How to fix the rafter

To fix the rafter, you are basically just cutting out another rafter to put right next to it, otherwise noted as the "sister" rafter. Cut your plywood to match the length of the existing rafter. If part of the old rafter is split in half, try to remove it and then accommodate for the length subtracted with the new wood. Use a tape measure for measurements and a pencil to mark where to cut. Then use a table saw to finish the job.