Timber Frame Explained
An increasingly popular build route, timber frame is the method of choice for offsite construction and is often used as the structure upon which to layer other ecobuild materials such as straw bale, hempcrete (lime and hemp mix), and rammed earth.
Most common are layering with boards, often OSB, and specifying high levels of insulation and airtightness. With a platform frame, the floors are built in boxed sections while a balloon frame has a continuous wall structure from ground floor to eaves level which means it can’t go much higher than two stories because there is no timber long enough to reach further in one go.
Balloon frames are quicker to erect to a watertight stage. Prefabricated systems are either open or closed panel (fully finished wall): open is the most popular because it is easy to put together but it requires the fitting of services and insulation on site.
Closed panels are made in their entirety in a factory, including insulation, wiring and window and door linings; once in place the walls don’t need to be drilled or cut, just decorated. As long as there is no damage this method ensures a high spec finish.
The timber is usually graded softwood but you can go with stunning oak and keep them exposed inside, or full logs to give a chalet look. Log construction at its most basic consist of piling them up to form walls with dovetailed joints chopped out at the corners to interlock.
Post and beam is not as commonly used in Ireland and when imported from the USA often consists of structural softwood such as spruce or fir. Even though you can clad a timber frame house with anything you wish, in Ireland people often build a row of blockwork on the outside for weatherproofing, and to ensure the house blends in with neighbouring buildings. Not to be confused with SIPS which are assembled insulated timber panels (there is no timber frame).
What are the benefits?
Achieving a high spec in terms of insulation and airtightness is relatively straightforward, cost efficient and quick as there is no drying out period to factor in. However you should take into account the amount of time it will take to build the structure offsite to your specifications.
‘Even though you can clad a timber frame house with anything you wish, in Ireland people often build a row of blockwork on the outside for weatherproofing, and to ensure the house blends in with neighbouring buildings.’
As long as sustainably sourced wood is used, timber frame has eco-credentials. The raw material is renewable and the wood locks in carbon dioxide. Also the manufacturing process is less energy and carbon intensive than many of the alternatives (concrete or steel) and leads to considerably less waste as most by-products are reused.