A brown ring on the ceiling under your addition gets a little bigger after every storm, or the garage drips in one spot whenever it rains hard. You’ve been up on the flat roof and maybe seen a puddle, a bubble or a crack, but you’re not sure what’s causing the leak. Flat roof repair in Republic, MO starts with finding the actual cause, because a patch over the wrong spot just buys you another stain.
Low-slope roofs are confusing. Water moves slowly across them, gets under the membrane and can travel a few feet before it drips through, so the leak inside often isn’t directly below the problem. You don’t want to keep paying for guesses.
APC Roofing repairs and replaces flat and low-slope roofs on homes and light commercial buildings. We’re GAF Certified, licensed and insured, and your inspection is free. Call 913-398-5020 to get your flat roof checked.
What’s causing your flat roof to leak
Most flat roof leaks on homes come from one of the problems below. Matching the symptom to the cause is the first step to a repair that holds.
Water that sits for days
Some water after a storm is normal. Water still standing two days later means a low spot, a sagging deck or a blocked drain or gutter. Standing water ages the membrane faster, adds weight and finds any weak seam. In winter, it freezes and expands. Fixing ponding sometimes takes more than a patch, such as building up the low area or clearing the path the water should take.
Bubbles and blisters
A blister is a pocket where the membrane has lifted off the layer below, usually because moisture or air got trapped and expanded in the heat. A small, intact blister isn’t always an emergency. One that’s cracked, growing or soft underfoot needs attention, since it can mean water is already under the roof.
Split seams and open laps
Seams are where sheets of roofing join. Old adhesive dries out, tape lets go and asphalt laps on older roofs turn brittle and open up. Freeze-thaw cycles in a Missouri winter widen any gap a little more each time. A lifted seam is one of the most common sources of a flat roof leak.
The joint where the roof meets the house
On porches and additions, the most common leak isn’t on the flat roof at all. It’s at the wall where the roof meets the house, or at the line where the low roof meets a shingle roof. Flashing that has pulled away, siding that wasn’t lapped over the flashing or a membrane that doesn’t run far enough up the wall all let water in right there.
Cracks, punctures and hail
Older built-up and modified bitumen roofs crack in a pattern that looks like alligator skin once the surface dries out in the sun. Hail can bruise or puncture a membrane, especially older or thinner ones. Branches, dropped tools and people walking on the roof leave small cuts that grow over time.
Clogged edges and gutters
Leaves and grit pile up where a flat roof drains. If the gutter or scupper at the low edge is blocked, water backs up onto the roof and finds its way under the edge metal.
Making a repair that lasts
A good flat roof repair uses material that matches the roof. TPO gets a welded TPO patch after the old surface is cleaned. EPDM gets compatible membrane and seam tape. Built-up and modified roofs get matching asphalt-based materials. Mismatched materials and a quick bead of caulk are two of the most common reasons repairs fail within a season.
Most repairs also need a dry, clean surface, and some materials won’t bond well in cold weather. If water is coming in during a storm, a temporary fix may come first, with the lasting repair once the roof dries out.
If the decking under the leak is soft, that wood has to be replaced. Patching over rotten wood doesn’t hold, and the soft spot usually grows.
Repair or a new flat roof?
A repair is usually the right call when the roof is in decent shape and the problem is in one area. A new roof makes more sense when:
- The roof was built with shingles or rolled roofing on a slope that’s too shallow for them
- Water ponds across large areas, not just one low spot
- The decking is soft in several places
- The roof has already been patched many times and keeps leaking
Our flat roof installation in Republic page explains what goes into a new low-slope roof, and the TPO roofing in Republic page covers the most common replacement membrane. If your leak is on the main pitched roof instead, see roof leak repair in Republic.
Storm damage and insurance
If hail or wind damaged your flat roof, you file your own claim with your insurance company and pay your own deductible. We inspect and photograph the damage, write up an estimate and work with your adjuster. Be wary of anyone who offers to waive or cover your deductible.
How it works
- Book your free inspection. Call 913-398-5020 or request a free estimate online. Tell us where the water shows up inside.
- Get a clear, honest assessment and estimate. You’ll see photos of what’s causing the leak, hear whether a repair will hold and get a written estimate.
- The repair gets done and the site gets cleaned up. The repair is made, and the area is cleaned up before the crew leaves.
A small leak on a porch or garage roof can seem minor. Left for a few seasons, it can soften the decking and the ceiling below, and a one-spot repair turns into a new roof plus carpentry.
Flat roof repair questions
Can a flat roof be repaired, or does it need replacing?
Many can be repaired, especially when the problem is a single seam, a flashing detail or a small damaged area. Replacement makes more sense when the problems are spread across the roof or the decking is soft.
Why does water pool on my flat roof?
Usually a low spot in the deck, framing that has sagged over time or a blocked drain or gutter. A little water that dries within a day or two is normal.
Is a blister on my flat roof a problem?
A small, unbroken blister may not be. One that’s cracked, spreading or soft underfoot should be checked, since water may already be under the membrane.
Can you repair a flat roof in winter?
Some repairs can be done in cold weather, and some materials need warmer, dry days to bond. If water is coming in, a temporary fix can hold until conditions allow a lasting repair.
Get flat roof repair in Republic, MO
Call 913-398-5020 or book your free inspection online. You’ll know what’s causing the leak and whether a repair will hold before you spend anything. Then you can stop watching the porch ceiling every time it rains.
