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What Kind of Timber Dimensions and Roof Pitch Would be Comfortable for a 36′ Span and Tennessee Location?

Asked by Dan on November 06, 2013

I really like your Modified King Post Truss. What kind of timber dimensions and roof pitch would be comfortable for a 36′ span and a  West Tennessee location and a SIP roof?

modified king post q&a

Answered by Doug Friant

Hi Dan,

I am glad you like the truss. We need some more information before we can size it though.

1) What is the spacing between trusses?

2) Are there purlins or rafters? (Purlins run horizontally, rafters run vertically)

3) What roof pitch would you like? A comfortable minimum for a 36’ truss would be around 5/12.

4) Do you have a layout of the roof so we can see if there are loads besides snow and wind that we need to consider? Such as other roofs above, hips, valleys, end walls or equipment?



  1. Don Elliott says:

    I live in Illinois and I also like the King Post Truss. I would like to know if you can build it with a 32′ span? 2′ overhang on each side with 28′ center for a total of 32′. The pitch can be anything, was considering a beam 8′ high in the center of the 32′ span. I thought about a truss, front and back with engineered or manufactured beams (lvl) joining the two with 26′ beams, if possible without any sagging.

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