Service
Roof deck builders in Philadelphia
A new roof deck on a Philadelphia rowhome is part carpentry, part structure, part roofing. Here is what a builder will look at, what the City requires, and what it tends to cost.
- Free to use
- Independent Philadelphia builders
- Plain-English zoning & permit help
What a roof deck build involves
Philly Home Collective’s Fishtown guide breaks a typical project into the same pieces most quotes will:
- Design and engineering: drawings, plus structural calculations stamped by a licensed design professional when reinforcement is needed
- Structure: reinforcing the roof framing or adding new framing to carry the deck
- Roofing and waterproofing: often replacing or upgrading the flat roof before the deck goes on top
- The deck itself: framing or pedestals, decking or pavers, railings
- Access: a pilot house, hatch or stair. Pilot houses
- Extras: lighting, outlets, a gas line, planters, privacy screens
Zoning limits
| Rule (Zoning Code § 14-604(5)) | What it says |
|---|---|
| Where allowed | Roof decks are permitted for residential uses in all zoning districts, but not on accessory structures such as garages |
| Front setback | At least 5 ft back from the front building line, unless the top story is already set back 5 ft |
| Deck height | No part of the deck surface more than 48 in above a plane midway between the roof’s lowest and highest points |
| Railings | Guard rails or fences no taller than 42 in; privacy screens up to 60 in and no more than 50% opaque on the sides, within 18 in of a side lot line |
| Access structure (pilot house) | May only enclose the stairs, elevator or other access; max 125 sq ft (+40 sq ft with an elevator) outside RM-2, RM-3, RM-4, RMX-3, CMX-3, CMX-4, CMX-5 and IRMX; max 10 ft above the deck |
| Access structure setbacks | Same setback as the deck, plus 5 ft more for any part over 42 in above the deck; 5 ft from the rear building line |
Permits you should expect
- A building permit, always. L&I’s EZ deck standard, which lets small rear-yard decks skip plans, says a deck “may not be located above the 1st floor” and that “a separate building permit is required for roof decks.”
- Zoning approval. The City says zoning approval is required for additions, and that for small projects, such as additions to single-family homes, L&I can review zoning and building together if you file a building permit application.
- Historical Commission review if the house is on the Philadelphia Register. The City lists “decks” and “roofing and flashing” among the exterior work that needs a project review. More.
- A licensed contractor. Philadelphia requires a Contractor License for construction businesses. Firms that only work on existing one- and two-family homes instead register with the State as Home Improvement Contractors and submit that way, per the City.
Railings and guards
Zoning caps deck guard rails at 42 inches. The building code sets the minimum and the details: L&I notes that the 2021 residential code added specific deck guard requirements, including a load path from the guard to the joists or blocking, limits on end-grain fasteners, and resistance to rotation where guards attach to the side of a joist. Philly Home Collective adds that rooftop wind loads can be higher, so posts and anchors need engineered connections.
Decking materials
| Material | Per sq ft (HomeAdvisor, national) |
|---|---|
| Pavers or tiles | $16–$25 |
| Pressure-treated wood | $25–$50 |
| Cedar or redwood | $30–$55 |
| Composite | $40–$80 |
HomeAdvisor puts labor at $13–$30 per square foot. Full cost guide.