Part of Historic Environment Scotland

Conservation of Timberwork

Dates: 19/2/18 - 19/3/18
Days of the week: Monday
Total hours: 47
Taught hours: 22
On-site instruction: 10
Off-site instruction: 12

Description

Uncover one of the essential elements of traditional Scottish building construction: the use of timber from the medieval period to the present.

This module provides a technical overview of timber as a building material – whether in an interior or exterior, structural or ornamental context. Timber’s fundamental physical properties in relation to natural weathering and decay processes are studied, as is its resilience to man-made damage or interference.

You will explore the use of timber in a wide range of traditional Scottish structures, from coarse cruck-roof structures to fine internal decoration. As well as timber’s predominant use as structural material, it is the material of choice for common building features such as windows, door sets and staircases.

Discover the many challenges faced in the repair and conservation of timber – particularly how to source suitable and sustainable replacement material. You will find out how to plan repairs in line with conservation principles, from initial survey and diagnosis to on-site installation. An important aspect of this is learning how to identify timber types, to enable the matching of replacement material.

Entry requirements

Individual modules are open to anyone with an interest in the subject matter. Applicants for the Advanced Professional Diploma should have a relevant degree or professional experience.

Classes, lectures and presentations

  • Scottish Timberwork and Timber Types
  • Structural Timberwork
  • Finishing Joinery and Repairs
  • Decay Mechanisms in Timber
  • Timber – Repair, Conservation and Maintenance
  • Timber – Health and Safety Issues

Potential site visits

  • Crannog Centre, Loch Tay
  • Auchindrain Township
  • Great Hall, Stirling Castle
  • Hill House, Helensburgh
  • John Knox House, Edinburgh
  • Huntly House, Edinburgh
  • City Chambers, Glasgow
  • St Vincent Street Church, Glasgow
  • Window or joinery restoration workshop

Hands-on workshop/lab activities

Traditional joinery techniques – e.g. cutting splices, joints, decorative carving

Content

Scottish timberwork traditions

Historic background and documented origins of use from medieval period to present

Timber types

  • Hardwoods – e.g. oaks, beech, elm, sycamore, elm, birch, lime
  • Softwoods – e.g. spruces, pines, larches, Douglas fir
  • Nature of ancient and modern softwoods
  • Sourcing of Scottish timbers
  • How to recognise and identify species, heartwood, sapwood and so on
  • Material characteristics and mechanical properties
  • Timber use – reflecting properties, grain and so on (especially in regard to structural vs finishing timber)
  • Grading – assessment, processing

Key structural elements

  • Roof rafters and trusses
  • Sarking, wall plates, gutter soles
  • Cupolas, roof lights and hatches
  • Floors and joists – wood types, loading, decorative finishes, shrinkage, cupping
  • Dormers
  • Pien ends
  • Bressumers and safe lintels
  • Armatures for ornate plaster
  • Lath, dooks and strapping for flat plaster
  • Timber partitions

Key joinery elements (and patterns of wear, decay or failure)

  • Windows and shutter sets
  • Doors, door sets and porches
  • Staircases, balustrades and rails
  • Interior ornamental details – e.g. mouldings, fireplaces, panelling, architectural features
  • Exterior ornamental details – e.g. cornices, bow/bay windows, porticoes, bargeboards, finials
  • Cladding and framing
  • Fixings, hardware and ironmongery

Decay mechanisms

  • Timber fungi (wet rots, dry rot, soft rot) – spore germination, moisture requirements, environmental conditions, growth and decay rates
  • Insect attack – e.g. beetles, woodworm, weevils, wasps, bees, ants, woodlice
  • Environmental controls and eradication of rot and infestation
  • Role of maintenance in limiting timber decay
  • Effect of sunlight – i.e. damage caused by UV radiation
  • Mechanical damage – e.g. from handling and cleaning, inappropriate repairs or inadequate maintenance, alterations, vandalism
  • Environmental damage – warping, splitting and discolouration due to excessive heat and changes in temperature and humidity
  • Reaction of timber to chemicals (e.g. acids) or metals
  • Water damage – e.g. leaks, spillages, floods
  • Fire and smoke damage

Repair, conservation and maintenance

  • Site practice and work sequence
  • Best practice in specifying repair works – determining significance based on background research and site survey
  • Use of dendochronology, moisture metering and other survey techniques
  • Assessment of past interventions (alterations, repairs, maintenance)
  • Determining scope and methods of proposed repairs
  • Selection of replacement timber to match
  • Structural work – e.g. intervention/reinforcement (settlement and subsidence), use of steel
  • Importance of correct joints and fixings
  • Treatments – replacement, patching/filling/epoxy or acrylic resin injection and other partial repair or consolidation techniques
  • Timber preservation treatments
  • Pest management techniques
  • Upgrading doors to meet fire regulations
  • Dismantling and re-erection – risks and practical considerations
  • Conservation of wood in marine environments
  • Finishing and surface repair work – paint, polishes, stains, varnishes and other protective finishes

Health and safety issues

  • Handling, dust and toxicity considerations – e.g. lead paints, biocide treatments
  • Caustic paint strippers
  • Working at height