Roof Ledger Board Size

Lag screws may be spaced at 16.

Roof ledger board size.

As a rule of thumb bolts can be spaced 16 on center for supporting joist span up to 12 in length. This tells you the size of the beam needed to support the porch s roof. Calculate the initial value for d then round it up to the nearest inch. Douglas fir lvl no attachment is allowed to strand lumber syp lvl the mudsill i joists floor trusses or other materials.

2x6 p treated bolted as the size of your deck. This means the example porch would need a 6 inch by 8 inch beam. The closer the rafters are to each other the stronger the roof will be. It is always better to have a large rafter rather than be concerned with a sagging roof.

House rim joist must be minimum of 2x sawn lumber or 1 in. You want a flashing that won t react with. It should be 6 8 inches above grade ideally but you can get ground contact pt that can be placed closer. Ledger the same size as the rafters and fastened to the studs with x5 lag screws spaced page 2 of 6 at 32 maximum on center for up to a 10 0 rafter span.

In the example d calculates to 7 75. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. X 9 in. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

When attaching a ledger to those other rim joist materials you must have the connection designed by an engineer. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.