Roof Decking: What Happens When Rot Is Found at Tear-Off

Roof decking is the layer of wood, usually plywood or OSB, that sits on the rafters under your shingles and underlayment. Everything on your roof is nailed into it. If the decking is soft or rotted, new shingles cannot hold, and the new roof will not last.

Why decking rots

• Old leaks: a slow leak at a pipe boot or flashing can soak the wood for years before it shows inside.
• Poor attic ventilation: trapped heat and moisture condense on the underside of the deck.
• Missing drip edge: water runs back under the shingles at the roof edge.
• Several layers of old shingles: older roofs with two, three or four layers often hide rotted decking underneath.

Signs of bad decking

• A roof that looks wavy or sags between rafters.
• Soft or spongy spots when walked on.
• Dark, stained or moldy wood seen from the attic.
• Daylight through the roof boards in the attic.

How we handle decking on a replacement

We tear off down to the deck, so we see the wood before anything new goes on. If rotted decking turns up, it is photographed, priced in writing and approved by you before it is replaced. No surprise line on the final bill.

We do not lay new shingles over old ones. Our roof replacement page explains why, and our roof prices page shows our published ranges.

Frequently asked questions

Will insurance pay for rotted decking?

It depends on your policy and your carrier, and on whether the rot came from a covered event. Our pricing page explains how we handle it; confirm coverage with your agent. This is general information, not insurance advice.

Can decking be replaced in just one section?

Yes. Only the damaged sheets are replaced, and you see each one before it is done.

Is roof decking the same as roof sheathing?

Yes. Roof decking and roof sheathing are two names for the same thing: the boards, usually plywood or OSB, that the underlayment and shingles are fastened to.

Planning a new roof?

Our replacement inspection is free and includes an attic check. Book your free storm or replacement inspection.