Timber structures Timber frame
Insulation/vapour control layer
Party floors, ceilings and walls
The location and type of insulation must be suitable for use with timber frame, and any gaps or uninsulated areas can reduce the thermal performance of the building envelope. Insulation will be specific to each project and must be carried out according to manufacturers’ guidance.
The acoustic performance of party walls and floors depends on both specification and workmanship, and separation of party wall leafs and floating floor perimeters are paramount. Particular care should be taken at wall/floor junctions, as air paths reduce acoustic performance and can compromise fire resistance.
The durability of a structure is ensured by keeping the timber dry. In most timber frame walls, this is achieved through a combination of a vented cavity between the frame and the external cladding and a protective breather membrane on the ‘cold’ side of the insulation. The vapour control layer prevents interstitial condensation forming within the wall structure and also significantly contributes to airtightness.
Dry lining Plasterboard wall linings help to provide fire resistance and acoustic performance, so correct specification and fitting is critical. Fitting should not occur until the frame is watertight and the timber has been checked to ensure it contains less than 20% moisture. Plasterboard should not be installed Image 62 - Junction of party wall before services in walls have been tested.
Air movement in party wall cavities can lead to significant heat loss and result in what is known as party wall thermal bypass.
Damp‐proof courses Damp‐proof courses (DPC) prevent moisture transmission by separating timber from materials that could transfer moisture to it. DPC cavity trays should be lapped to deflect moisture away from the timber, and windows and doors should be sealed to the timber frame via a DPC to help maintain a weathertight seal. >>
Seal
Cavity barrier if required
Batten to support ceiling
Party wall strap if specified (diagrammatic location) Junction of party wall
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Timber 2019 Industry Yearbook
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