2 Layers Of Plywood On Roof

The attic was well vented with gable vents so i dont think it is a heat issue.

2 layers of plywood on roof. 3 8 plywood roof sheathing. 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. Both osb and plywood for the roof have been approved for use so it.

The alternating grain gives the plywood a system of checks and balances that allow it to expand and contract evenly across the sheet. Roof deck is the roofing material that sits on top of the roof trusses. 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. However 3 4 th inch plywood is also used for a roofing system that has a heavier load.

The main issues are that you can hear the plywood cracking and feel it give under you as you walk around. For many years it was acceptable to put even the third layer. Snowfall and ice accumulation can affect the load put on a roof. 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.

It is typically made in 4 by 8 foot sheets although longer panels are available for special purposes. Most roof decking is made from sheets of plywood. Steep sloped roof products such as tile slate metal and shakes only allow one layer. Wood structural panel sheathing or siding used to resist combined shear uplift.

For the less standard 20 inch apart rafters plywood with inch or 5 8 th inch thickness can be used. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. Plywood is made with three or more layers of thin wood glued together with the grain alternating. Also was the plywood in 1960 defective.

This particular type of plywood is crafted from layers of wood stacked on top of one another with alternating grain patterns in each layer.