For advice on planning applications :

call 01296 585679

Planning

AYLESBURY VALE DISTRICT COUNCIL

The Gateway Gatehouse Road Aylesbury Bucks HP19 8FF

Tel: 01296 585679 Text Relay: Prefix telephone number with 18001devcon@aylesburyvaledc.gov.uk

www.aylesburyvaledc.gov.uk

Adopted by the Council on 16th January 1995following public consultation

© Aylesbury Vale District Council

DesignGuide

BuildingMaterials

Stone

and

Slate

Timber

and

Thatch

Brick

and

Tile

For advice on building control queries :

call 01296 585460

7 Modern Materials:There is no presumption against modern materials,wisely used; new materials have a place. There areexamples of commercial and industrial buildings in theDistrict that owe their success largely to the skilful useof modern materials, inthese instances, highquality modern materials wereemployed. New products should however be permanentand capable of ageingand weathering in anattractive way.

In special areas, wherethere is an historiccontext, modernmaterials are often lesssatisfactory unlessselected to complement,or otherwise becompatible with existing traditionalbuilding materials,particularly those which give localcharacter or identity.

8 Concrete Products:Concrete composites weather differently from naturallyderived materials such as brick, witchert, stone andtimber. The use of cement render, concrete products e.g.bricks, blocks and tiles, do not always providesatisfactory weathering performance or compatibilitywith other materials used in the locality.

Concrete based materials can be subject to colourfading, patchy or differential weathering and staining.In considering materials, the Council is aware thatbuildings may well last hundreds of years and planning officers will therefore wish to be satisfiedabout the long term implications of agreeing materialscontaining concrete.

2

Innovative commercial buildings are

associated with quality materials

1 Introduction:This guide is intended to help people applying forplanning permission understand the Council’s attitudeto building materials. Materials can be as important asdesign in determining the appearance of a new building.

The guide is not mandatory and each case will beassessed on merit. However, context can demandcompliance with main points; for example, edge ofsettlement locations, prominent sites, ConservationAreas and areas of landscape importance.

The Council has committed itself to maintain localidentity and rural association through the choice ofthose materials, which enhance established character.

The guide applies to all development work, whethernew build, alteration, extension, repair or minor changeand to all categories of development, industrial,commercial or residential.

2 Advice:Planning Officers are available to advise on suitablematerials, although there is no substitute for goodarchitectural advice. The employment of a CharteredArchitect is therefore highly recommended.

3 Statutory Listed Buildings:The advice in this guide does not necessarily apply tostatutory Listed Buildings of architectural or historicinterest. The Council’s Historic Buildings Advisor willbe pleased to give specialist advice on alteration,extension or repair with regard to Listed Buildings,including appropriate materials and their use.

4 Policy Context:The Council’s Local Plan requires an approach todevelopment, which respects the traditional character ofthe rural landscape, towns and villages. This issupported by policies in the Structure Plan andPlanning Policy Guidance issued by the Government.

5 Application of Guide:There are three circumstances where natural or“handmade” materials may be insisted upon:-

l On Listed Buildings or for buildings adjacent to Listed Buildings where it is necessary to respect special character or the setting of Listed Buildings;

l On buildings in the countryside that are within Areas of Attractive Landscape (AAL) or Outstanding Natural Beauty (AONB);

l Within Conservation Areas and on prominent sites adjacent to a Conservation area.

6 Local Character:In the past, the use of particular materials was localised,determined by availability and limited by the difficultyor the expense of transportation. Over the years, manyindividual settlements achieved an association withlocally derived materials, which now helps providedistinct identity. Indigenous materials give a sense ofplace, continuity and permanence, which can assist, in assimilating new development.

1

Local character

can be defined by

the underlying

geology

12 Witchert: (Also spelt wychett)This is found in the vicinity of Dinton, LowerWinchendon, Haddenham, Long Crendon, Chearsleyand Cuddington, as far north as Ludgershall and as fareast as Bierton. Witchert is a naturally occurringmixture of clay and chalk which, when mixed withchopped straw and as little water as necessary toachieve a malleable substance, is built up in layers (orrises) on a stone or rubble footing (grumpling).

Witchert is susceptible toerosion and needs weatherprotection by a clay pantilecoping and a lime plaster orlime wash over verticalsurfaces. Originally, witchertwalls were thatched andsome have old plain tilecopings, pantiles being a later tradition.

Lime putty mixed with sharpsand is the most suitable material for witchert repair, butthere are specialists who caneither reconstitute or preparewitchert for reconstruction ofdamaged walls.

The conservation of this unique form of construction isimportant, and the use of cement based products forwitchert repair or replacement is inappropriate.

