What is roof decking?
What the deck does
- Nail base. Shingle nails must penetrate 3/4 inch into the deck or go all the way through it. A rotted deck cannot hold nails, and shingles blow off.
- Structure. The panels brace the rafters and turn the frame into a stiff diaphragm that resists wind.
- Load path. It spreads the weight of roofers, materials and the occasional North Georgia ice storm across the framing.
Typical decking on Georgia homes
Most homes built in recent decades have 7/16 inch OSB or 1/2 inch plywood in 4 by 8 foot sheets. Many older homes have board decking, 1x6 or 1x8 planks, sometimes with gaps between them. Mountain cabins sometimes have tongue and groove planks that double as the finished ceiling.
When decking gets replaced
During a replacement, the old shingles come off and the crew walks the deck. Soft, rotted, delaminated or water damaged sheets are cut out and replaced. A good contract lists a per-sheet price for decking up front, because no one can see it until tear-off. Full redecking happens when board decking has wide gaps or the damage is widespread. In an insurance claim, decking damaged by the covered loss can be added through a supplement.
Not a porch deck
If you were looking for a roof over an outdoor deck, that is a porch or patio cover, a separate project with its own framing and usually its own permit.