Flat & Low-Slope Roofing Systems (TPO & Modified Bitumen)

Low-slope roofs demand professional drainage planning and proper waterproof detailing. The single biggest performance factor is positive drainage—designed structurally or created with tapered insulation.

Why Flat Roofs Fail (and How We Prevent It)

Most flat roof issues come from:

• Standing water (ponding)

• Poorly detailed penetrations

• Improper wall transitions/termination

• Incompatible repairs or coatings

• Weak drainage design (not enough slope)

Flat roofs must drain. If water sits, failure accelerates.

Positive Drainage (Non-Negotiable)

Positive drainage can be created in two ways:

Option A: Structural Slope (best during new construction)

The building is framed with a slope so water moves to the drains/scuppers.

Option B: Tapered Insulation (ideal during reroofing)

We add tapered insulation to build a slope without changing the structure.
This improves:

• Drainage

• Energy performance (insulation upgrade)

• Roof lifespan (less ponding)

System Option 1: TPO Roofing

TPO is a heat-welded single-ply membrane commonly used for:

• Commercial buildings

• Multi-family

• Modern residential low-slope sections

Key benefits:

• Heat-welded seams (monolithic waterproofing)

• Strong UV resistance

• Reflective surface (energy savings)

• Clean, professional finish

Manufacturers commonly used in Florida:

• GAF

• Carlisle

• Johns Manville

• Firestone / Elevate

• Mule-Hide

System Option 2: Modified Bitumen (SBS/APP)

Mod-bit is a multi-layer asphalt-based system ideal for:

• High-traffic roofs

• Complex detail areas

• Certain coastal commercial applications

Key benefits:

• Robust puncture resistance

• Great detail performance when built correctly

• Multiple assembly options (torch, self-adhered, cold process)

• Excellent redundancy (layered protection)

Manufactures we use:

• GAF

• Johns Manville

• CertainTeed

• Polyglass

• Soprema (often used in waterproofing contexts)

Flat Roof Detailing: We Prioritize

• Drain/scupper design and placement

• Parapet and wall transition terminations

• Penetration boots and pitch pans (as required)

• Walk pads where maintenance access is expected

• Moisture scanning before overlays when applicable

Schedule a Flat Roof Inspection

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