What the roof deck does
The deck, also called sheathing, is the flat wood surface that holds your roof. Shingles nail into it. Snow and wind load travel through it into the rafters. A weak deck cannot hold nails, so new shingles on a bad deck fail early.
Most newer homes use plywood or oriented strand board panels. Many older Grand Rapids homes have plank boards, sometimes spaced with gaps between them. Each type ages differently.
Why surprises happen
From the attic you can see some of the deck. From the yard you can see none of the top. Damage often hides under the shingles, around chimneys, along valleys, and at the eaves. That is why a good quote lists a price per sheet or per board for deck repair. It does not hide a single guess inside one number.
Published sources report deck repair at about $500 to $1,000 on a typical home, per HomeAdvisor. Large rot areas cost more. Our cost guide shows where deck work fits in the full price.
What crews find on the deck
| Finding | Common cause | What the crew does |
|---|---|---|
| Soft or rotted boards | Long-term leaks, poor airflow | Cut out and replace the section |
| Swollen or peeling panels | Moisture in the wood layers | Replace the panel |
| Gaps between planks | Old plank decking | Add sheathing over the planks, or fill and fasten |
| Popped or rusty nails | Wood movement, condensation | Remove, then re-fasten |
| Cracked or split boards | Age or past foot traffic | Fasten tightly, or replace |
| Dark stains or mold | Moisture from attic air | Replace, then fix the airflow |
How the repair works
- Strip the old roof. The crew removes shingles, underlayment, and old flashing down to bare wood.
- Walk and probe the deck. A trained roofer finds soft spots by feel and sound.
- Mark and photograph problems. You see what the crew found.
- Cut out bad sections. New wood goes in at the same thickness, nailed to the rafters.
- Dry-in the same day. Ice barrier and underlayment cover the deck before weather arrives.
Follow the full order on our installation process page.
Plank decking on older homes
Plank decking can work under new shingles if the boards are sound and tight. Gaps and uneven boards need attention. Many crews cover old planks with a layer of new sheathing. This gives the shingles a flat, solid base and costs more upfront. It saves trouble later.
The deck and your ventilation
Rot often points to a bigger cause. Poor airflow keeps the deck damp from below. If the crew finds dark staining along the whole deck, we check the attic. Replacing wood without fixing the cause invites the same damage again. Read our guide on attic ventilation.
How to avoid surprise costs
- Ask for a price per sheet or per board in writing.
- Ask how the crew will show you the damage.
- Ask what happens if the rot covers a large area.
- Set aside 10 to 15 percent of the budget as a cushion.
- Check the attic for stains before you sign.
Our guide on reading a roofing quote shows how to compare these lines between bids.
Code and the deck
Code sets a minimum panel thickness based on rafter spacing, and it requires proper fastening. Your inspector checks this on permit jobs. See our Michigan roofing code guide for more.
Plan your tear-off
A good crew protects your yard, shows you the deck, and keeps the house dry each night. Book a free inspection and we will explain what we see from the attic before any work begins.
Common questions
What does it cost to repair a roof deck?
Published sources put it at about $500 to $1,000 on a typical home. Large rot areas cost more. Ask for a price per sheet.
Will my roofer know about deck damage before tear-off?
Only some. The attic shows part of it. The rest stays hidden until the old roof comes off.
Can new shingles go over old plank decking?
Sometimes, if the planks are sound and tight. Many crews add a layer of new sheathing for a flat base.
How do I know the crew really replaced the wood?
Ask for photos of the problem areas and the new boards before the underlayment goes on.