The thermal performance of timber frame walls is very poor compared with other traditional construction and will struggle to meet modern expectations. Improvements to the insulation of timber-framed buildings can help reduce fuel bills and carbon emissions but these are not without risk and care must be taken to ensure that any improvements don’t compromise the structural integrity of the building.

There are a range of insulating timber frame walls methods and materials that can be used to insulate timber frame walls. The most common is to use a sheathing of 2 x 6 tongue & groove, V-jointed pine planking which is fastened vertically across the studs in the wall and provides a nailing base for the timber frame and plasterboard lining. This method allows a service channel to be run through the internal wall lining which is useful for electrics and plumbing.

“Insulating Timber Frame Walls: Key Considerations and Methods

Rigid foam insulation sheets can be used to insulate timber-frame walls with impressive U-values achievable using this approach. Typically this is PIR (polyisocyanurate) foam, although Kingspan and other manufacturers have also developed products using XPS (extruded polystyrene).

Where the existing infill panel is of unsuitable material or has been removed to facilitate structural repairs to the timber frame there may be an opportunity to re-insulate the wall with a lightweight prefabricated Structural Insulated Panel (SIP) that can be quickly installed on site. This can provide good u-values with lower rates of thermal bridging than stick framed walling and, where cladding is reinstated to the original/existing finish, need not have any impact on the visual appearance of the building.

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