4

Modern witchert houses,

constructed this century

Detail of

witchert wall

construction

showing “rises”

Many witchert walls

were originally thatched

Arrangement of plain clay tiles

to protect the material below

A traditional

witchert

house

9 Plastics:In a traditional context, plastic products may beinappropriate. Plastic cannot be painted, it can dull, and it is often different in colour and texture and willnot develop the same patina of age as suitable timberor tiles. Metal rain goods are better suited to historiccontexts and dark coloured plastic rain goods are oftenmore suitable than lighter colours.

10 Bricks:Bricks are the most widespread traditional buildingmaterials in Aylesbury Vale. Typically characteristic are locally derived relatively smooth faced and warmcoloured, red/orange and red/brown bricks.

Parts of the Vale are stillstrongly associated with apredominance of local brick.Examples are Brill, Hardwick,Whitchurch and Waddesdon.Brickyards in the Quainton/Westcott and Pitstone areaproduced a distinctive lightyellow (Gault Clay) brick found indomestic buildings nearby.

Stretcher bond brickworkis associated with moderncavity wall construction;however, there may beinstances when simulatedFlemish bond is requiredusing snap “headers” (halfbricks). Flemish bondbetter complements anhistoric context.

11 Mortar:The correct brickwork mortar mix is as important aschoosing a suitable brick. The recommended mortar mixfor an historic context is 1 part lime putty to 3 partssand. Lime is preferred to cement because it allows themasonry to breathe, accommodates movement and is oftraditional appearance.

For stonework, the colour and texture of sharp, gritty sandshould be appropriate to the type of walling, as stonerequires mortar which echoes its colour and texture.

Mortar mixes on stone or brick surfaces using aconcentration of cement are not aestheticallyacceptable. For normal use, a recommended mix is 1part lime and 3 parts sharp washed sand. For exposedwalls, copings and bottom courses, hydraulic limefacilitates damp resistance.

Stone and brickwork requires careful pointing for newwork on older buildings. Pointing should be flushjointed, brushed back to expose the aggregate; a slightlyrecessed joint can be used with frost resistant bricks(FL Quality). Proud (ribbon) and weather struckpointing is to be avoided, for aesthetic and practicalreasons.

3

Traditional Flemish

Bond brickwork

Simulated Flemish

Bond brickwork

15 Timber:Deep wood boards(225mm) are atraditional featurefor barns and out-buildings. Theyprovide an excellentmeans of reducingthe visual impact ofgarages and forelements of newbuildings

16 Roofs:Roof shape, pitch and materials contribute to localidentity. In Aylesbury Vale, the use of steep dualpitched roofs in clay plain tiles is predominant on olderbuildings. Slate and clay pantiles are also widespreadroof materials.

There are in the Vale a considerable number ofthatched buildings; long straw is the material mosttraditional to the area. A change from long straw tocombed wheat or water reed or changes to the ridge are not encouraged as it would lead to a loss of localdistinctiveness.

Materials used for roofs areassociated with differentroof pitches. Thatch israrely laid under a 50

o

pitch, slate is normallylaid between 20

o- 35

o, clay

plain tiles are generallylaid between 40

o- 60

oand pantiles are

usually laid at about 40o.

6

Tar coated timber cladding has a less

strident appearance than brick

Steep pitched roofs in

clay tiles complement

the Vale’s rural

character

Swept dormers are

often the least

visually intrusive

One method of

simulating a

traditional

verge

detail

13 Render:Traditionally, lime render was used as a repair orprotection to brick, stonework and witchert walls.Render composed of cement and sand, but without lime, can appear uncompromising; it is also susceptibleto cracking because of its intolerance to movement andwill trap moisture, the greatest enemy of historicbuildings.

For historic buildings a traditional lime render givesgreater flexibility and if left unpainted or just limewashed acquires a mellow effect. Smooth renderfinishes using a wood float (not steel) or a lime roughcast finish respects the character of the District.

Render should be applied in a minimum of two coats.Aggregate blocks or keyed Flettons (not insulationblocks) should be used for modern structures where therender is intended as they provide a good anchor andavoid showing through after damp weather. In thissituation, render should consist of not more than two12.5mm coats comprising a mix of one part cement, two or three parts lime and nine or twelve parts sharpsand (1.2.9 or 1.3.12).

Alternatively, one coat of maximum 15mm thickness isacceptable and the job specification should includerinsing the wall concerned for one hour beforerendering to reduce suction. The sharp sand should bewell-graded and of a mid colour.

