In order to build a roof for a large shed you needs the following.
Pitch break shed roof rafter framing.
A 9 pieces of 2 4 lumber 145 1 4 long cut at 60º at both ends bottom rafters.
Position the square at the end of the rafter board with the tongue on your left and facing away from you.
Corbett grace their parents and even their kids are learning a lot about the many ways a few right many wrong to build a high performance home.
For an 8 10 shed one sheet of plywood should be fine.
Blind valleys simplify framing.
2 4 rafters can span up to 7.
You are going to cut out triangles that will cover the apex of each set of rafters.
Drip edge and felt paper.
For heavy loads 2x4s can span up to 5.
Most roof framing is 24 on center and you can still build sheds up to 14 with 2 4 rafters at 24 on center.
Using a pitch measuring tool that i d made we also determined that the exact pitch of the shed roof was 3 1 2 in 12.
Position the square with both the 8 inch on the outside edge of the tongue and the 12 inch on the blade on the upper edge of the board.
Pitch break shed roof rafter calculator.
Board to length with the ends angled properly and then to mark and cut the birds mouth and seat on the rafter.
The roof rafters provide integral structural support to the roof.
Turn in a set of building blueprints with a pitch less than 3 12 or build a shed style roof with a low pitch and your building inspector will not pass the construction and provisions will have to be made to get the pitch up to acceptable standards if it is going to be shingled.
For light load roofs 24 o c.
This example is for a roof with an 8 12 pitch.
Using the law of sines c a sin c sin a c shed roof rafter length c1 90 shed roof pitch angle c2 90 main roof pitch angle shed roof pitch angle c 90 shed roof pitch angle 90 main roof pitch angle shed roof pitch angle c c1 c2 a main roof pitch angle shed roof pitch angle a shed roof run shed roof rafter length shed roof run sin 90 shed roof pitch angle 90 main roof pitch angle.
The roof on this shed is a 4 in 12 slope which makes it a 18 and one half degree angle on the board ends.
The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope.
Rafter layout with a framing square.
Spacing your 2 4 shed rafters at 24 on center limits the width of your roof.
The rule of thumb is that the gusset should be twice the width of the wood you use for your rafters.
So roughly 7 8 long for a 2 4.
A 18 pieces of 2 4 lumber 92 long both ends cut at 30º rafters.
A 18 pieces of 2 4 lumber 20 3 4 9 pieces of 2 4 lumber 38 1 2 long intermmediate rafters.