I Joist Used As Roof Rafters

I joists are used extensively in residential floor and roof framing.

I joist used as roof rafters.

They are ideal for long spans including continuous spans over intermediate supports. Should not be cut like near the b vent. Syp 2 6 rafters at 24 o c. It is always better to have a large rafter rather than be concerned with a sagging roof.

Insulation should be 1 inch from b vent. Software weyerhaeuser offers an array of software packages to help you specify individual framing members create cut lists manage inventories even to help you design a complete structural frame. 6 8 sloped bearing conditions. Just found this interesting.

Looks like they can be used as rafters. With an 8 soffit your rafter without a ridge deduction is roughly 20 4 3 4. All you need is 22 2x10 s or 2x12 s. Because i joists are straight and true it s easier for builders to avoid crowning and maintain a level framing surface.

There s no reason to used i joist with a 15 span. No solid sawn conventional lumber should be used as rim joist with i joist. Bci joists are specially constructed i joists with flanges made from strong versa lam laminated veneer lumber with oriented stranded board webs and approved waterproof structural adhesives providing outstanding strength and durability. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.

If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. Trus joist tji s31 s33 and s47 joists for use in eastern canada. Again put them closer together if you want to achieve a greater span. 2 0 maximum cantilever roof truss span 2 0 maximum cantilever hip girder trusses truss roof trusses 13 0 maximum roof truss span.

Photo 2 shows a view of the other ends of these same i joist rafters and the use of. Can span over 18 for gable roofed shed. These i joist rafters are on 24 inch 61 cm centers and support plywood roof sheathing and wood shingles. Use 2 6 rafters if your roof will experience heavy snow or wind loads.

When wood i joists are used as rafters connections at the structural ridge and the tops of exterior walls must be detailed properly. Pdf says to consult with specific manufacturer for design installation specs. An spf rafter can span nearly 15 at the same dimensions.