What is roof decking called?
Short answer. Roof decking is also called roof sheathing, the roof deck, or sometimes sheeting or substrate, and roofers often just name the material, as in OSB, plywood or boards. In insurance estimates it usually appears as sheathing, with the material and thickness listed, such as 7/16 inch OSB.
Names you will hear
- Sheathing. The term building codes and most estimates use. Wall sheathing is the same idea on the walls.
- Roof deck or decking. The everyday roofer's term.
- Sheeting or sheets. Field slang, as in "we replaced six sheets."
- Substrate. What manufacturers call whatever the roofing is fastened to.
- OSB or plywood. Often the material name stands in for the whole layer.
- Boards, planks or skip sheathing. Older solid sawn lumber decking; skip sheathing has wide gaps and was originally meant for wood shakes.
- Tongue and groove decking. Thick interlocking planks used where the underside is an exposed ceiling.
Why the vocabulary matters
When you compare quotes, one may say "replace damaged decking at a set price per sheet," another "sheathing as needed." They mean the same layer, but only one tells you the price. On an insurance estimate, sheathing replacement is its own line item measured in square feet, and it is often added later as a supplement once the deck is exposed during tear-off.
Not to be confused with
Underlayment is the sheet on top of the deck, and fascia and soffit are the trim boards at the roof edge. Read roof anatomy explained and OSB vs plywood roof decking.