Old Roof Decking

Plywooding over old roof deck one thing to consider when stripping off the old plywood is to remove and replace as you go.

Old roof decking.

Prevent future mold growth. If there is a leak in the roof plumbing or windows the mold will reappear if the water is. Roof decks on homes built before 1970 are often 1 8 fir pre plywood shiplap. Until the 1940s exterior grade plywood was not available.

Since the boards used for shiplap were manufactured here in the pacific northwest it was still cheaper than plywood up through the 1960s. We knew that this old house had significant gaps in the wood p. Older homes may very well have a different type of roof decking than newer structures. Old houses with asphalt shingles usually had either tongue and groove boards or straight sided boards abutting.

It is important for us to point this out because here in maine many historic homes are maintained for both residential and business uses. In older houses decking is typically made of lumber place perpendicular to rafters trusses. That will save you as much as 1 000 and a fair bit of mess but it means the roofer can t inspect and repair the decking and flashing underneath. Plank sheathing usually 1 6 or 1 8 was used as a roof deck before plywood.

It s important to know what kind of a substrate is underneath the wood shakes before removing. As long as the new plywood itself can span the distance and carry the roof wind seismic and snow loads for your region adding new ply over old is just fine. If you remove it all then reinstall you can have cracking and popping of the drywall ceiling. The new plywood thickness should be.

To prevent future mold growth remove the source of moisture causing it. In the 1950s plywood sheathing and particleboard became common and today most standard construction roofs use either half inch plywood or particleboard s big brother oriented strand board osb.