Timber Frame Erector Knowledge Skills Workbook · Timber Frame Erector Knowledge Skills Workbook 3 ... competences of existing timber frame erectors ... 18 Timber Frame Erector Knowledge

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Timber Frame Competency

Award Scheme

Timber Frame Erector

Knowledge Skills Workbook

In association with

Silver

Level

Timber Frame ErectorKnowledge Skills Silver Workbook

Name:

Position:

Company:

Date Issued:

Assessor:

Contents

3Timber Frame Erector Knowledge Skills Workbook

1 Introduction and Welcome 5 1.1 The Timber Frame Erector Training Programme 6

2 Aims and Objectives of Training 7 2.1 Aims and Objectives of Training 8

3 What is Timber Frame? 11 3.1 What is Timber Frame? 12

4 Benefits of Timber Frame 15 4.1 Benefits of Timber Frame 16

5 History of Timber Frame 21 5.1 History of Timber Frame 22

6 The Processes Involved in Timber Frame 27 6.1 The Processes Involved in Timber Frame 28

7 Drawings and Documents 31 7.1 Drawings and Documents 32

8 From Soleplate to Roof 33 8.1 From Soleplate to Roof 34

9 Fire Resistance 39 9.1 Fire Resistance 40

10 Acoustics 43 10.1 Acoustics 44

11 Differential Movement 45 11.1 Differential Movement 46

12 Building Insulation 49 12.1 Building Insulation 50

13 Vapour Control Layers 51 13.1 Vapour Control Layers 52

14 Final Review 57 14.1 Final Review 58 14.2 Learner Feedback Form 60

4 Timber Frame Erector Knowledge Skills Workbook

Section 1 Introduction and Welcome


1.1 The Timber Frame Erector Training Programme 6


Section 1 | Introduction and Welcome

1.1 The Timber Frame Erector Training Programme

Welcome to your Knowledge Skills silver workbook.

The production of these workbooks has been

supported financially by CITB. The Structural Timber

Association (STA) is extremely grateful to them.

The Structural Timber Association (STA), on behalf of

the industry, has developed this training programme

with CITB to provide recognition of the skills and

competences of existing timber frame erectors

together with raising the skill levels of any unskilled or

untrained timber frame erectors to an acceptable level

of competence.

The programme will also provide career paths for

timber frame erectors and assist young entrants to

the timber frame industry. Over time the intention is

to allow only those erectors who are qualified to erect

timber frame buildings.

A structured training programme has been devised

at three levels:

B Bronze

S Silver

G Gold

Each of the three levels is split into three modules

– Health and Safety Skills, Knowledge Skills and

Practical Skills.

For most of us, our home is our largest expense and

we expect it to be built to the highest standards by

well-trained and suitably qualified people. By using

these workbooks, we, as an industry, can now provide

you with the opportunity to achieve this goal. Also by

having a qualified workforce we can compete with the

rest in quality and workmanship.

We hope you enjoy working through this workbook.

Please add to it in any way you wish and we look

forward to awarding you with your Timber Frame

Competency Award qualifications in the near future.

Andrew Carpenter,

Chief Executive, STA.

Education and training STA/CITB

If you have any queries or require further information

on this or any other education and training matter,

either seek advice within your company, or contact

the CITB directly:

National Specialist Accredited Centre

CITB

Units 1 and 2

674 Melton Road

Thurmaston

Leicester

LE4 8BB

Tel: 0300 456 5561

Fax: 0300 456 5562

Email: [email protected]

Section 2 Aims and Objectives

of Training

2.1 Aims and Objectives of Training 8



2.1 Aims and Objectives of Training

Knowledge skills

Welcome to the Knowledge Skills silver workbook.

This Knowledge Skills silver workbook looks at

the background knowledge you need to know and

understand in order to become an essential member

of your team.

The aim is to give you the necessary knowledge so

that it will help to develop your all-round skills and

understanding by guiding you through the topics to

be an on-site erector.

What is in this workbook?

The workbook has 11 sections:

1. What is Timber Frame?

2. Benefits of Timber Frame

3. History of Timber Frame

4. The Processes Involved in Timber Frame

5. Documents and Drawings

6. From Soleplate to Roof

7. Fire Resistance

8. Acoustics

9. Differential Movement

10. Building Insulation

11. Vapour Control Layers

Each section follows a similar pattern:

you will be given information to read that explains

what you will be required to do followed by some

exercises to complete

where you see a white ‘Activity’ box (example

below), this will indicate that there is a task for you

to do. If you can’t fit your answers in the space

provided, please use a separate sheet

the activities are designed to help you find out

about different topics within the workbook

at the end of each section there are some

questions for you to answer. These are designed to

check your understanding and to identify any areas

that you may need to brush up on

the workbook has been designed to be enjoyable

as well as informative

on completion of this course you will gain suitable

recognition that employers now expect

What qualifications can

be obtained?

The workbook will help you to gain the STA/CITB

silver award, and provide evidence towards your

vocational qualification.

Activity

Section 2 | Aims and Objectives of Training


Outlining of training programme:

The silver and bronze training programmes’

Knowledge Skills are the same, as this information

is fundamental to being able to erect a satisfactory

building.

