Flat and low-slope roof repair and replacement in Miami, FL

A large share of Miami-Dade roofs are flat or nearly flat: the addition on the back of a 1960s ranch house, the garage, the Florida room, whole townhouse rows in Kendall and Doral, and most of the small commercial buildings along the avenues. They are built and fail differently from the pitched tile and shingle roofs the county is known for, and a contractor who does mostly tile is not automatically the right one for a membrane.

Say what you see and how old the roof is. The roofer looks first, tells you in writing what they found, and quotes a repair or a replacement with a price and a warranty. What you do with it is up to you.

Need a roofer? Call 786-353-7450

Why flat roofs leak

• Ponding: water that still sits on the roof 48 hours after rain. A flat roof is supposed to have enough slope to drain; where it does not, the membrane sits in water and ages there first. Clogged scuppers and drains cause most of it.
• Seams and edges: modified bitumen and TPO are sheets joined by heat or adhesive, and the seams and the metal edge (drip edge, parapet cap) are where they open. A leak "along the wall" is usually the flashing where the flat roof meets a higher wall.
• Penetrations: every vent pipe, AC stand, satellite mount, and skylight is a hole someone sealed. The sealant lasts a few years in Miami sun; the roof lasts fifteen or twenty.
• Foot traffic: AC technicians, pressure washers, and antenna installers walk flat roofs. Membrane punctures and cracked tiles on the pitched section are the common result.
• Age: a built-up or modified bitumen roof from the last replacement cycle is now at the end of its life across much of the county. Alligatored, brittle surfacing and bare spots are the signs.

Repair or replace

A seam, a flashing, or a penetration on an otherwise sound membrane is a repair, done with a patch of the same material heat-welded or adhered, and it should come with a written warranty on that spot. Chronic ponding, a membrane that is brittle everywhere, or wet insulation under the surface (a contractor can find that with a moisture meter or an infrared scan) is a replacement. The 25 percent rule still applies to older flat roofs: replacing more than a quarter of a roof section within a year means re-roofing that section to current code, which for a flat roof usually means new insulation with slope built in, new drains or scuppers, and a new membrane, permitted and inspected. Since 2022 (Florida Statute 553.844(5)), for a roof or roof section built, repaired, or replaced in compliance with the 2007 Florida Building Code or a later edition, in practice one installed after March 2009, only the portion being repaired, replaced, or recovered must meet the applicable current code; the rest of the section does not have to be redone.

The materials you will see on the quote

• Modified bitumen (mod-bit, "torch-down" or self-adhered): asphalt sheets in two layers, granulated or coated on top. The common residential flat roof in Miami-Dade; durable, repairable, familiar to every crew.
• TPO: a white single-ply membrane, heat-welded at the seams, reflective and cooler. Common on newer townhouses and commercial; lower cost per square, but the seams and the crew’s welding matter more than the brand.
• Built-up (BUR, "tar and gravel"): layers of felt and asphalt under gravel. Mostly older commercial; rarely installed new, often replaced with mod-bit or TPO.
• Coatings: a silicone or acrylic coating over an existing sound roof buys years and reflects heat. It is not a fix for a wet roof or a failed membrane, and a contractor who leads with a coating on a leaking roof is skipping the diagnosis.

What a proper flat-roof job includes

• A permit from your city or Miami-Dade RER and the inspections that go with it; the notice of acceptance (NOA) number for the product, which is Miami-Dade’s own approval.
• Slope: tapered insulation or crickets so water reaches the drains, and drains or scuppers sized and placed to take it. A new roof that still ponds was not designed, only covered.
• Flashing at every wall, edge, and penetration, with the metal edge and any parapet cap replaced, not caulked over.
• A written warranty from the contractor on labor, separate from the manufacturer’s warranty on the material, and what each covers.

What drives the cost

We do not set or quote prices. The contractor’s number depends on the area (flat roofs are priced by the square, 100 sq ft), the material, whether wet insulation and decking have to come out, how much slope has to be built, how many penetrations and how much wall flashing there is, and access for the crew and the dumpster. A written proposal comes after they have been on the roof; price, timing, and warranty are between you and the contractor.