Roof Sheathing Over Old

Roof sheathing the material nailed to your trusses or rafters to which your roofing is attached is your roof s workhorse.

Roof sheathing over old.

Two questions about replacement of roof sheathing. Today a shiplap roof is usually 60 years old. Roof shingles are to be replaced. Sheathing is installed over multiple trusses rafters so it essentially turns them into one cohesive unit instead of individual structural members.

The roof is sheathed with either 3 8 or 7 16 inch plywood. The anchor of the system that keeps. Over time shiplap fir wood resin dissipates causing the boards to shrink crack form knot holes and become extremely brittle. It is in your best interest to apply solid sheathing over the existing shiplap for your roofing system to securely fasten to.

Attic ventilation comprises of a poorly installed ridge vent with no soffit vents. Roof sheathing provides an area where the surface material can be attached but it also helps keep the trusses and or rafters properly spaced. I have it under contract to resheath and reroof. As roofing contractors in seattle we are often asked why do we need plywood over our old solid sheathing.

Because the plywood roof sheathing under the shingles has become brittle and weak he plans to install new plywood as well as new shingles. 50 year old house with 3 8 plywood sheathing on trusses spaced at 24. Walking on the roof feels very spongy. There does not appear to be any roof leaks but from poking at the sheathing from below there appears to be dry rot.

This guide was developed and edited for old homes from original material in the u s. 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. But can he simply install new plywood over the old.

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. Question 1 which is preferable from a quality perspective cost is secondary.