Timber conservation and repairing timber frames


Overview
This intermediate level standard provides the learner with the underlying knowledge to repair and maintain traditional timber frame structures.

CITB has developed this standard in discussion with industry

Duration

Minimum 2 days of 6 learning hours

Purpose/Scope

This standard will provide the attendee with the underlying knowledge to repair and maintain traditional timber frame structures.

The scope of this standard covers:

  • personal protective equipment (PPE)
  • respiratory protective equipment (RPE)
  • timber conservation techniques
  • historical periods
  • factors causing damage
  • types of damage
  • building conservation
  • “signature marks”
  • recording
  • repairs
  • repair or replacement
  • re-alignment
  • scribing
  • manual handling
  • scarfing

Occupational relevance

Training delivered against this standard would be relevant to the following occupational groups:

  • operative and craft

Candidate pre-requisites

It is expected that the candidate will be employed within the oak frame industry or have significant relevant carpentry experience.

Instruction/Supervision

As a minimum, course instructors must be able to demonstrate that, in relation to this standard, they have:

  • a train the trainer or instructional techniques course certificate
  • successfully completed training to this standard
  • at least 10 years relevant industrial experience
  • a verifiable CV

Delivery

Delivery may be in an on or off the job environment.

All materials and equipment must be of a suitable quality and quantity for candidates to achieve learning outcomes, and must comply with relevant legislation.

The class size and candidate/instructor ratio must allow training to be delivered in a safe manner and enable candidates to achieve the learning outcomes.

The following delivery methods may/may not be used in the delivery of this standard:

  • classroom
  • workshop

This standard is considered to contain 51 per cent or more theoretical learning.

This standard is considered to be set at an intermediate level

Assessment

For the successful completion of training, candidates must complete an end of course practical assessment and knowledge test that measures the learning outcomes and has a pass or fail criteria.

Quality assurance

Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard. 

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the Training Standard. 

Approved training organisations will be required to present information on records of training and assessment upon request to CITB for desk based analysis. They will also be visited annually by the CITB quality assurance team.

Renewal/refresher

There is no mandatory renewal or recommended refreshment requirements for this standard.

Approval date

April 2019

Review cycle

Either on request or in 3 year(s) from approval date.

Learning outcomes

The candidate will be able to: Additional guidance to support learning outcome

This module will include a site visit with a specialist in timber conservation techniques, which will be conducted in one of a number of suitable venues for example:

  • Avoncroft Museum
  • St Fagans Museum of Welsh Life
  • Weald & Downland Museum
  • Cressing Temple Barns

Or similar venue where major conservation work has taken place.

Identify timber buildings of different historic periods

Explain how it is possible to identify the age of buildings from the following evidence;

  • timber size and proportion
  • building shape and form
  • joint repertoire
  • tool marks
  • timber conversion methods
  • decoration

Identify factors causing damage to timber building structures

Describe how damage can be caused to timber structures by

  • material defect in the original timbers
  • poor original design
  • fungi
  • insects
  • weather
  • subsidence or seismic activity
  • general dilapidation or lack of upkeep
  • fire
  • intentional interventions
  • unintentional interventions

Explore the range of types of damage which can occur within a timber structure

Identify the following types of damage

  • wet rot
  • dry rot
  • wood-boring beetle infestation
  • structural deformation caused by wind, subsidence, excessive loadings etc
  • removal or alteration of timber elements, fixings, changes in loadings, changes in adjacent buildings etc

Look into the historical, moral and aesthetic arguments surrounding building conservation

Explain the arguments surrounding the repair and conservation of historic and heritage buildings.

Explain the importance of preserving “signature marks” and timber surfaces

Describe the significance of tool marks in determining the timber conversion and construction method.

Debate the use of aggressive sanding or sandblasting to remove modern surface finishes.

Record a historic timber building and make an analysis of the load bearing structure

Using techniques including

  • measuring
  • scale drawing
  • photographic recording

Explain how to “read” the timber frame and to determine the intended and actual load paths.

Investigate a range of repair methodologies for individual timber repairs

Explain the use of

  • traditional jointed repairs
  • through-bolted repairs
  • modern adhesives
  • laminate repairs
  • steel flitch plates
  • carbon reinforced plastic (CRP) repairs
  • glass reinforced plastic (GRP) repairs

Investigate the use of materials and elements which have been detrimental to the survival of timber frames

Describe how the common past use of

  • cement
  • mild steel
  • non porous sealants and paints

have damaged timber frames.

Repair or replace timbers

Explain the criteria that may influence the choice to either replace or to repair a timber member.

Investigate the re-alignment of timber frames as a means to re-establish original structural connections and load paths

Describe how distortions and movements to the building’s shape can alter load paths and put strain on elements that are not designed to accept that new load.

Investigate appropriate scribing methods when working on distorted in situ timbers

Explain how to set up datum lines and cut accurate repairs or replacements to in-situ frames.

Select, fit and use the appropriate Personal Protective Equipment (PPE), store, maintain and report defects in training and work equipment

Will be able to Identify the correct PPE and understand storage, maintenance and employer damage reporting procedures for:

  • safety footwear
  • safety gloves
  • safety eyewear
  • RPE/dust masks
  • knee protectors
  • hearing protectors
  • hard hats
  • high visibility clothing

Safely move materials to workplace observing safe manual handling techniques

Explain health & safety requirements for manual handing.

Scarf a new end on a post or beam.

Select timber of appropriate species, dimension and seasoning.

Make a scarf joint using variety of techniques including:

  • traditional jointed repair
  • glued repair
  • glued and bolted
  • GRP or CRP repair

Explain how the use of the timber within the structure determines the appropriate method of repair.

Additional information

Recommended reading:

OAK FRAMED BUILDINGS – Rupert Newman

FRAMING ROOFS – The best of Fine Homebuilding

BARNS OF RURAL BRITAIN –Graham Hughes ISBN 0-906969-36-0

TIMBER FRAME – Ted Benson ISBN 1-56158-281-6

TIMBER FRAMED BUILDINGS – John Bailey Bed Bucks and Cam Historic Building Research Group

CONSERVATION OF TIMBER BUILDINGS – F. W. B. Charles ISBN 0-7487-0376-4

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