How do you roof a garage?
Short answer. Roofing a garage follows the same sequence as a house: tear off to the deck, repair the sheathing, install drip edge and underlayment, then starter strip, shingles, flashing, and ridge cap, following the shingle manufacturer's nailing instructions. A detached garage with a simple gable roof is one of the more manageable roofing projects, but check the pitch and your local permit rules first.
Before you start
- Pitch: shingles need at least 2/12, with double underlayment between 2/12 and 4/12. Flatter garage roofs need a membrane system instead.
- Permit: many Georgia cities and counties require a permit for reroofing, even on detached buildings. See roofing permits in Georgia.
- Weather: plan for a dry stretch and have tarps ready for afternoon storms.
The sequence
- Tear-off: remove shingles, underlayment, and old nails down to the deck.
- Deck repair: replace soft or delaminated sheathing.
- Drip edge at the eaves: metal edge goes on first along the bottom edges.
- Underlayment: roll it out from the bottom up with proper overlaps. See synthetic underlayment vs felt.
- Drip edge at the rakes: installed over the underlayment along the sloped edges.
- Starter strip: along the eaves and rakes so the first course has a sealed edge.
- Shingles: start at the bottom, follow the manufacturer's offset pattern and nail placement, usually in the nailing strip.
- Flashing: step flashing where the roof meets a wall, plus pipe boots or vents as needed. See roof flashing explained.
- Ventilation and ridge cap: install a ridge vent if the garage has soffit intake, then cap the ridge.
Attached garages
Where a garage roof meets the house, valleys and wall intersections are where leaks start. That tie-in usually justifies professional help, and it is best done when the house roof is replaced so everything laps correctly.