Serving Kansas City and nearby areas
A seam that has split or lifted is an open door for water on a flat roof, so get a free roof inspection and a written seam repair price set up the same day you call.
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Need help sooner? Call (913) 347-6527.
We connect property owners in Kansas City and nearby areas, including Fairfax District, Armourdale, Village West, Edgerton, Lenexa and Olathe, with one independent local commercial roofing specialist.
Hot to cold, all year
Kansas City runs from normal July highs near 89 degrees to January lows near 19 to 21 degrees. A roof sheet grows and shrinks through that swing, and seams take the strain.
Old glued seams
Federal researchers at NIST studied rubber roof seams after industry surveys in the 1980s found glued seams failing and causing leaks. Seam tape is now seen as far more reliable.
Typical published ranges for Kansas City. The contractor's written estimate is the price, and the inspection is free.
| Work | Typical range |
|---|---|
| Roof inspection and written priceSet up through Kansas City Commercial Roofers | Free |
| Seam repair | $200 to $1,000 |
| Flashing repair | $200 to $750 |
| Most flat roof repairs | $300 to $1,100 |
| Membrane repair | $250 to $1,750 |
A flat roof is made of wide sheets joined at seams. The sheet itself is tough. The seams are where it is most likely to fail. When a seam splits or lifts, water can run straight under the roof. It soaks the insulation and drips out wherever it finds a low spot inside.
Seam trouble is one of the most common reasons a Kansas City flat roof leaks. The good news is that a seam caught early is a small repair.
A seam edge that curls up
Or flaps in the wind.
A gap
You can see or slide a finger into.
Dark lines
Of dirt along a seam where water sits.
Wrinkles or fishmouths
Small open tunnels at the edge of a seam.
Old caulk or tar
Smeared along a seam from past patches.
Sheet pulled tight
At the edges, with corners or walls tugged out of shape.
Leaks in a straight line
Inside, following the run of a seam.
Rubber (EPDM) roofs. Many older black rubber roofs were seamed with liquid glue. In the 1980s, industry surveys found those glued seams failing and causing leaks. Federal researchers at NIST studied the problem, and the industry changed its methods. Today most rubber seams use seam tape, which holds up far better. Older glued seams are still out there on many buildings. Seams also fail when the rubber was not scrubbed clean before seaming, or when an aging sheet shrinks and pulls on its seams.
White (TPO) roofs. TPO seams are welded with hot air. A good weld is strong. One studied group of aged TPO roofs had seam welds that held up well after years in service. Problems come from welds that were too cold, too hot, too narrow, or done over dirt or moisture. Makers tell crews to check every weld with a probe. A missed bad weld can open up years later.
Tar and modified bitumen roofs. Laps between rolls can lose their bond with heat and age, mostly where blisters form near the edge of a lap.
Big swings in heat and cold. Normal July highs in Kansas City reach about 89 degrees, and a roof gets much hotter than the air. Normal January lows sit near 19 to 21 degrees. The sheet grows in the heat and shrinks in the cold, every day and every season. The seams take that strain.
Wind. Strong storm winds are common. Once a seam edge lifts, wind can get under it and peel it further.
Hail. Kansas City, Kansas, has been ranked among the top hail-prone metros in the US. Hits along a seam can weaken it.
Can wait for a routine check: a tiny edge lift on a short stretch, with no gap and no stain inside.
Book an inspection soon: a seam you can see into, seams with old caulk patches, or wrinkles and fishmouths.
Call the same day: an open seam with water coming in, a seam peeling back in the wind, or a long split.
Clean, prime and re-bond
For rubber roofs, the crew cleans the seam, primes it and bonds it again with seam tape.
Cover strip
A new strip of membrane goes over the old seam to seal it.
Re-weld
For TPO, the crew cleans the sheet and welds the seam again with hot air, then probes it.
Patch the lap
For tar and modified bitumen, a new piece of roofing gets set over the failed lap.
Replace wet insulation
Under a seam that leaked for a long time.
The crew should follow the roof maker's repair method so any warranty stays in good standing. National cost guides put seam repair at about $200 to $1,000. If seams are failing all over an older roof, the inspector may tell you a new roof or a recover is the better spend. Your price comes in writing after the inspection.
Do not caulk over it
It hides the problem and makes the real repair harder.
Take photos
Of the seam and any stains inside below it.
Note the roof type
If you know it: black rubber, white sheet, or gritty rolled roofing.
Find the roof's age
Warranty and past repair records.
Keep staff off the roof
In wind or wet weather.
Call (913) 347-6527 or send the form. Kansas City Commercial Roofers sets up the inspection with one independent local roofing contractor, and you get a written price.
Older rubber roofs often used liquid glue at the seams. Glue ages and lets go. Seams also fail when the rubber was not cleaned well before gluing, or when the sheet shrinks and pulls on them. Newer seam tape holds up better.
Caulk on top of a lifted seam does not last. The seam has to be cleaned, primed and bonded again, or covered with a new strip, using the roof maker's method. Caulk is a stopgap at best.
Look for edges that lift, wrinkles, or gaps along the seam line. A crew checks TPO seams with a probe, a small hand tool run along the edge. On a good weld, the tool will not slip into the seam.
National cost guides put seam repair at about $200 to $1,000. A roof with many failing seams costs more, and at some point a new roof or a recover may make more sense.
Not always. One or two failed seams on a sound roof are a repair. Seams failing all over an older roof, with wet insulation under them, can mean the roof is near the end.
