Flat Roof Replacement in Coral Gables

Every replacement starts with a full inspection. We check the deck for soft spots, water damage, and structural issues that need fixing before the new membrane goes down. If the deck is compromised, we fix it: putting a new membrane over damaged substrate leads to failure within months.

We verify drainage slopes during tear-off. Flat roofs aren't actually flat: they need a minimum slope to move water toward drains or scuppers. If the slope is inadequate, we install tapered insulation to create proper drainage. Standing water shortens membrane life and creates leak risk.

Membrane installation follows manufacturer specs and Miami-Dade County's fastening requirements. We use mechanically-attached or fully-adhered systems depending on wind exposure and membrane type. Seams are heat-welded or chemically bonded. Edge metal, flashing, and penetration details are sealed and fastened to resist wind uplift.

The final step is a water test. We flood-test the roof or run hoses across the surface to verify that water drains and no leaks exist at seams, penetrations, or edges. This catches problems before we leave.

TPO (thermoplastic polyolefin) is the most common flat roofing membrane in South Florida. White TPO reflects heat, which cuts cooling costs and extends membrane life. It's heat-welded at the seams. TPO handles UV well and resists algae. Typical lifespan is 15+ years depending on thickness and maintenance.

Modified bitumen is a rubberized asphalt membrane that works well in hot climates. It's installed in multiple layers with torch-applied or cold-adhesive methods. Modified bitumen is more puncture-resistant than TPO, which matters if you have roof equipment or foot traffic. It comes in reflective white or granulated surfaces. Lifespan is 15+ years with proper maintenance.

EPDM (rubber membrane) is less common in Coral Gables but still used on some roofs. It's a black membrane that absorbs heat, which increases cooling costs compared to white TPO. EPDM is durable and handles temperature swings, but seams are glued rather than heat-welded, so they need careful sealing.

We help you compare these based on your roof's size, exposure, and how you use the space. If you have rooftop HVAC equipment, we talk about puncture resistance and walkway pads. If energy efficiency matters, we explain reflectance ratings and how they affect cooling costs.

Coral Gables sits inside the Miami-Dade High-Velocity Hurricane Zone, which requires every membrane assembly to carry a Notice of Acceptance covering the specific combination of deck type, insulation, membrane, and fastener pattern. Substituting any single component voids the NOA, so we install each system exactly as approved and reference the assembly number on the permit drawings.

TPO and PVC systems in HVHZ applications use either mechanically attached or fully adhered methods depending on the deck. Mechanically attached TPO over wood deck typically requires fasteners on 6 to 12 inch centers along the seam, with closer spacing at perimeter and corner zones where uplift pressures are highest. The perimeter zone extends 10 percent of the roof width inward from the edge; the corner zone occupies the outer 10 percent at each corner. Both zones use roughly twice the fastener density of the field zone.

Modified bitumen in HVHZ applications uses a two-ply or three-ply assembly torch-applied or cold-adhered to a base sheet that is mechanically fastened or fully adhered. The cap sheet's granulated surface protects the underlying modified asphalt from UV and provides walking traction for service crews. Modified bitumen handles ponding water better than single-ply systems, which matters on roofs where drainage is marginal.

Drainage design follows the 1/4 inch per foot minimum slope toward primary drains, with secondary scuppers placed 2 to 4 inches above the primary drain inlet to handle overflow during heavy rainfall events. Ponding-water remediation on existing roofs typically uses tapered polyisocyanurate insulation to build slope toward drains; we field-cut the tapered panels to match the existing roof geometry and verify the finished slope with a water test before installing the membrane. Scupper sleeves and drain bowls are flashed with prefabricated boots compatible with the membrane chemistry, sealed at the membrane interface and mechanically clamped at the deck.

We're certified applicators for Tremco, Sika, and PolyGlass flat roofing systems. These certifications require training on proper installation methods, fastening patterns, and seam-sealing techniques specific to each manufacturer's products. Certified installation is often required to activate the manufacturer's material warranty.

Our workmanship warranty covers installation for up to 12 years. This warranty is separate from the manufacturer's material warranty and covers labor, fastening, and seam integrity. If a leak develops due to installation error, we repair it at no cost to you.

All warranty coverage is subject to the terms and conditions outlined in the written warranty document provided at project completion. Warranty claims require proper maintenance and periodic inspections as specified in the warranty terms.

Homeowners weighing alternatives to a flat-roof replacement on a mixed-pitch home often consider the pitched sections separately. We also install Coral Gables metal roofing profiles such as aluminum roofing in Coral Gables and Galvalume roofing in Coral Gables on the steep-slope portions of the same building. The full neighborhood scope of materials and services we install is documented on Istueta's Coral Gables service area page.

For more information about flat roof replacement, see our flat roofing guide and roof replacement overview.