Timber framing is typically designed and supplied by a Timber Framing Contractor or Frame and Truss company to the Australian Standard AS1684 Residential Timber Framed Construction. This is particularly the case with new house construction. In some smaller projects such as upper floor additions and ground floor additions the timber framing is cut on site by a carpenter. In some cases, the carpenter will design and size all of the timber themselves and in some cases they want to get an Engineer to provide input, sometimes for all of the design, sometimes for just some elements.
When a timber framing contractor is involved, they will design the vast majority of the timber frame including wall frames, floor joists, bearers, roof trusses, bracing and tie down details. They have the ability to do this with specialist software. It’s an efficient way to do it because they make their margin on the supply of the timber. They will however require the engineers input for the upper level floor frame if there are to be steel beams, as they are not usually qualified to design steel beams or timber beams with unusual loading, large spans and cantilevers. Many designs of two storey residences have tricky geometry with external brick walls that don’t line up with brick walls below, these will require an upper level floor frame plan with steel beam and post details. Depending on how many beams need to be designed, we will typically do a raft slab, footings and upper level floor frame design for $950 + GST.
We are also very experienced at designing floor frames and bracing for upper floor additions on existing houses. We also do inspections to check whether the house is structurally adequate to withstand the loads of the proposed addition and provide a letter certifying the adequacy of the existing residence as required by council.