Gambrel Roof Plywood Gussets

Gambrel roof a gambrel or barn style roof is simply a gable roof with a change in slope partway up the roof.

Gambrel roof plywood gussets.

With that said when designing gambrel roof it s very important to consider wind load and other load factors because of the odd angled shape and not having ceiling collar ties you have increased chance for rafter movement under wl ll and dl so the gussets must be sized correctly if not your roof. With your first truss measuring out ok its time to cut and attach gusset plates. Nail on gusset plates. Nailed plywood gusset roof trusses author.

If plywood is used the rule of thumb is 3 4 to match the thickness of the sandwiched rafter. For the gambrel truss we will need 6 total gusset plates made out of 1 2 material like osb or plywood. Check overhang to calculate rafter overhang equal to the lower level cut at the full rafter depth. Hardware is required at only three points as opposed to nine different joints in the roof assembly of a traditionally framed gambrel making the system considerably easier to build.

The gussets top in the gambrel system above designed by the author create a three hinged arch out of each frame which simplifies the load analysis significantly. Plywood gussets could then be used to reinforce the joint if necessary. Used a gambrel roof using plywood gussets used 3 4 so the two sides match the rafter thickness and did not cut them full triangles. Keep in mind that i used a ridge beam not a ridge board which substantially reduces the load and outward thrust issue.

Nail gusset plates to the truss at all 3 connection spots with 8d common nails using 10 per connection 5 per each truss end. Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape. Gambrel roof framing geometry calculator inch this gambrel roof fits in a semicircle and starts as the top half of an equal sided octagon.