Truss roof rafters - are they suitable for a house extension?

Many homeowners often assume that the roof design for their house extension will be using trusses or pre-formed trussed rafters. Many are shocked to be told that traditional timbers cut on site by a carpenter will be the preferred method of construction the new roof of the house extension.

This is mainly due to integrating and connection of the new roof structure with the existing roof and it is a lot more flexible to have a traditionally cut roof made to measure on site by an experienced carpenter than it is to try and make pre-formed trusses work when many of the pre-formed members will need to be cut and adapted to make it work on site anyway.

If the house extension roof was a ‘stand-alone’ type of roof design that was not connected or to be built onto the existing roof structure then trusses may be an option as it is these types of roofs where pre-formed trussed roof rafters come into their own.

The materials may be more extensive given the pre-formed design, manufacture and delivery to site but there is a saving in the erection time for the house extension roof when using trusses. However, even this may not be enough to have a cost saving as the real savings for using trussed roofs occur for multiple houses having similar roof designs when the economy of scale and production comes into play.