Pictured at left is a 2x6 rafter spliced together using 3 4 plywood.
Splice roof rafters.
Measure rafter spacings of 24 inches with a tape measure and plan the splice to fall between rafters.
When you prepare to make the splice note the rafters location.
Rafter splicing is typically used as a last resort for erecting rafters and is not generally the preferred method of constructing roofs.
Several have a plywood scab brace on the side but several do not.
The roof rafters are 2x8 on 16 centers with 2x10 ridges.
Rafter splice forgive the crude drawing will post pic but it is hard to see.
A 30 foot roof for instance will need at least two boards.
A splice should end between rafters not where a rafter lands directly on the splice.
Rafter plates are almost always spliced due to the length of most structures.
A ridge board is a much better way to secure rafters to your roof and will almost always be a better way to go.
Some roofs are much longer than average milled board lengths which creates the need to splice one ridge board to the end of another ridge board.
How to splice a roof rafter plate.
In this case the rafter as a whole is actually stronger than it would have been because the splice is more than adequate and the plywood adds to the strength.
Rafter plates are load bearing beams that support either a single rafter or a truss.
In this case the framer just needed a longer rafter.