Roof Joist Framing Construction Details

Intermediate bearing with blocking panels.

Roof joist framing construction details.

Good installation begins with specification of the correct joist for the application. In a rafter roof all of these components are required to provide a stable roof. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. In addition to floor and roof framing details this guide includes recommendations for cantilevers and placement of web holes.

Here we have a wood framed gable roof. The construction of the flat roof is similar to that of the timber upper floor. The function of each component is. I joists in floor and roof applications.

I joist construction details. End bearing in hanger on a top plate. Let s consider a basic gable wood roof framing design. End bearing in hanger supported by i joist s 44kb.

Continuing on from part 3. Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Meeting current irc roof framing requirements means builders are really constructing very simple triangles using the rafters and ceiling joists because triangles are known to be the most stable shape. End bearing in hanger supported by a beam.

End bearing with rim joist. Not shown are the hip and valley rafters needed to tie the roof together where the rafters are framed at an angle to each other. In order to maintain the triangle shape there are specific requirements for how to fasten the corners of the triangle together. End bearing with rim board.

Prescriptive roof consisting of the rafters a ridge board ceiling joists and collar ties.