2 Layers Of Plywood On 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.

2 layers of plywood on roof.

3 8 plywood roof sheathing. And plywood or osb roof decking thus ultimately into the attic space. 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. This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer.

Plywood is made with three or more layers of thin wood glued together with the grain alternating. But unlike an asphalt shingle roof. The alternating grain gives the plywood a system of checks and balances that allow it to expand and contract evenly across the sheet. Also was the plywood in 1960 defective.

On a 2 12 pitch roof. The roof in question is my neighbors roof i just had seen the contractor putting the second layer of plywood on over the tarpaper and thought it was kind of strange so i thought i would ask. 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. Can you double up plywood roof sheathing without inviting disaster.

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. On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt. Wood structural panel sheathing or siding used to resist combined shear uplift. It got nailed over 2 x 12 joists 24 o c.

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 deck is not rotting out except for a few spots along the drip edge which we are cutting out to replace. 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. Both osb and plywood for the roof have been approved for use so it.

The attic was well vented with gable vents so i dont think it is a heat issue. It is typically made in 4 by 8 foot sheets although longer panels are available for special purposes.