Roof Sheathing Over Old

But can he simply install new plywood over the old.

Roof sheathing over old.

The roof is sheathed with either 3 8 or 7 16 inch plywood. Sheathing is installed over multiple trusses rafters so it essentially turns them into one cohesive unit instead of individual structural members. Roof sheathing the material nailed to your trusses or rafters to which your roofing is attached is your roof s workhorse. The anchor of the system that keeps.

Roof shingles are to be replaced. Roof sheathing provides an area where the surface material can be attached but it also helps keep the trusses and or rafters properly spaced. Attic ventilation comprises of a poorly installed ridge vent with no soffit vents. This guide was developed and edited for old homes from original material in the u s.

Over time shiplap fir wood resin dissipates causing the boards to shrink crack form knot holes and become extremely brittle. Housing and urban development hud rehab guide. Apply new roof sheathing osb directly over old sheathing sagging inch plywood or rip the old sheathing off and apply new sheathing to the trusses. 50 year old house with 3 8 plywood sheathing on trusses spaced at 24.

The keyword here is solid it used to be standard to use shiplap 1 boards tongue groove or other boards for the roof deck. It is in your best interest to apply solid sheathing over the existing shiplap for your roofing system to securely fasten to. Sheathing works with other components of the roof as well. Two questions about replacement of roof sheathing.

As roofing contractors in seattle we are often asked why do we need plywood over our old solid sheathing. Today a shiplap roof is usually 60 years old. There does not appear to be any roof leaks but from poking at the sheathing from below there appears to be dry rot. Walking on the roof feels very spongy.

It is now warped and wavy. The contractor has asked if it is possible to leave the old sheathing in place and install the new 5 8 inch sheathing over the top of it.