G

S

B

The training programme consists of

three levels:

Bronze Silver Gold

Each level of programme has three modules as shown below –

each of the levels follow the same structure

Health and Safety Skills

1Practical Skills

2Knowledge Skills

3

1. This workbook does not replace your own company’s documents and/or the main contractor’s site rules.

2. Furthermore it supports the small handbook titled: A Pocket Guide to Timber Frame Construction.

Please note

Aims and Objectives of Training | Section 2


Section 2 | Aims and Objectives of Training


Section 3 What is Timber Frame?

3.1 What is Timber Frame? 12



3.1 What is Timber Frame?

As its name implies, timber frame construction is

a method of building that relies on a timber frame

as the basic means of structural support.

By adding sheathing material this stiffens the structure

and the frame itself is then capable of withstanding:

lateral loads

multi-storey floors

allowing wide span requirements

Factory-manufactured timber frame guarantees the

highest level of accuracy and quality and significantly

simplifies the on-site construction.

During construction, the timber frame is covered:

internally by plasterboard and filled with high

performance insulation

by moisture and vapour barriers that are

incorporated within the building

externally with the outer leaf of the wall which can

be of any standard finish such as stone, brick,

render or timber

Roofs are also constructed in timber and are

supported on the structural timber frame at internal

load-bearing timber wall panels, and party wall

frames.

Throughout the country you can now see

the flexibility of design and layout of timber

frame construction in the variety of buildings

constructed in this way.

Housing

Timber frame’s traditional market

This method is used to construct everything from

bungalows to multi-storey flats; from high-volume

quality developer housing to individually

commissioned dream homes. Locations range from

inner cities to offshore islands, from suburban estates

to single plots.

Industrial and commercial field

Timber frame technology is now being applied to a

wide range of projects of medium-rise buildings up to

18 m high, such as:

schools

healthcare facilities

community centres

sports halls

funeral parlours

hotels

business units

churches

Section 3 | What is Timber Frame?


What is Timber Frame? | Section 3

In particular, timber frame is now proving itself

in mid-rise construction, up to five, six and even

seven storeys.

A qualified structural engineer certificates every

timber frame project.


Section 3 | What is Timber Frame?


Section 4 Benefits of Timber Frame

4.1 Benefits of Timber Frame 16



4.1 Benefits of Timber Frame

When you consider that the majority of newly built

homes are now using timber frame, it is obvious

that there are marked benefits from this type of

construction.

Countries with wet and harsh climates, like Scotland,

Scandinavia, Ireland etc. are increasingly choosing

timber frame as the preferred method of building new

homes and, in doing so, are reaping the benefits listed

in this section.

In fact over 70% of the population in the

developed world lives in timber frame housing.

This includes North America, Scandinavia, Australia

and Japan.

Did you know?

From the outside, a timber frame house looks the

same as a traditional home.

As an example the diagram shows the UK timber

frame market share percentage INCREASING year

by year.

2003200220012000199919980

2

4

6

8

10

12

14

16

18

%

Timber frame has many benefits and for these to be

achieved they must be erected with skill and care.

These are exciting times for timber frame with it

gaining such a market share.

So, the reason you are erecting a timber frame

property will be because of one of the following

reasons – if not all of them!

Summary of benefits for the builder and

developer

Speed of construction

Not weather dependent

Removes outer cladding from the critical path

Reduced drying-out time

Reduced material handling and distribution

Design flexibility

Potential for reduced build costs

Improved site productivity

Reduced waste

Better quality = fewer call-backs

Reduced programme length

Summary of benefits for the customer or

house owner

Lifestyle approach

Environmentally friendly

Dimensionally accurate

Low running costs

Comfortable home

Improved quality

You are expected to remember these benefits and

make sure they are all achieved through your work.

Section 4 | Benefits of Timber Frame


Benefits of Timber Frame | Section 4

You also need to consider the following reasons:

Traditional

Timber is the oldest construction material known to

man. Modern timber frame construction has evolved

over many centuries, and there are many such

structures still standing built over 200 years ago.

Durable

A correctly constructed timber frame building is at

least as durable as a building constructed using any

other material.

Energy efficient

The performance of standard construction is higher

than that demanded under current legislation.

New generation panels can incorporate a thermal

membrane to give even greater insulation qualities.

The high insulation means that the structures are

extremely economic to run and can provide ‘u’ value

calculations to enable heating engineers to design the

most appropriate system.

Strong

Structural engineers produce calculations to prove

that the timber frame will not only support the building

and cladding material, but will also withstand the local

wind conditions and other exposure factors. Timber

frame structures are also very resilient, and can

withstand impact far better than masonry structures.



Precise

Timber frame panels are manufactured under strict

quality control within set tolerances. This means that

right angles are true, verticals are plumb and edges

are straight.

Controllable

Sites are tidy, as materials are incorporated into the

building once they are delivered, and so do not need

to be stored. Material theft is drastically reduced.

Drying out and shrinkage cracks are reduced with

timber frame construction, resulting in much lower

maintenance costs.

Environmentally friendly

The major man-made cause of carbon dioxide

emissions in the UK is the burning of fossil fuels for

heating and power. A timber frame building containing

a high level of insulation reduces the amount of

energy required to heat it. In addition to this, the

embodied energy costs in producing the building

materials are considerably less than those in other

forms of construction.

Timber frame heat retention

Only timber from managed forests is used in the

manufacture of timber frame components.

