Residential roofing
Roof decking and resheeting
Roof decking is the layer of plywood or boards the roof is fastened to. When it is soft, rotted or delaminated, a new roof on top of it will not last.
Why the roof deck matters
Every nail in a new roof holds into the decking. If the wood is soft or rotted, fasteners do not hold, the roof can sag between rafters, and leaks follow.
Decking fails mostly from water: a slow leak that went unnoticed, condensation from poor attic ventilation, or moisture held against the wood under several old layers of roofing.
Signs you might notice ahead of time:
- A roof that feels spongy to walk on
- Sagging between rafters
- Dark, stained wood when you look up from the attic
Replacing sections or resheeting the whole roof
If the damage is limited, the bad sections are cut out and replaced. If it is widespread, or the existing boards are not suitable for the new roof, the whole roof gets new sheathing. Either way it happens during the tear-off, before the underlayment goes down. See roof replacement for the rest of the job.
The Ogden three-layer tear-off
On one Ogden job, the roof had three layers of old roofing on it. When all three came off, the decking underneath was bad. With that many layers on top, nobody could have seen it beforehand. The full story is on the projects page.
Questions homeowners ask
Can bad decking be spotted before the roof comes off?
Sometimes, from soft spots, sagging or attic stains. Often it only shows up once the old roofing is torn off.
Does every reroof need new decking?
No. Only boards that are damaged or unsuitable need replacing. Whole-roof resheeting is for widespread damage.
What is decking made of?
Usually plywood or OSB sheets. Some older homes have plank boards with gaps between them instead.
Related services
- Roof replacementComplete residential reroofing, from tear-off through the new roofing system.
- Roof inspectionsA slope-by-slope look at the roof and a plain answer about what needs attention.