Roof Pitch Birdsmouth Cut 2x6

But for a 2x12 rafter on a roof with a steeper 12 12 pitch the seat cut can be no longer than 4 inches before the d 4 limitation is exceeded.

Roof pitch birdsmouth cut 2x6.

How to use a framing square to lay out the birds mouth cut on a rafter. If the rafter is cut for full bearing on a 2x6 wall the resulting notch would be deeper than 2 13 16 inches. Height above plate table 3 12. All roof rafters should be identical so follow the same steps to measure the plumb cut tail cut and birdsmouth cut.

Before we start marking or cutting anything you have to be aware of that fact that your birdsmouth should be no more than a 1 3 one third the total depth of the timber you are using. This article series explains how to use a framing square and in companion articles we give examples just about every possible way to figure out any or all roof stair or other building framing dimensions and measurements including problems such as figuring the roof area width length and roof or stairway slope rise. It can be difficult to visualize rafter plumb and side cut angles and how the common hip and creeper rafters all fit together. The actual indentation or cut is known as the birdsmouth while the birdsmouth plumb is the depth of the cut out.

Here the birdsmouth plumb is 76 37 inches. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. For example if you are using 6 x 2 timbers the birdsmouth should be no greater than 2 inches deep. At this point you ve cut 1 roof rafter.

How many of us are under the 1 4 of depth or some other fraction rule by code and inspection when cutting birdsmouths in rafters. The number of rafters needed will be determined by the length of your roof. I have attached a sketch that shows how for a 2 12 rafter with full wall notch over 2 6 wallframe and 1 2 sheathing if wanting the springline from the inside edge the max pitch for the roof is 6 3 8 in 12. Birdsmouth plumb if you study the diagram carefully you will see that there is an indentation in the roof rafter where it meets the exterior wall of the building.

Depending on the size of your structure you will need to cut several or many more. Rafter seat cut length each rows shows seat cut length with h a p for material size.