Roof Rafter and Joist Replacement

The biggest enemy of any roof structures is water and rafters or joists are no exception. Water leaks can cause penetrating damp even in treated timbers. Even if your rafters and joists have been treated, the wood is unlikely to have been treated the entire way through its thickness. If your rafters sit on or in the walls, they will be even more susceptible to penetrating damp.

Another enemy of rafters and joists is rot or insect attack. These issues are typically associated with damp and can be problematic in older properties where no cavity walls or thick, solid walls support the bearing ends of your rafters. Rot and insects such as woodworm can cause the wood to start to crumble. The initial signs of woodworm are small holes on the surface of the wood, but eventually, the wood dries out, and the nutrients are drained, compromising the structural integrity of the rafter or joist.

Unfortunately, woodworm, or more precisely the adult beetles who spawn the woodworm larvae can migrate between May and October to find a fresh food source and new breeding ground.

Finally, your rafters and joists may be compromised by joint failure. Most modern roof structures use “nail plates,” which are plates fixed with screws, nails, and glue, but older timbers may be connected with wooden pegs or Mortise and Tenon joints, which can be eaten away by insects. This can allow the beams to move, which opens up the joint to further damage.