Flat & low-slope roofs
Flat roof repair and replacement in North Jersey
4.9 stars on Google60+ reviewsFamily-owned12 years of roofing experience
Porches, additions, dormers, garages and multi-family homes all have low-slope sections where shingles do not belong. We repair and replace flat roofs with the four membrane systems that work in our climate, and we help you pick the right one.
The basics
Why flat roofs leak
No roof is truly flat. A “flat” roof is a low-slope roof that should fall at least a quarter inch per foot toward a drain, scupper or gutter. Shingles rely on gravity to shed water and are not made for slopes that low. A flat roof needs a continuous waterproof membrane instead.
Flat roofs leak for a short list of reasons:
- Seams that have opened up with age or were never sealed well
- Flashing at walls, parapets, skylights, vents and where the flat roof meets a shingled slope
- Ponding water from sagging framing, poor slope or clogged drains
- Punctures from foot traffic, tools, branches and old satellite mounts
- Age. Old tar-and-gravel and rolled roofing dry out, crack and blister
Compare systems
TPO, PVC, EPDM or modified bitumen?
| System | What it is | Strengths | Best for |
|---|---|---|---|
| TPO | White single-ply sheet. Seams are welded with hot air. | Welded seams are stronger than the sheet itself. Reflects summer heat. Good value. | Most commercial roofs and larger residential flat roofs. |
| PVC | Single-ply sheet, also heat-welded. A different plastic from TPO. | Resists grease, oils and many chemicals. Long track record. | Restaurants, food businesses and roofs with kitchen exhaust. |
| EPDM rubber | Black synthetic rubber sheet. Seams are joined with tape and primer. | Stays flexible in deep cold. Large sheets mean few seams. Decades of proven service. | Small to mid-size roofs, porches, additions and garages. |
| Modified bitumen | Asphalt sheets reinforced and modified with rubber or plastic, installed in two or more plies. | Thick and tough underfoot. Handles foot traffic and hard use. | Small residential flat roofs, balconies and roofs people walk on. |
There is no single best membrane. The right choice depends on the size of the roof, what is on it, what is under it and how it is used.
Where flat meets steep
The tie-in is where most house leaks start
On a house, the flat section almost always meets a shingled slope, a wall or a dormer. That joint is the hard part. We:
- Run the membrane up under the shingles far enough that water cannot back up past it
- Turn the membrane up walls and finish it with proper metal counter-flashing
- Rebuild rotted decking and add tapered insulation where the roof holds water
- Flash skylights, vents and posts with factory-made or field-welded boots, not just sealant
- Make sure water has a clear path to a drain, scupper or gutter
Our work
Flat roofs and decks, job by job
A modified bitumen flat roof replacement under way, and a terrace deck finished with pavers over new EPDM waterproofing. Click or tap any set to see it full size.
View this photo set full size (opens in a new tab)Top: the worn old flat roof. Bottom: the old roof is off and new modified bitumen membrane is going down roll by roll. 
View this photo set full size (opens in a new tab)A terrace deck: new EPDM waterproofing membrane, details sealed at the walls, then pavers set over the top.
Questions
Flat roofing questions
How long does a flat roof last?
With correct installation and drainage, single-ply membranes such as TPO, PVC and EPDM commonly last 20 to 30 years, and EPDM often longer. Modified bitumen typically lasts 15 to 20 years or more. Ponding water, foot traffic and neglected drains shorten any of them.
Can a flat roof be repaired, or does it need to be replaced?
If the membrane is in fair shape and the insulation below is dry, targeted repairs to seams, flashing and punctures work well. If the insulation is soaked, the membrane is brittle or leaks are everywhere, replacement is the honest answer.
Is standing water on my flat roof a problem?
Water that is still there 48 hours after rain is ponding. It ages the membrane, adds a lot of weight and finds any weak seam. We fix it with better drainage or tapered insulation.
Do you coat flat roofs?
We coat commercial flat roofs only. On a home, we repair or replace the flat roof instead.
Do I need a permit for a flat roof on my house?
Replacing the roof covering on a detached one- or two-family house does not need a construction permit in New Jersey. Multi-family and commercial buildings do, and so does any job where roof sheathing is replaced. We check with your town.
Related services
Flat roof leaking or holding water?
We will find the cause, show you photos and price the fix.