A rafter is part of a roof, it supports the roof.
Typically, it is the part that extends beyond the building wall, aka tail of the rafter. It creates the area where you can stand under the edge of the roof when it rains.
The figures on the outer edge of the curve are degrees. Use these to set the angle/pitch of the roof. The figures on the inner edge of the curve are a ratio of the length of common rafter per foot or metre of run or span of roof. Take half the span of the roof in feet OR metres and multiply by the figure for the pitch of your roof this will give you the length of your rafter from birds mouth to the centre of the roof. Then make a deduction of half the thickness of the ridge board. at right angles to the bevel . The easiest way to use the bevels/angles from the square is to place the square on a piece of ply or board and mark all the bevels/angles onto the board and then use a sliding bevel/bevel square to apply the bevels/angles to the rafters and other members of the roof. No 1= Plumb & Seat cut for the Hip No 2=Plumb & Seatcut for Common Rafter No 3=Edge cut for the Hip (Mitre) No 4=Edge cut for Jack Rafter No 5=Side cut for Purlin No 4A=Edge cut for Purlin (Mitre) No 6 Lip cut to Purlin .This is the sloping cut which goes under the bottom edge of the Hip where the Purlin abutts to the Hip Rafter
use the 17" on your rafter square
Depends on what pitch the roof is. Measure the ceiling joist to a point or to center and then plumb to the rafter and do the math. 3, 4, 5, x 12 pitch rises that much per foot of distance on the ceiling joist. 3x12 pitch, 12 feet to center of joist, 3x12=36. 36 inch rise from the edge of the roof to the center.
A common synonym for "roof support" or "wooden beam" that is six letters long is "rafter."
They each have their place, but on the same style roof, trusses would be stronger.
Rafters are usually on 2 ft. centers.
The overhanging edge of a roof is called eaves.
The overhanging edge of a roof is called eaves.
eave The overhanging edge of a roof.
George. McEwin has written: 'Rafter lengths, roof bevels, and the steel square' -- subject(s): Roofs, Tables, Rafter gages