Harvesting mature trees and replanting new ones

creates a natural cycle.

More trees are planted than are felled so an increase

in the volume of the trees is created.

Growing trees absorb carbon dioxide and, by

photosynthesis, convert it into oxygen.


Mature trees absorb less carbon dioxide, and hence

replanting them with young trees increases a forest’s

ability to absorb carbon dioxide.

The flexibility of timber frame allows design features

such as jettied floors and cantilevers that would not

normally be economic.

A timber frame building can be clad with any number

of traditional materials, both internally and externally,

which enables it to harmonise with the local

surroundings.

Other considerations you should also be

aware of are:

Planning

All planning authorities accept timber homes and

process applications for planning permission in the

same manner as for other dwellings.

Fire safety

Timber frame houses meet all the fire standards

required under the current Building Regulations.

Mortgages

Timber frame is treated in exactly the same way as

any other build method.

Benefits of Timber Frame | Section 4



Section 5 History of Timber Frame

5.1 History of Timber Frame 22



Section 5 | History of Timber Frame

5.1 History of Timber Frame

This section provides you with a short history to

timber frame buildings and their origins.

Early construction

The dates of developments of timber frame in the UK

vary depending on the locality.

However, timber frame was used during the late

medieval period that started in Britain about 1200 and

ended about the early 16th Century.

The first part of this house was built between

1600 and 1700.

These dates are later than for mainland Europe

because it took time for the changes to move north

west, although experts have differing views.

Across Britain, developments in house building started

earlier in the wealthier south east of England and

generally spread north west to the Midlands and then

further north over a period of a hundred years

or more.

Until about 1200 in areas with supplies of wood, many

dwellings were made of posts (‘earth-fast posts’)

pushed into the ground to keep them upright. Other

wooden members, also made from young trees and

branches, were added to give rigidity, and a thatched

roof was added.

However, in time the posts rotted in the ground and

the dwelling usually lasted no more than a generation.

Indeed, the earliest timber-framed houses existing

today are of this construction and are believed to have

been built in the middle of the 13th century. They are

at Boxted in Kent, and at Upton Magna just west of

Shrewsbury recently dated to 1269.

By the late 14th century timber framed peasant

houses were being built in this country, many of which

survive today along with similar examples in Germany,

France and Canada.

The oak used for the frame was cut during the winter

or spring and used immediately, partly because

seasoned oak was very hard to work with.

This partly accounts for the interestingly distorted

timbers in old houses.

These late medieval houses, occupied by merchants,

farmers, craftsmen and other prosperous people, were

Open Hall Houses (a basic design that had been in

use for centuries).

The largest part was taken up by the Open Hall, which

was used by the master, his family, servants and

farm labourers as a dining and general living area.

Indeed, it was the dominant room from the wealthiest

downwards until the layout was modified or replaced

during the transitional period, which came at the end

of the late medieval period.

These changes eventually led to the modern designs

of the Georgian and Victorian periods.

There was little separation into social classes as far

as the mechanics of living were concerned.

The Hall was open to the thatched roof, through which

escaped the smoke from a fire placed in the centre in

wealthier houses, or at the side in poorer ones.

There was no ceiling and no room above. The smoke-

blackened roof timbers are often a clue today that a

much altered timber house was once an Open Hall

House.

There are many Open Hall Houses in Britain, especially

in Kent. Many have been modified over the years.

By the end of the 14th Century many substantial

houses had been built in the south east of England

for peasants. By the end of the 16th Century humbler

dwellings were seeing the benefit of this type of

construction and layout.

The ground floor was made of beaten earth mixed with

clay and often animal blood as a hardener, whilst in the

south east, beaten chalk and soured milk were used.


Timber framing

A timber-framed house is one where substantial

timbers are joined to form an open rigid frame that

supports the roof.

Cruck construction

A cruck consists of a matched pair of curved timbers

(blades) sometimes coming from two matching tree

trunks.

The advantage of a matching pair included the

likelihood that they would distort in the same way.

They were joined at the top, and with a tie-beam

halfway up, to form an “A” shaped frame.

A cruck house would have at least two of these

frames to form the gable ends. They were commonly

16 feet (4.9 m) apart forming one bay.

Additional cruck frames (without the tie-beam) could

be provided in between as required for the length of

the building.

The width of the building (the span) could sometimes

be very large, especially in barns – Leigh Court Barn

in Worcestershire spans over 30 feet (9 m).

The walls were then erected and these could be of

stone, clay or sometimes brick that would usually

conceal the timber.

Alternatively, the walls could be of timber and consist

of sills, posts, rails, and infill panels as for box-frame

construction, thus usually revealing the timber.

Cruck construction was common in Central and

Northern England and in Wales but not in the south

east, and continued to be developed and used for new

building into the 19th Century.

Over 2,000 Cruck framed buildings have been

identified and still stand today, although it is often

difficult to detect them as such from a cursory look,

often because of alterations. The best place to see

them is in the Midlands, especially around Hereford.

Box frame construction

This method was more common and more

widespread.

History of Timber Frame | Section 5


Here, a rectangular frame of sill, posts and a wall

plate was erected on a stone plinth and joined by

mortise and tenon joints.

One frame made each of the two sidewalls of a bay

and one side made each of the gable ends.

As in the case of cruck construction, additional bays

were added to give the required length of the building.

Studding (vertical members) was installed between

the posts. In the south east the studding was relatively

close together, so forming tall narrow openings.

The openings were filled by infill panels to make the

structure weatherproof.

These panels often consisted of wattle and daub.

First, slightly oversize staves were inserted vertically

about 5 to 6 inches (125 to 150 mm) apart into the

rails by springing them into slots. Then lengths of split

oak or hazel or ash were woven horizontally in and out

of the staves to form the wattle.

Next, suitable local wet clay with straw, cow hair or

cow-dung (the daub), was thrown against both sides

of the wattle to form the desired thickness.

It was important that the daub thrown on to one side

met and adhered to the other.

A thin coat of plaster was then applied and

lime-washed or washed with ochre.

The oak weathered naturally to a bronzey grey and

although the distinctive practice of painting them

black existed as early as 1822 it was made almost

universally fashionable in Victorian times.

Therefore the relatively recent ‘magpie’ look would

have been almost unknown before the 1820s.

The ease of breaking the panels led to the

designation ‘breaking and entering’ as a criminal

offence, which is still in use today.

Box frame construction has continued almost to the

present day.

Things have moved on and today we have many

different types of timber frame construction.



History of Timber Frame | Section 5

Here are some other forms of timber frame

construction you should be aware of:

Open panel frame – site insulated

Open frame factory insulated

Open panel frame sheathed internally to receive

external insulation (such as hemp)

Closed insulated panels (shown with party wall)

Cross laminate timber panels (CLT)

Large pre-fabricated panels crane erected

Glulam portal frame with infill panels




Section 6 The Processes Involved

in Timber Frame

6.1 The Processes Involved in Timber Frame 28



Section 6 | The Processes Involved in Timber Frame

6.1 The Processes Involved in Timber Frame

When considering timber frame there are many

different stages you can consider with each one being

an integral part of the whole process.

It all depends from which angle you are looking and

you should have an awareness of the following:

design, manufacture and erect, or

the supply chain

Design, manufacture and erect

Step 1 – Usually the design team is the first to be

involved and they will design and produce the house

(or building) plans to the customer’s requirements.

Alternatively, plans can be adapted to meet timber

frame specifications.

Step 2 – It is common practice these days for the

manufacturer to then work from the plans to develop

computer aided production drawings, optimising

precision in the manufacturing process of the timber

frame kit.

Step 3 – The timber frame kit is then manufactured in

controlled factory conditions by well-trained staff using

the latest in technology in purpose-built buildings. All

components manufactured are coded and labelled.

Step 4 – The completed timber frame kit is thoroughly

checked before being loaded and transported to site.

The kit will be loaded in sequential order for faster

assembly.


The Processes Involved in Timber Frame | Section 6

Step 5 – The timber frame is then erected on-site

following a pre-planned and numbered sequence

from a full set of instructions and drawings that will

be supplied.

Step 6 – The final result: another quality home

produced by timber frame.

The supply chain

There are several key stages involved in the supply

chain, which, in effect, cover the process from the

forest to the finished building.

Forestry – softwood only taken from managed and

sustainable forests

Milling – the wood will be debarked and passed

through the sawmills

Treatment – the wood will normally be treated

using a suitable preservative

Design – an architect will design the building or

previous designs will be used

Engineered components – the design will be

passed to the manufacturer to produce the timber

frame kit

Marketing – the timber frame manufacturers will be

marketing their properties right across the spectrum

to potential customers

Private and public sector house builders/

housing associations – will all be targeted by the

timber frame companies

Construction companies – these are major

players and will be kept informed of timber frame

benefits and advantages

Site erection – the final stage where everything

comes together and the project is completed to the

satisfaction of all

Some ‘green issues’

With growing concern for the environment from global

warming, it is in everyone’s interests to keep energy

demands as low as possible.

Building energy efficient, well-insulated homes

to reduce fuel consumption and running costs

is essential.

However, what many architect/designers/builders do

not realise is that even before a house is built, the

materials used in its construction have a Product

Energy Requirement (PER), which refers to all the

energy that goes into producing and transporting

a product.

Timber has a big advantage here as it is produced

by natural means – sun, water and air – so its

energy requirements are all in the extraction and

transportation of the logs from the forest.

A timber frame wall in a typical three-bedroom

detached family house has a PER of around

7,450 kWh, while a concrete block wall in the same

property requires 1.7 times more energy, with a PER

of around 12,816 kWh.

Timber is also the only renewable structural building

material available, and the majority of timber frame

package companies invest heavily in well-managed

replanting programmes.


Section 6 | The Processes Involved in Timber Frame

Section 7 Drawings and Documents

7.1 Drawings and Documents 32



Section 7 | Drawings and Documents

7.1 Drawings and Documents

With every timber frame kit delivered to site it will have

a full set of drawings relating to it.

You should know what to expect from the

manufacturer in terms of what drawings will be

supplied and how to use and understand them.

A typical list below shows the main headings of

what to expect:

soleplate drawings

timber frame drawings

timber frame details books

nailing schedules

erection checklist

component and delivery schedules

agreed work-scope and specification

Before commencement of work the following

documents must be in place:

risk assessments

health and safety plan

erection programme and delivery plan

craneage plan

Always check you have the full set of drawings you

will be working from and you have access to them.

As always, if in doubt … ask!


Section 8 From Soleplate to Roof

8.1 From Soleplate to Roof 34



Section 8 | From Soleplate to Roof

8.1 From Soleplate to Roof

When erecting timber frame buildings you will follow a

pre-defined method of construction from the soleplate

upwards.

The following checklist – will serve and help you

to understand how the work can be divided into

manageable and meaningful blocks as the building

takes shape.

What you should look for

Two weeks before work starts:

1. A full drawing package

2. Detail booklet and erection instructions

3. Nailing schedule

4. Health and Safety plan

5. Reviewed plans and established build

methodology

6. Pre-start meeting completed

7. Craneage and scaffolding agreed

8. Agreed build programme

One week before kit delivery:

9. Foundations constructed correctly using setting

out drawings

10. Foundations are level

11. Foundations are square and check diagonals

12. Foundations are dimensionally correct

13. Problems reported and rectified

14. Scaffolding completed

15. Access available

16. Crane hard standing agreed

17. Plant to offload available

18. Storage space available

Upon delivery:

19. Check all components delivered

20. Check for damage to kit

21. Report any shortages/damage

22. Sign for goods received


Storage:

23. Keep materials off ground

24. Store panels flat with sheathing side up

25. Keep trusses vertical on bearers at node points or

flat on adequate bearing

26. Keep materials under cover but maintain

ventilation

During site erection:

27. Care is taken to avoid damage

28. Follow drawings and details

29. Temporary bracing is fitted

30. Floors are not overloaded by materials

31. Safe systems of work are implemented

32. Panels are correctly nailed and secured

33. Work is progressed systematically, floor-by-floor

34. Tidy up as you go

35. All work is completed per level

(do not drop back later)

36. Scaffolding progresses well ahead and safely

(do not modify)

From Soleplate to Roof | Section 8



Checks upon completion of erection:

Frame checks:

37. Frame anchored to slab

38. All damage repaired

39. Cavities plumbed to suit external cladding

and cavity width

40. Structural shell handed over and signed for

Wall checks:

41. DPC’s are under ALL ground floor walls in contact

with slab

42. Panels are right way up, in correct position and

plumb to tolerance

43. All joints are tight

44. All fixings as per schedule

45. Breather membrane is lapped and repaired,

if necessary

46. Multiple studs under point loads

47. All partitions are plumb

48. Locating plate and head binder plate fitted

if required

Floor checks:

49. Joists in accordance with design drawings

50. Joists have adequate bearing

51. Joists are correctly nogged or blocked out

52. Joists nailed with tight connections as

per schedule

53. Joists are tight and even


54. Stair trimmed correctly

55. Notching or drillings ONLY as per detail

56. Joist hangers fully nailed

57. No excessive loads applied, i.e.

plasterboard stacks, etc.

Roof checks:

58. Trusses correct spacing and plumb to tolerance

59. All trusses have clips fitted to wall head

60. Trusses are correctly braced

61. Loose infill tight and well connected

62. Girder trusses are bolted or well nailed

63. Multiple studs fitted under point loads

64. Locating plate and head binder plate fitted

if required

65. Soffit supported with noggings, if required

66. Valley boarding fitted

67. Ladder sections connected to spandrel panels

68. Roof bracing connected to spandrel panels

69. All shoe ironmongery fitted and fully nailed

From Soleplate to Roof | Section 8




Section 9 Fire Resistance

9.1 Fire Resistance 40



Section 9 | Fire Resistance

9.1 Fire Resistance

All buildings must provide the degree of fire

resistance as set out in the Building Regulations.

The fire resistance of timber frame is achieved

through a combination of:

the internal plasterboard lining

the timber structure

the insulation

cavity barriers

Use of plasterboard

Plasterboard has excellent fire resistant properties

and ‘absorbs’ heat as part of a chemical reaction,

which serves to protect the timber beneath.

Increased fire resistance can be achieved by using

thicker plasterboard or multiple layers with joints

staggered, or by using special fire resisting boards.

Plasterboard also meets the requirements for Class 0

and Class 1 internal surface linings.

Fixing plasterboard

Correct plasterboard fixing is essential to achieve the

desired fire performance. If the fixings are inadequate

the boards will fail early.

Fixing specifications depend upon type of fixing used,

plasterboard nails or drywall screws. Always refer to

manufacturers’ instructions.

In general, nail fixings should be at maximum

150 mm centres and drywall screw fixings at

230 mm or 300 mm centres, depending on location

Drywall screws reduce the risk of ‘nail popping’

in walls and ceilings resulting from moisture

movement in the timber

Generally

Fire resistance requirements for structural frame and

intermediate floors in dwellings (excluding ground

floors and party walls and floors) are:

houses up to two storeys require 30-minute fire

resistance for walls and ‘modified’ 30-minute fire

resistance for floors

houses of three storeys require full 30-minute

fire resistance

dwellings over three storeys (up to 18 m) require

60-minute fire resistance

Fire resistance requirements for party walls and

floors between dwellings:

party walls between dwellings require 60-minute fire

resistance

party floors between most dwellings require

60-minute fire resistance

For buildings, which are not dwellings, the fire

resistance requirements depend upon:

the type of building (purpose group)

location (national regulations vary)

height

floor area

volume

escape distances

Walls and partitions

Generally, 30-minute fire resistance is provided by one

layer of 12.5 mm plasterboard and 60-minute by two

layers of 12.5 mm plasterboard.

However, most party walls also have to provide

acoustic performance and the design of timber frame

party walls takes into account both requirements.

Floors

30-minute fire resistance is generally provided by:

38 mm (min.) breadth solid timber joists at

600 mm centres

any structurally suitable floor decking (15 mm min)

12.5 mm plasterboard ceiling fixed to joists

(and noggins at board edges) with joints taped

and filled

plasterboard density to suit manufacturers’

recommendations

60-minute fire resistance is generally provided by:

38 mm (min.) breadth solid timber joists at

600 mm centres

15 mm (min.) T&G plywood, OSB or chipboard

floor decking


Fire Resistance | Section 9

not less than 30 mm plasterboard laid

perpendicular to joists with joints staggered, joints

in outer layer taped and filled. Edge joints in outer

layer supported by noggins where required

plasterboard density to suit manufacturers’

recommendations

Note

Fire integrity of engineered wood joists will be

verified by component manufacturer.

Cavity barriers

Cavity barriers are used within cavities to prevent

fire spread.

They can be:

rigid – preservative treated timber battens, or

non-combustible board or flexible types; based on

mineral wool

Cavity barriers are installed in cavities at:

party walls

party floors

verge or ceiling level

around openings, doors, windows, extracts, etc.

in Scotland, additional cavity barriers are required

at eaves and vertically at centres defined in the

regulations. You should also be aware of a Supalux

(or similar) clad boxed eaves closer


Section 9 | Fire Resistance


Section 10 Acoustics

10.1 Acoustics 44



10.1 Acoustics

Floor impact and airborne noise is another important

consideration when installing timber floors. Regardless

of how they are fitted, good quality timber floors will

create impact sound.

Walls and floors within dwellings are required to

restrict the transfer of sound as well as fire.

The requirements are based on Part E (England and

Wales) and Part H (Scotland).

Robust standard details have been developed to

comply and exceed legislative change.

Example of acoustic measures that can

be installed:

Workmanship

Testing has shown that the standard of workmanship

is crucial in ensuring that the expected acoustic

performance is met.

Effective and vigilant site supervision is critical to

ensure adherence to design and material guidance,

is achieved

Maintaining structural separation by correct

installation of insulation, plasterboard and floating

floors is essential

Sacrificial service zones are recommended to avoid

penetrating wall and floor build ups

Timber frame walls within dwellings rely on mass,

separation and air cavity for acoustic performance.

The ‘Standard’ wall

Two separate stud frames

Absorbent blanket (insulation) between the studs to

each wall

Minimum 32 mm plasterboard linings on room faces

250 mm cavity width between linings

The wall is incorporated as a Robust Detail (RD), in

England and Wales

This wall can incorporate sheathing to both leafs

within the cavity side for stability

Timber floors within dwellings rely on mass,

de-coupling and air cavity depth for acoustic

performance.

The ‘Standard’ floor for flats

Minimum 220 mm timber joist depth

An absorbent layer of insulation between joists

Plasterboard ceiling fixed to resilient bars (British

Gypsum RB1 or equivalent)

Structural floor deck fixed to joists

A floating platform floor above the structural deck

The floor is incorporated as a Robust Detail (RD)

for England and Wales

Flanking noise

This is controlled by the effectiveness of junction

details and is critical to the performance of party walls

and floors by:

cavity separation

stagger sheeting junctions

simple construction

perimeter isolation strips to floating floors

site control and supervision

Section 10 | Acoustics


Section 11 Differential Movement

11.1 Differential Movement 46



11.1 Differential Movement

Why it happens

Timber is typically installed at 20% moisture content.

This reduces to around 10% in the heated building.

As timber dries out, its cross-section shrinks and the

structure settles.

Cladding materials also change; clay bricks expand,

blocks and calcium silicate bricks shrink – but not in

tandem with the timber!

It is good practice to pre-load the timber frame

structure with roof tiles and internal sheeting materials

prior to the installation of the masonry cladding, within

structural limits.

The implications

Any material or component attached to the timber

frame structure which overhangs or projects through

masonry cladding must have an adequate gap

beneath it to allow differential movement to take place

without damage to the structure or the cladding.

Gaps should be filled with a compressible sealant.

Allowance needs to be made at:

window sills

roof verges and eaves

where attached cladding, e.g. timber or boarding,

overhangs brickwork

flues and chimneys

overflow pipes

traditionally built stair cores

Vertical shrinkage will be reduced by:

using engineered wood joists (both types)

ensuring detailing is correct to allow for settlement

ensuring adequate gaps are left to take up the

downward movement of the frame

keeping timbers as dry as possible

Note

Gaps should be filled with flexible sealant,

to allow settlement to occur.

Gap sizes

(Any figures used below should only be taken as

estimates.)

The whole subject of tolerances is constantly reviewed

and therefore the values in these workbooks should

only be used as guidelines.

For a conventional platform frame up to three storeys

with concrete ground floor 200 mm intermediate floor

joists installed at 20% moisture content, drying down

to 10%, the recommended gaps should be in the

region of:

You should have picked up that:

the higher the building the greater the gap and

the largest gaps are always at the top

Verges and eaves

At the eaves the roof space ventilation openings are

normally equivalent to a continuous opening of a

minimum 10 mm each side for roof pitches greater

than 17º.

Section 11 | Differential Movement


Differential Movement | Section 11

Sills

Around the sills brick cladding is normally coursed

to the head of the openings using an adjustable sill

detail such as tiles or sloping brick:


Section 11 | Differential Movement

Section 12 Building Insulation

12.1 Building Insulation 50



Section 12 | Building Insulation

12.1 Building Insulation

This is not normally part of the timber frame erectors

responsibility but should you become involved then

you must be aware of the following.

When fitting and/or applying insulation material

within a building the correct PPE must be worn.

Such as:

all in one paper suit

gloves

goggles

mask

hat

The main factors for you to consider are:

The thickness of the insulation

This will be defined and explained on the construction

issue drawing. The thickness may vary according to

location and building regulations.

The position of the insulation

This is normally against:

all external walls

all floor areas

all ceiling voids

But is predominantly site specific so always check the

construction issue drawing for further information.

Fitting the insulation

The insulation will need to be fitted tightly between the

studs and/or joists. But if the friction will not hold it in

place you will have to use other fixing methods such

as:

staples or PVA glue to maintain an even and gap

free coverage

if these fixing methods are not on the drawings

then check with your supervisor if it is acceptable

Points to note

There must be no gaps in the insulation and care

must be taken especially around areas where

services run through walls

When fitting insulation in the ceiling areas make

sure that there is sufficient overlap between the

insulation and the wall panels to ensure no cold

bridging occurs but at the same time be careful not

to block the roof ventilation

Tick the box when you have completed the following tasks:

Correctly insulated and fitted the appropriate material to:

All external walls

All floor areas

All ceiling voids

Around services through walls

Activity

Section 13 Vapour Control Layers

13.1 Vapour Control Layers 52



Section 13 | Vapour Control Layers

13.1 Vapour Control Layers

In timber frame buildings, it is essential to stop

and control the moisture generated inside a

building from escaping into the timbers.

To prevent this happening a Vapour Control Layer

(VCL) is applied.

A VCL is fitted on the WARM SIDE of the

insulation, and applied beneath the Plasterboard

lining as shown.

If required – you should be able to correctly master

this skill.

The VCL should run from:

the full height of the ceiling (but allowing for a lap

to go under the ceiling plasterboard) down to the

soleplate

Main considerations before fitting the VCL are:

the VCL should only be fitted when the moisture

content in the timber frame is below 20%

– this can only be achieved by the use of a

correctly calibrated moisture meter

laps in the VCL membrane must be at least

100 mm

the VCL membrane must be inserted and returned

into all reveals, together with head and sills of all

openings

check for any tears or gaps in the membrane and

repair any found with the correct adhesive such as

PVC tape

make sure that where any services pass through

the membrane that it is adequately sealed

afterwards

Vapour barriers

Water vapour from cooking, washing and bathing,

etc. can penetrate plasterboard. Vapour barriers are

installed to restrict this water vapour from reaching

the insulation and timber frame with the obvious

consequences.

It is important that the vapour barrier is not

torn or punctured.

It is essential for the durability of the structure by

keeping the timber dry.

In most timber frame walls, this is achieved

through a combination of:

a drained and vented cavity between the frame

and the cladding

a protective breather membrane on the cold side

of the insulation and applied to the outer face of

the sheathing

a VCL on the warm side of the insulation, applied

beneath the plasterboard lining


Vapour Control Layers | Section 13

The VCL may be:

a separate polythene sheet or vapour check

plasterboard

The VCL maintains continuity over the wall

surface and serves as a control layer for moisture:

joints should occur at studs with 100 mm minimum

overlap

ensure insulation is tight to the VCL

do not leave any air gaps

Tick the box when you have completed the following actions correctly and your supervisor is

satisfied with your work.

Fit and install VCL – correctly

The VCL should ONLY be fitted when the moisture content in the frame is below 20%

(This can only be achieved by the use of a correctly calibrated moisture meter)

Moisture content checked and gave a reading of: %

Lapped the VCL correctly and by at least 100 mm

The VCL membrane inserted and returned into all reveals, head and sills of all openings

Checked for any tears or gaps in the VCL and repaired any found with the correct

adhesive (such as PVC tape)

Make sure that where any services pass through the VCL it is adequately sealed

Activity



Air barriers

The air barrier is normally fitted prior to plaster boarding

(and replaces the vapour barrier), but certain areas

of the air barrier may need to be fitted as part of the

erect package as a continuous barrier is required to be

jointed to the vapour control/air barrier.

Air barriers are designed to completely seal the

structure so that the number of air changes within the

dwelling is kept to a minimum; usually below 10 air

changes per hour but sometimes as low as three air

changes per hour.

The air barriers form a continuous envelope behind

the plasterboard and will be linked across the floor

zone and at ceiling level of the uppermost storey of

the dwelling.

Where the different layers of the air barrier are linked

they must be taped together as must any perforations

for services, such as a waste pipe exiting the structure

i.e. the waste pipe will need to be ‘taped’ to the

external air barrier.

The air barrier illustrated in the photo below was

installed during the erect works across the floor

joist zone.

A strip off air barrier is taken:

down the internal face of the external panels

over the top of the panel

up the face of the cavity ‘encasing’ the joists

back up the face of the next level of panels

when the air barrier is completed by following

trades the air barrier installed by the erect team

across the floor zone will be taped to seal the main

air barrier

this totally ‘encloses’ the floor zone


Health and safety on site

As a team member working with others you must be

aware of Health and Safety implications on site,

you will be expected to promote a good Health and

Safety culture.

You need to:

ensure that you comply with method statements

and risk assessments

ensure you take responsibility and care of yourself

and colleagues

ensure that you sign in each day

comply and conform to instructions

ensure that you are trained appropriately to

complete the task you are set

ensure that plant and equipment is used and

maintained correctly

communicate with others and report any failures

or issues

not interfere with plant or equipment and above all

set a good example

Vapour Control Layers | Section 13



Section 14 Final Review

14.1 Final Review 58

14.2 Learner Feedback Form 60



14.1 Final Review

On behalf of the STA and CITB we hope you have

enjoyed this workbook on Knowledge Skills.

This is now the benchmark for everyone at silver level

in the industry.

As a reminder we have included below a simple

checklist for you in this final review. When arriving

on-site you should now know what key points to

consider before you start work.

Here are a few we hope you will remember:

general knowledge of timber from the forest

to the wood

general knowledge of timber frame

benefits of timber frame

knowledge from the soleplate to the roof

knowledge of key areas such as fire resistance,

acoustics, differential movement, building insulation

and vapour control layers

Most importantly, once you have been assessed on

these Knowledge Skills in combination with the silver

level Health and Safety Skills and Practical Skills

training, you will have reached a level of qualification

the industry wishes all timber frame erectors to

achieve over the next few years.

Congratulations!

In addition, from a combination of this training and the

knowledge and experience you have already acquired,

you are well on your way to reaching gold level, which

is the highest level of qualification available to timber

frame erectors in the UK.

We also hope that you will feel sufficiently pleased

with your training experience to encourage other

colleagues to use this training and to continue their

own personal development to become as similarly

qualified as yourself.

For most of us, our home is our largest expense and

we expect it to be built to the highest standards by

well-trained and suitably qualified people. By using

these workbooks, we, as an industry, can now provide

you with the opportunity to achieve this goal. Also by

having a qualified workforce we can compete with the

rest in quality and workmanship.

Thank you for taking part in this training experience

and we hope you will enjoy a successful and satisfying

career in our timber frame industry.

Timber frame erector

training workbooks

These workbooks have been prepared by the

Structural Timber Association, in conjunction with

CITB, on behalf of the industry.

STA and CITB operates a continuous improvement

policy and would therefore be very grateful to receive

any review comments for further editions – you will

find a learner feedback form on the next page.

Thank you.

Section 14 | Final Review


Structural Timber Association

Head Office

The e-Centre

Cooperage Way Business Village

Alloa

Clacks

FK10 3LP

Tel: 01259 272140

Fax: 01259 272141

Website: www.structuraltimber.co.uk

Or

National Specialist Accredited Centre

CITB

Unit 1 and 2

674 Melton Road

Thurmaston

Leicester

LE4 8BB

Tel: 0300 456 5561

Fax: 0300 456 5562

Email: [email protected]

The production of these workbooks has been

supported financially by CITB and, without their

help, would not have been possible. The industry

acknowledges this fact and is extremely grateful

to them.

Whilst the STA/CITB have had these workbooks

prepared to provide guidance on timber frame

construction, the STA/CITB accepts no liability

and offers no warranties in relation to them and

their contents to the fullest extent applicable law

can exclude such liability. Users therefore are

required to satisfy themselves as to the suitability

of the contents of this guidance for their specific

intended purpose

Structural Timber Association/CITB 2013.

Final Review | Section 14


14.2 Learner Feedback Form

The STA and CITB would appreciate it if you could

take the time to complete the following questions as

this will enable them to ensure that future training and

training materials are of good quality and relevant

to the participant. Please tell us what was good as

well as bad about your training and any ideas on how

you would like to see it develop or improve. We have

included comment boxes for this purpose.

Name:

*not mandatory

Company:

*not mandatory

Level of award: Silver Knowledge Skills

Please indicate your score of each section by ticking the appropriate box – 1 being the lowest through to 5

being the highest.

Lowest Highest

Sections: 1 2 3 4 5

What is Timber Frame?

Comments:

Benefits of Timber Frame

Comments:



History of Timber Frame

Comments:

The Processes Involved in Timber Frame

Comments:

Drawings and Documents

Comments:

From Soleplate to Roof

Comments:




Fire Resistance

Comments:

Acoustics

Comments:

Differential Movement

Comments:

Building Insulation

Comments:

Vapour Control Layers

Comments:



Please tell us what was most helpful during this training – again there are tick boxes rating from 1 to 5.

Lowest Highest

1 2 3 4 5

Assessor

Comments:

Workbooks

Comments:

On-site tuition/advice

Comments:

Support of Organisation

Comments:


Overall how did you feel the process helped you in

gaining knowledge and skills at the required level?

Comments:

Many thanks for taking the time to fill in this learner feedback form.

Please return the completed form to your Assessor for forwarding to the STA or alternatively if you wish

send it direct to:

STA

Education and Training Section

The e-Centre

Cooperage Way Business Village

Alloa

FK10 3LP
