11 Best Of How To Support Sagging Rafters HD Image Size. Then use a jack raise the sagging joists and tie them to the strongback with the 2x4 blocks once they are in place. A day until theyre level.
The collar tie uses the opposing rafters to prevent sagging whereas purlins and knee walls use the bearing walls or ceiling joists below to resist rafter sag. Apr 10 2017 Once the rafter is back in its original position put one section of the iron piece over the top most section of the rafter. Keep the plywood in place using a piece of lumbar strapping until you can get a roofing expert to repair it.
Then use a jack raise the sagging joists and tie them to the strongback with the 2x4 blocks once they are in place.
Fix it on the place from where it is sagging or damaging. Nailing two 2x4s together will work to span about three joists unless the sag is under a weight-bearing wall. With the inverted hinged truss in place a vertical wedge can. How to Straighten Sagging Roof Rafters.