Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
Post and beam roof framing.
Whereas timber frame uses mortise and tenon joinery secured with wooden pegs.
However a modified post and beam can be built almost entirely out of cheap lightweight 2 x boards and the joinery is simply cleats and fasteners.
Above these components is a rack of common rafters.
In the same way you may need posts to support your roof beam.
Traditional timber framing requires very complex joinery and both timber framing and post and beam use heavy members that one can t hoist alone.
In the 37 years we have been crafting timberframes we have designed and built hundreds of timberframes and timber trusses for homes restaurants and wineries.
The beams of both techniques are fully exposed to the inside of the structure.
Choose a framing style based on your desire for more visible natural wood or one that allows brighter painted surfaces.
Post and beam construction has a very similar aesthetic and the joints can look similar but the stark difference is the connections are simple sometimes made with plates and bolts.
For those projects the connection is made by lag bolting the timber components together.
Some post and beam projects are done without the plates.
Post and beam typically uses half lap joinery with hidden fasteners and sometimes decorative metal braces.
A timber frame truss roof with ridge beam purlins and common rafters is a stunning combination that creates visual interest and structural complexity.
Roof framing system choose any combination of wall floor and roof systems to suit your style and fit your budget.
There is a hierarchy of timber framing at work here with trusses supporting the ridge and purlin beams.
If your span table shows the roof beam cannot support the roof rafters for the whole length of your house you will want to choose a built up roof beam whose maximum spans are the same as or slightly longer than your chosen floor beam spans.
Determining the ridge beam height.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Pacific post beam was founded in 1983 in sandpoint idaho as a custom builder of timber frame homes we relocated to san luis obispo in 1986.