Roof Sheathing Over Old

Walking on the roof feels very spongy.

Roof sheathing over old.

The anchor of the system that keeps. The roof is sheathed with either 3 8 or 7 16 inch plywood. I have it under contract to resheath and reroof. 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.

Sheathing works with other components of the roof as well. Two questions about replacement of roof sheathing. Question 1 which is preferable from a quality perspective cost is secondary. 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.

Housing and urban development hud rehab guide. 50 year old house with 3 8 plywood sheathing on trusses spaced at 24. It is now warped and wavy. 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. But can he simply install new plywood over the old. Today a shiplap roof is usually 60 years old. Because the plywood roof sheathing under the shingles has become brittle and weak he plans to install new plywood as well as new shingles.

This guide was developed and edited for old homes from original material in the u s. As roofing contractors in seattle we are often asked why do we need plywood over our old solid sheathing. Over time shiplap fir wood resin dissipates causing the boards to shrink crack form knot holes and become extremely brittle. There does not appear to be any roof leaks but from poking at the sheathing from below there appears to be dry rot.

Roof sheathing provides an area where the surface material can be attached but it also helps keep the trusses and or rafters properly spaced. Roof shingles are to be replaced.