Timber Frame Information:

Timber frame manufacturing methods.

1. Other structural elements.
   Floors and roofs in timber frame construction are similar to those used in masonry construction. Ground floors are either an insulated concrete slab or suspended types - either precast concrete or timber. Intermediate floors are either prefabricated floor cassettes or site-built floors. Floor joists are normally at 400, 480 or 600 mm centres, and are of a constant depth to allow wall panels to be all the same height. In platform frame, the floor joists are supported directly on the top plate of the wall panels or on a head binder. Head binders are used to connect wall panels together and to support floor joists that are not coincident with stud positions. An additional header joist is used around the perimeter of the building to support the upper wall panels and at party walls also to maintain fire and acoustic performance.
   
   
2. Trussed rafter roofs should comply with BS 5268 - 3. They are fixed directly to the wall panels, or to head binders if the trusses do not coincide with stud positions.
   Party floors are constructed with timber providing the structural element and various combinations of ancillary components contributing to the required fire and acoustic performance.
   
   
3. Timber frame buildings fire resistance.
   
   
   
4. Services.
   The provision for services is particularly simple in timber frame construction, because they can be run in the cavity between the studs of the wall panel. If wet services are run in the external wall, they should be on the warm side of the insulation to avoid condensation from the pipes in the external wall. Care must be taken to seal the vapour control layer around penetrations. If there is a high degree of servicing required in an external wall (or party wall), the provision of a service cavity formed by using battens fixed to the studs between the vapour control layer and the plasterboard lining may be considered.
   Guidance on services in timber frame is given in Services in timber frame construction - Guidance for a defect-free interface, prepared jointly by TRADA Technology and BSRIA.
   
5. Preservative treatment.
   The need for preservative treatment depends on the durability of the timber used and an assessment of the risk of decay or insect attack. In timber frame this can be divided into two basic categories:
   Treatment essential:
   Sole plates
   Bottom members of loadbearing wall frames or joinery resting directly on the dpc
   Timber cavity barriers in external cavity walls(also to be protected by separate dpc)
   Timber in cold design flat roofs
   Cladding fixing battens
   Tiling battens.
   
   Treatment recommended as insurance:
   Joists in suspended timber ground floors
   Load bearing timber external wall frames.
   
   
6. The recommendation in the Building Regulations (England and Wales) that material exposed to and likely to be adversely affected by moisture implies that cladding with slightly durable (or not durable) species of wood requires preservative treatment.
   
   
7. Visit the mis-spelt site for the interesting front page.
   
   
8. Treatment of individual members in the manufactured components listed above is most often carried out using micro-emulsion based wood preservatives. These formulations are applied using low pressure treatment methods and have largely replaced ‘traditional’ light organic solvent preservative formulations. If timber treated at source by the boron diffusion process is available this may alternatively be specified. Sole plates, however are commonly treated with copper containing preservatives.
9. The housing warranty organisations have specific requirements for preservative treatment of timber components.