How to Fix Split Roof Rafters

Jack the rafter up into its original position if it's sagging. Do this by placing a jack post on the floor beneath the rafter, placing the top of the jack post against the bottom face of the rafter and turning the screw on the jack post to force it upward. If the rafters on each side of the split rafter are in good condition, it shouldn't be too hard to push it upward.

Spread construction adhesive on two pieces of 2-by-6 lumber that are at least 3 feet long.

Place one 2-by-6 on each side of the split rafter so that the rafter is sandwiched by the two 2-by-6s, the construction adhesive is pressed against the sides of the rafters and the split is centered along the length of the two pieces. Clamp the two pieces in this position using a clamp at each end.

Drive 4-inch-long screws into the 2-by-6s so that each screw goes through one 2-by-6, through the rafter and into the other 2-by-6. Do this in both directions, driving screws through the faces of both 2-by-6s. The more screws you use, the stronger your repair will be.

Remove the clamps and the jack post.