Low Energy House - Timber Frame Housing - Off Site Building

In contrast to masonry construction, the timber frame housing results in relatively low thermal capacity and consequently the building envelope can heat up very quickly. In a house, where heating is intermittent, this fast response can result in increased comfort and energy saving

Timber Frame Housing - Carbon Neutral Timber

Timber is a natural material and requires minimal energy to process it into construction materials. During its growth, timber absorbs carbon dioxide and stores the carbon in its cellular fibres. When it is finally burnt or rots away it releases an equal amount of carbon to the carbon it has already absorbed, making it carbon neutral.

Advantages of Timber Frame Housing

Timber frame house construction has advantages over masonry construction because it allows a greater thickness of insulation to be used in the external walls.

A cavity is not always necessary in timber frame house construction as long as an appropriate vapour control layer is incorporated on the warm side (in winter) of the insulation. Timber frame house construction can achieve U-values significantly higher than the minimums required by current Building Regulations.

Timber Frame Housing Construction

In timber frame housing, the floor and roof framing are similar to those in conventional forms of construction, only the junction detailing is different.

Timber Frame Housing - Insulated Timber Panels

Timber frame housing is manufactured as panels, under factory conditions, and then transported to the site where the panels are assembled. The panels are constructed of timber studding and a plywood (or similar board) material, known as sheathing, and are nailed onto the exterior of the timber frame to form the rigid panel.

Strength graded timber must always be used and 89mm x 38mm and 140mm x 38mm are the most commonly used timber section sizes.The sheathing provides the necessary panel stiffness to resist lateral forces due to wind loads. The internal lining material can also contribute to wind resistance. The size of the panel can vary, with larger panels requiring crane handling.

Timber Frame Housing - High Standard of Workmanship

In timber frame housing, a factory controlled environment will produce a consistently high standard of workmanship. Prefabrication and the absence of wet trades internally means less site time will be required.

Timber Frame Housing - Typical Construction

A typical timber panel external wall will comprise a 100mm deep timber frame stud filled with 100mm insulation, a 50mm air filled cavity and a 100mm facing brick outer leaf. This results in a 250mm thick wall which is thinner than a conventional masonry wall but has greatly improved thermal performance. The thermal performance of the external wall can easily be improved by using a 150mm wide timber stud instead of a 100mm stud to form a 300mm thick wall.

Timber Frame Housing - External Wall Finishes

Timber frame walls can be faced with load bearing brickwork or cement rendered blockwork. Lightweight cladding materials that can be fixed to the timber frame include tiling, slating, timber boarding, cedar shingles, cement render on lathing and proprietary rain screens.

Timber Frame Housing and the Building Regulations

The Building Regulations require external walls to have thermal performance levels by way of insulation and airtightness. Durability of the insulated timber frame is an essential requirement as walls need to provide support for the cladding materials. External walls are also required to have appropriate fire resistance and internal spread of flame characteristics.

Housing Warranty and Guarantee Authorities have specific requirements for aspects such as sheathing materials, breather membranes and the preservative treatment of external wall framing