how to make a birds mouth on rafters

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When I cut rafters, I don’t have to follow certain design specifications, like cutting the rafter tails to meet the top of a window with a specific size fascia, etc. I’ll cut the birds mouth seat to fit the plate’s width—in your case, 3 1/2″. This will enable a sufficiently wide space for nailing on both sides. The consideration would be what is the narrowest width of the rafter will be at the birds mouth and how wide the overhang will be, and will that narrow dimension support the overhang you are considering? It could be smaller; I believe the code allows down to 1 1/2″ with collar ties/ceiling joists (needs verification). Whether you plan to add “lookouts,” or blocking that is added under the overhang to create a level soffit, will also have an impact on this decision.

Answer 1: There are several ways to accomplish this; the drawing you did is just one of them.

Answer 2: The corner created by the bird’s mouth cut in what you have drawn will be unsupported beyond the gable wall. Everything that isn’t supported basically makes your material smaller because it can split and isn’t supported. Your drawing of the 5 1/2″ dimension does not accurately depict the material’s strength. If I put it correctly, the strength runs the length rather than at an angle with regard to how the rafter lays. My apologies if it leads to some confusion.

Answer 3: I think there is room for some wood to extend past the plate’s inside edge; if this is the case, a metal strap may be necessary or desirable to prevent the rafter from splitting along the unsupported edge. Although a ceiling rafter would be beneficial, since you are building a cathedral, that is not an option. Instead, ceiling rafters Without the need for nailers, finishing can easily follow the line created by setting the cut for the bird’s mouth edge at the plate line.

Answer 4) Nope I dont think so.

Answer 5) Maybe, I do the same thing.

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Why is the Birdsmouth Essential?The design of the birdsmouth ensures that the weight of the roof is evenly distributed over the walls. This even distribution prevents undue stress on any single point of the roof structure, ensuring longevity.

  • Toenails: These are hammered straight into the wall plate through the birdsmouth.
  • Metal Rafter Tie Down Plates: These plates provide an extra degree of security for individuals seeking it.


How deep should a birds mouth be on a rafter?

the depth should be one third the width of the rafter , most cut the depth to 1.5″ or two inches on a two by four , the length from the top of the cut to the edge of the rafter is the width of the rafter or 3.5″ .. Not for a 2×6 wall. It also depends on the width of the rafter and the desired width of the tail.

What can you use instead of birdmouth on rafters?

Alternatives to making birdsmouth cuts in rafter framing include using metal brackets, adjustable angle connectors, or custom-cut gussets to achieve similar structural integrity. Each alternative has its pros and cons depending on the specific requirements of the project.