Roof costs
Rotten roof decking replacement cost in Connecticut
Replacing a damaged 4×8 sheet of roof decking during a roof replacement costs about $135 per sheet, installed, with our current pricing. Every Thomas Roofing option already includes damaged sheets in the price (Essential 3, Core 5, Complete 8), and beyond that you pay the per-sheet price written in your contract, with photos first.
Updated September 16, 2026
What roof decking is
Roof decking, also called sheathing, is the layer of plywood or OSB sheets under the shingles that everything else is nailed to. When water gets past worn shingles or flashing, the decking can soften, delaminate or rot, and new shingles can’t be fastened properly to it.
Signs your decking may be damaged
- Soft or spongy spots when someone walks the roof
- A roofline or roof plane that sags between rafters
- Water stains, dark patches or daylight on the underside of the roof in the attic
- Shingles that won’t lie flat, or nails that have backed out
What it costs
| Damaged sheets beyond what your option includes | Added to your price |
|---|---|
| 1 sheet | about $135 |
| 5 sheets | about $670 |
| 10 sheets | about $1,335 |
| 20 sheets | about $2,675 |
Priced on a two-story colonial with our Core option. Computed by our pricing engine on 2026-09-14 from pricing table v1. Ranges assume one existing layer of shingles and a standard install week.
How many sheets each option already includes
| Option | Damaged decking sheets included |
|---|---|
| Essential | 3 |
| Core | 5 |
| Complete | 8 |
How decking is checked and priced
- Before you sign, a technician checks the decking from the attic side or with a small test cut, and photographs what they find.
- You see your final price, including any decking beyond your option’s allowance, before you sign and before any work begins.
- If more damaged decking turns up once the old roof is off, you see photos first, and each sheet is billed at the price already written in your contract.
- Sound decking stays. Only damaged sheets are replaced.
Questions
- How much does it cost to replace rotten roof decking in Connecticut?
- About $135 per 4×8 sheet, installed, during a roof replacement with our current pricing. Each Thomas Roofing option already includes some damaged sheets in the price.
- Can you tell if decking is rotten before the old roof comes off?
- Often, yes: from the attic side, from soft spots on the roof, or with a small test cut at the verification visit. Some damage only shows once the shingles are off, which is why your contract already states the per-sheet price.
- Will you replace decking that is still good?
- No. Only damaged sheets are replaced, and you see photos of them.
See a price range for your own roof
About 10 minutes, from aerial measurement. No salesperson.