2 Layers Of Plywood On Roof

3 8 plywood roof sheathing.

2 layers of plywood on roof.

Both osb and plywood for the roof have been approved for use so it. And plywood or osb roof decking thus ultimately into the attic space. I urge you to remove both layers of roofing so that the new roof investment will last as long as its intended to and that you have peace of mind that your roof is sound from top to bottom inside and out. On a 2 12 pitch roof.

The alternating grain gives the plywood a system of checks and balances that allow it to expand and contract evenly across the sheet. It is typically made in 4 by 8 foot sheets although longer panels are available for special purposes. On roof slopes of 2 12 to 4 12 the remainder of the roof shall be two layers of 15 felt applied in shingle fashion or 1 layer of ice dam protection. The roof deck turned out to be 3 8 plywood which is starting to break down due to the number of times the roof has been replaced.

The attic was well vented with gable vents so i dont think it is a heat issue. 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. Plywood is made with three or more layers of thin wood glued together with the grain alternating. Can you double up plywood roof sheathing without inviting disaster.

Also was the plywood in 1960 defective. Every house in the neighborhood is being redone and havent seen any other 40 contractors in the neighborhood doing all the plywood installation. The deck is not rotting out except for a few spots along the drip edge which we are cutting out to replace. 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.

But unlike an asphalt shingle roof. Most building codes allow for two layers of asphalt shingles on a house so stripping off everything down to the plywood sheathing may not be your only choice. Even though 2 roof layers are legal we do not like covering over any old roofing materials with another layer because we don t believe in covering up problems. This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer.

The main issues are that you can hear the plywood cracking and feel it give under you as you walk around. It got nailed over 2 x 12 joists 24 o c.