How to Brace a Roof

Install 2-by-4 inch braces to the underside of the roof rafters. Mark off the two end trusses 8 feet up from the base of the roof then again every 8 feet after that. Place a length of 2-by-4 across the trusses so it sits at the mark on both ends. Use hammer and nails to fasten the braces in position on the trusses at the marked measurements.

Add blocking between the roof rafters. Take a measurement at each end of the roof about 12 inches or so from the outside end. Snap a chalk line across the two measurements and the entire length of the roof that falls in between them. Use a circular saw to cut pieces of blocking from lumber that is the same size as the rafters. For example, if your rafters are 2-by-8s, use 2-by-8s for blocking.

Place the first piece of blocking between the first and second rafters so it runs up against the left-hand edge of the chalk line. Use your hammer and nails to fasten the blocking in place. Drive two nails per blocking edge through the rafter and into the brace. Install the next piece of blocking against the right-hand edge. Repeat the alternating installation process between each of the remaining rafters.

Install cross-braces from each end gable to the fourth truss in the roof structure. Place a length of 2-by-4 lumber so that one end sits against the top of the vertical stud at the center point of the fourth roof truss and the other end sits against the bottom of the vertical stud at the center point of the end gable. Use your hammer and nails to fasten the cross-brace at both ends as well as nail it to the vertical studs of the first, second and third trusses against which it runs.

Mount the second brace component across the first so that it runs from the bottom of the fourth truss to the top of the end gable. Fasten it in place with your hammer and nails. Install steel roof ties at each attachment point for additional support. Position them around the brace and the truss member then use a wrench to fasten them in place. Repeat the process at the other end of the roof.