How much does flat roof repair cost in the Chicago suburbs?
Most flat roof repairs we do fall between $300 and $10,000. The low end is a single seam, a blister, or a failed flashing at a wall or a vent. The high end is cutting out and rebuilding a wet section of roof, insulation included, or re-flashing a long parapet. Full replacement of a commercial or multi-family flat roof typically runs $25,000 to $75,000 depending on size, tear-off layers and drainage work. We give a written estimate after looking at the roof, because the price depends on what is under the membrane, not just the area.
What is a tar roof, and can it still be repaired?
A tar roof usually means a built-up roof (BUR): layers of felt and hot asphalt or coal tar, often finished with gravel. Many Chicago-area two-flats, apartment buildings and older commercial buildings still have one. They can be repaired when the problem is local, such as a blister, a split at a wall, or a failed drain. Once the felts are dried out across the roof, water gets between the layers and patches stop holding, and replacement with modified bitumen or TPO is the better money. Gravel has to come off first; our roof gravel removal page explains how that works.
How long does a flat roof last in the Chicago area?
Roughly: built-up tar and gravel 20 to 30 years, modified bitumen 20 to 25 years, TPO 20 to 30 years, EPDM 25 to 30 years. Freeze-thaw cycling, ponding water and foot traffic shorten all of them. Most flat roofs fail at the edges first: walls, parapets, drains, curbs and penetrations. That is why flashing work matters more to the life of a flat roof than the brand of membrane.
Which flat roof system is best: modified bitumen, TPO or EPDM?
It depends on the building. Modified bitumen handles foot traffic, rooftop equipment and small roofs with lots of edges well, so it suits garages, porches, additions, two-flats and busy commercial roofs. TPO is a white heat-welded membrane that is economical on large open roofs and reflects heat, which matters inside Chicago where the energy code expects reflective low-slope roofs. EPDM is a rubber membrane that is durable and simple but dark. We recommend one after seeing the roof, and we put the system, thickness and warranty in the written estimate.
Do you do residential flat roofs or only commercial?
Both. