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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
5Timber Frame Erector Knowledge Skills Workbook
1.1 The Timber Frame Erector Training Programme 6
6 Timber Frame Erector Knowledge Skills Workbook
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
7Timber Frame Erector Knowledge Skills Workbook
8 Timber Frame Erector Knowledge Skills Workbook
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
9Timber Frame Erector Knowledge Skills Workbook
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
10 Timber Frame Erector Knowledge Skills Workbook
Section 2 | Aims and Objectives of Training
11Timber Frame Erector Knowledge Skills Workbook
Section 3 What is Timber Frame?
3.1 What is Timber Frame? 12
11Timber Frame Erector Knowledge Skills Workbook
12 Timber Frame Erector Knowledge Skills Workbook
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?
13Timber Frame Erector Knowledge Skills Workbook
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.
14 Timber Frame Erector Knowledge Skills Workbook
Section 3 | What is Timber Frame?
15Timber Frame Erector Knowledge Skills Workbook
Section 4 Benefits of Timber Frame
4.1 Benefits of Timber Frame 16
15Timber Frame Erector Knowledge Skills Workbook
16 Timber Frame Erector Knowledge Skills Workbook
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
17Timber Frame Erector Knowledge Skills Workbook
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.
18 Timber Frame Erector Knowledge Skills Workbook
Section 4 | Benefits of Timber Frame
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.
19Timber Frame Erector Knowledge Skills Workbook
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
20 Timber Frame Erector Knowledge Skills Workbook
Section 4 | Benefits of Timber Frame
Section 5 History of Timber Frame
5.1 History of Timber Frame 22
21Timber Frame Erector Knowledge Skills Workbook
22 Timber Frame Erector Knowledge Skills Workbook
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.
23Timber Frame Erector Knowledge Skills Workbook
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
24 Timber Frame Erector Knowledge Skills Workbook
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.
Section 5 | History of Timber Frame
25Timber Frame Erector Knowledge Skills Workbook
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
26 Timber Frame Erector Knowledge Skills Workbook
Section 5 | History of Timber Frame
27Timber Frame Erector Knowledge Skills Workbook
Section 6 The Processes Involved
in Timber Frame
6.1 The Processes Involved in Timber Frame 28
27Timber Frame Erector Knowledge Skills Workbook
28 Timber Frame Erector Knowledge Skills Workbook
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.
29Timber Frame Erector Knowledge Skills Workbook
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.
30 Timber Frame Erector Knowledge Skills Workbook
Section 6 | The Processes Involved in Timber Frame
Section 7 Drawings and Documents
7.1 Drawings and Documents 32
31Timber Frame Erector Knowledge Skills Workbook
32 Timber Frame Erector Knowledge Skills Workbook
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!
33Timber Frame Erector Knowledge Skills Workbook
Section 8 From Soleplate to Roof
8.1 From Soleplate to Roof 34
33Timber Frame Erector Knowledge Skills Workbook
34 Timber Frame Erector Knowledge Skills Workbook
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
35Timber Frame Erector Knowledge Skills Workbook
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
36 Timber Frame Erector Knowledge Skills Workbook
Section 8 | From Soleplate to Roof
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
37Timber Frame Erector Knowledge Skills Workbook
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
38 Timber Frame Erector Knowledge Skills Workbook
Section 8 | From Soleplate to Roof
39Timber Frame Erector Knowledge Skills Workbook
Section 9 Fire Resistance
9.1 Fire Resistance 40
39Timber Frame Erector Knowledge Skills Workbook
40 Timber Frame Erector Knowledge Skills Workbook
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
41Timber Frame Erector Knowledge Skills Workbook
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
42 Timber Frame Erector Knowledge Skills Workbook
Section 9 | Fire Resistance
43Timber Frame Erector Knowledge Skills Workbook
Section 10 Acoustics
10.1 Acoustics 44
43Timber Frame Erector Knowledge Skills Workbook
44 Timber Frame Erector Knowledge Skills Workbook
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
45Timber Frame Erector Knowledge Skills Workbook
Section 11 Differential Movement
11.1 Differential Movement 46
45Timber Frame Erector Knowledge Skills Workbook
46 Timber Frame Erector Knowledge Skills Workbook
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
47Timber Frame Erector Knowledge Skills Workbook
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:
48 Timber Frame Erector Knowledge Skills Workbook
Section 11 | Differential Movement
Section 12 Building Insulation
12.1 Building Insulation 50
49Timber Frame Erector Knowledge Skills Workbook
50 Timber Frame Erector Knowledge Skills Workbook
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
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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
53Timber Frame Erector Knowledge Skills Workbook
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
54 Timber Frame Erector Knowledge Skills Workbook
Section 13 | Vapour Control Layers
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
55Timber Frame Erector Knowledge Skills Workbook
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
56 Timber Frame Erector Knowledge Skills Workbook
Section 13 | Vapour Control Layers
Section 14 Final Review
14.1 Final Review 58
14.2 Learner Feedback Form 60
57Timber Frame Erector Knowledge Skills Workbook
58 Timber Frame Erector Knowledge Skills Workbook
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
59Timber Frame Erector Knowledge Skills Workbook
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
60 Timber Frame Erector Knowledge Skills Workbook
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:
Section 14 | Final Review
61Timber Frame Erector Knowledge Skills Workbook
History of Timber Frame
Comments:
The Processes Involved in Timber Frame
Comments:
Drawings and Documents
Comments:
From Soleplate to Roof
Comments:
Final Review | Section 14
62 Timber Frame Erector Knowledge Skills Workbook
Section 14 | Final Review
Fire Resistance
Comments:
Acoustics
Comments:
Differential Movement
Comments:
Building Insulation
Comments:
Vapour Control Layers
Comments:
63Timber Frame Erector Knowledge Skills Workbook
Final Review | Section 14
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:
64 Timber Frame Erector Knowledge Skills Workbook
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
Section 14 | Final Review