orby accessing the maps on

the Building ResearchEstablishment website.The maps indicate thehighest radon potential

within each 1-km grid anddetermines whether full orbasic radon precautionsare required or if radonprotection is not neededat all. More accurateinformation is available

from the Health ProtectionAgency or the BritishGeological Survey.

Radon protective measurescan be included relativelyeasily and cost-effectivelywithin extensions todwellings.

All extensions to dwellings

which fall within a full orbasic radon protection areawill be required toincorporate an appropriatelevel of radon protection ifa new ground floor isprovided.

Full radon protection:The damp proof membrane(minimum 1200g) acts asthe radon barrier. It isimportant that themembrane extendsthrough the cavity and islinked with a cavity tray.A subfloor sump is alsorequired. Where theexisting house has a solidfloor the sump could be

used to reduce the levelof radon in both theextension and theexisting building.

Radon



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Basic radon protection:Only the continuous dampproof membrane is required.

The detailing in both caseswill depend on the type ofconstruction used and thepositioning of the dampproof membrane, your localsurveyor will be able to giveyou further guidance,alternatively examples areprovided on the BREwebsite.

Wherever possible theconstruction joint between

the new floor and theexisting house should besealed. Where radonbarriers have beenincorporated in both thenew floor and the existingfloor, the aim should be tojoint the two barriers wherethey meet within the wall ofthe house. This is difficultto achieve in practicewithout damaging theexisting barrier and asimpler alternative is to cuta chase in the wall slightlyabove or below the existingbarrier in which to tuck thenew barrier.

If the existing house has a

beam and block orsuspended timber floor,

care should be taken to

ensure that the provision of

sub-floor ventilation is

maintained.

It is recommended that you

have your house measured

for radon before plans areprepared. Ideally

measurement should be

over at least 3 months; the

Health Protection Agency

(HPA) can provide detectors

for this purpose. If your

dwelling is found to exceed

the current recommended

action level, appropriateprotection measures can be

incorporated into yourbuilding project.

Useful contacts

HPA Radon Studies Group,Radiation ProtectionDivision, Health Protection

Agency, Chilton, Didcot,Oxon, OX11 0RQwww.ukradon.org

Building ResearchEstablishment, Garston,Watford, WD25 9XX

Documents

Guide to Extending Your Home