Sheathing can best be described as a protective covering or layer for your roof.
There are a number of different materials that may be used for sheathing purposes. Typically plywood is used because wood makes an excellent insulator and is very inexpensive.
Tongue and Groove is another type of commonly used sheathing.
Sheathing supports and protects the rafters. It’s the basis for the roof’s underlayment. It’s important that the sheathing remains in good condition.
if you see signs of sheathing decay, you will need to contact a local roofing contractor right away. You can visually inspect the sheathing yourself by looking in your attic. If you notice any dark or wet spots on the sheathing then you have a leak. Also, if you are checking the sheathing and notice that you can see pinholes of light through the roof they will need to be repaired.
Hiring a professional and experienced roofer to install the sheathing will ensure that the sheathing is properly spaced to provide ample support and prevent sagging. If there is a problem with the sheathing, the ventilation system and over all structure of the roof will be affected.