Flat Roof Repair
Flat and low-slope roofs fail differently from pitched roofs. Water sits instead of running off, so small openings become leaks fast. GemSco repairs flat roofs on homes, additions, garages and commercial buildings.
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Where flat roofs are found
On homes, flat or low-slope sections usually cover porches, carports, additions, garages and modern designs. On commercial buildings, they are the norm: retail centers, offices, warehouses and multi-tenant buildings mostly sit under low-slope roofs because they are practical over large footprints and make room for HVAC equipment.
No roof is truly flat. A properly built low-slope roof has a slight pitch toward drains, scuppers or gutters. When that drainage fails, water stays on the roof, and that is where most flat roof problems begin.
Residential flat sections often get less attention than the main roof because nobody sees them. A porch or addition roof can hold water for years before the damage reaches the ceiling, so it is worth including those areas in every inspection.
Common flat roof problems
Ponding water
Water that stays on the roof long after rain adds weight and wears out the surface faster. It points to sagging decking, clogged drains or poor slope.
Open seams
Membrane seams and laps that separate let water travel under the roof covering, often far from where it shows inside.
Blisters and cracks
Trapped moisture or air and years of sun cause bubbles, cracking and alligatoring on the surface.
Flashing failures
Edges, walls, curbs and HVAC penetrations are where most leaks on low-slope roofs start.
Clogged drains
Leaves and debris in drains, scuppers and gutters keep water on the roof. See gutter repair for the edge drainage.
Punctures
Foot traffic, dropped tools, fallen limbs and hail can puncture membranes.
How GemSco repairs a flat roof
Inspection
We walk the roof, check seams, flashing, drains and penetrations, and look for wet areas and soft spots.
Photos
We photograph the problem areas so you or your property manager can see exactly what was found.
Written estimate
A written estimate that separates targeted repairs from wider work, if wider work is needed.
Repair
Patching, seam repair, flashing work, drain fixes or replacement of wet sections, using materials compatible with the existing roof.
Cleanup
We remove debris and old material from the roof and the property.
Flat roof systems we see most
TPO single-ply membranes, common on commercial buildings.
EPDM rubber membranes.
Modified bitumen, often on residential flat sections and smaller buildings.
Built-up roofs with layers of asphalt and felt.
Coated roofs and metal systems designed for low slopes.
Flat roofing for commercial buildings
On a commercial building, a leak is a business problem: damaged inventory, closed areas, tenant complaints. Low-slope roofs on these buildings carry HVAC units and other equipment, and every curb and penetration is a possible leak point. Regular inspections, clean drains and quick repairs to seams and flashing keep the roof working longer.
Access and safety also shape the job. Commercial roofs often need a planned route for materials, protection for walkways below, and coordination with HVAC technicians when units must be lifted or disconnected to reach the flashing underneath.
When repairs keep coming back, or wet insulation spreads under the membrane, it is time to compare repair against a new system. Our commercial roof repair page covers leak response for businesses, and commercial roof replacement explains how to plan a new roof. For the full picture, start at commercial roofing.
Flat roof repair across Texas
GemSco is family owned, fully licensed and insured, with more than 20 years of experience, and works on low-slope and flat roofs for homes and businesses. We serve Houston, DFW, Austin, San Antonio and surrounding areas, including Houston and San Antonio. Estimates are free.
Frequently Asked Questions
How long should water stay on a flat roof after rain?
A common rule of thumb is that water should drain or evaporate within about 48 hours in dry weather. Water that stays longer is ponding and points to drainage or structural issues. Ponding speeds up wear on the membrane and adds weight, so it is worth an inspection even if nothing leaks yet.
Can a flat roof be repaired instead of replaced?
Often, yes. Seams, flashing, punctures and drains can usually be repaired when the rest of the roof is sound. Replacement becomes the better option when the membrane is worn across the roof or the insulation underneath is wet over large areas. An inspection with photos shows which case you have.
Why does my flat roof leak in a spot far from the stain?
Water can travel under a membrane or along the deck before it finds a way inside. The opening might be at a seam, a curb or a wall flashing several feet away. That is why a flat roof repair starts with an inspection of the whole area, not a patch over the stain.
Should I coat my flat roof?
A coating can extend the life of a roof that is still sound, and reflective coatings help with heat. It is not a fix for wet insulation, open seams or failed flashing, which need repair first. Ask for an inspection before paying for a coating so you know what is underneath.
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GemSco Roofing & Solar serves Houston, DFW, Austin, San Antonio and surrounding areas. We’re family owned and fully licensed and insured.