I m not a fan of spray foam.
2 layers of roof sheathing.
It s usually a peel and stick product that adheres directly to the roof deck.
Plywood used for roof decking is typically called sheathing and carries a grade stamp indicating its load and span ratings and other performance factors.
Assuming your roofing contractor is using standard 36 wide 15 roofing felt double coverage means that each layer of felt put down across the roof laps 19 over the upper half of the previous course.
Most roof decking is made from sheets of plywood.
Should you sandwich roof sheathing between two impermeable layers.
I am replacing a roof right now built in 1982 and the 3 ply is delaminated pretty heavily.
I think there are better ways to design an unvented roof for example by using rigid foam above the roof sheathing instead of closed cell spray foam on the underside of the roof sheathing.
Based on the pictures alone i don t know what to say.
It s up to you.
Roof deck is the roofing material that sits on top of the roof trusses.
Nailing new shingles over existing ones is less expensive and faster requiring less labor but it also means you lose the chance to assess the sheathing for signs of water damage.
Water shield is the next roofing layer that creates a water proof barrier where ice or water can buildup near the roof eaves.
Skinning over old sheathing does occur but i have never seen someone skin over plywood in that condition.
Dimensional comp shingles over 3 tab 1 1 4 1 1 2 1 1 2 1 1 2 more than 1 layer of roofing not recommended over 3 8 sheathing.
And if you re still wondering what roof sheathing is and what materials are typically used read on and satisfy your curiosity.
Poor ventilation from a past roof along with 3 ply equals that delamination.
Can you double up plywood roof sheathing without inviting disaster 2000 sf of 1 2 cdx ply went on the roof before i had a chance to take a look at it and it is really sorry stuff.
Roof sheathing materials plywood.
On a 2 12 pitch roof.
So anywhere along the gable end that you can see the felt you ll see two layers.
If you re in search of quotes for a roof sheathing job improvenet can put you in touch with up to four local contractors for free.
The first course starts with an extra 1 2 wide run.
Wood shakes minimum 3 4 sheathing wood shakes nail type minimum length.
Plywood is layers of wood.