14 Stone:Natural stoneshould be usedin favour ofreconstitutedstone, preferablyfrom matchingsources.Correctly,coursedappropriate stone has atimelessquality andwill reinforcethe character ofstone builtareas.

5

Coursed stone

with quoins and

stone mullions

to windows

Roughly

coursed

limestone

Rubble

limestone with

brick dressings

Bonnettiles tohip

buildings andchurches frequentlyused flint with brickdressing. Flintshould be laid inlime mortar. Bothknapped and cobbled forms of flintconstruction arefound in the area.

20 Surfaces:The secret of successful surface treatment is simplicity.Brick, clay paviors, stone slabs, gravel or similar natural materials are recommended for unadopted carparks, forecourts or other hard open surfaces. Peashingle and concrete setts are not suitable for largeareas unless visually broken up with planting.

Granite setts are preferred for roadway edges,particularly if incorporated into a dished drainagechannel made from setts. In Conservation Areas, setts,granite kerbs, natural stone and clay paviors arepreferred. As with brick and stone, “proud” pointing ofsetts is to be avoided.

21 Boundaries:

Materials used to construct boundary walls shouldmatch or complement those used for local boundarytreatment, for example; in an area where stone hastraditionally been used for front walls, brick and / ortimber will appear out of place.

8

Flint panels are

attractive if lime

mortar is used

It is important that new roofs of traditional form arenot spoilt by modern fitments, for example, stainlesssteel or galvanised flue outlets, prominent ventilatorson ridges, eaves or roof slopes, over-dominant rooflights or unsuitable interlocking concrete tiles. Theprovision of a substantial chimney stack can be of avisual and practical benefit and can be used toconceal central heating flues or other outlets. Mosttraditional forms of chimney pots are still inproduction.

17 Tiles:Plain clay tiles are preferred for roofs, where roofs arehipped, then bonnet hip tiles are preferred for hipridges as this gives a complete and harmoniousappearance to the roof as a whole. “Handmade”, that is, irregular clay tiles which match earlier products,may be required for Listed Buildings or ConservationAreas.

Machine made clay tiles are generally less suitable than “handmade”, but these are preferred to concretetiles. Plain tiles are always preferable to concreteinterlocking tiles by virtue of their size and lappedarrangement.

18 Slates:Natural slate is an acceptable roofing material whereclay roof tiles do not predominate. Slate is aestheticallysuperior to machine made composite or slate colouredconcrete roof tiles. Traditional lead rolls or blue ridgesare frequently used where natural slate is used inConservation Areas.

19 Flint:Flint from the Chilterns and the area west ofWendover is linked with the construction of labourers’cottages and boundary walls. 19th century farm

7

Tile hanging can aid visual

integration of houses

Local brick and flint

is encouraged in the

Chiltern area

Natural

surface

materials are

important in a

traditional

context

Bound gravel

Granite

setts for

highway

cross-over

Edging in

natural

setts

Suburban types of

boundary are often

inappropriate in a

rural area

Local stone, native species hedging, estate railings orpost and rail fences are most acceptable in rural areas.Brick, metal railings, timber paling and weatherboardare preferred rather than ranch style fences, walls ofreconstituted stone, or panel fences.

22 Windows andDoors:

Timber windows anddoors of traditionalproportions, detailingand construction arepreferred. Self-coloured or plasticframed windows anddoors will seldom beconsidered acceptablein ConservationAreas. Paintedsoftwood orindigenous hardwoodare recommendedwindow materialsalthough stainedsoftwood may be a lessexpensive alternativein some locations.

9

Modern timber

window with

overlapping

casement and

relatively thin cill

The arrangements of openings are

often local features

Traditional designs

with opening and

fixed lights of equal

dimensions

Modern timber window

arrangement of

unbalanced appearance

10

Examples of modern buildings that use

traditional materials

Plain claytiles

Claybrick

Naturalslate

Clay

pantiles

Claybrick

All roofslopes ofthe samepitch

Substantialjoinery

Deeptimberboards

Limerender

Lead

Planning Permission:In Conservation Areas building materials will usually be considered as part of an initial planningpermission and not treated as a reserved matter. This reflects the importance of materials in anhistoric context. Elsewhere, it is advisable to discussand resolve the issue of acceptable materials(including surface materials) at an early stage. Toassume that the Council will approve a particularproduct may lead to disappointment.

Traditional

timber window

with a flush

casement and

deep cill

Boundary materials should suit the

character of the area

23 Colour:Strong, but subdued shades are preferred forwoodwork on older buildings. Off white or creamtints suits all buildings better than brilliant white,this is particularly true of render finishes.

Wall areas

dominate

openings

Reference to

chimney stack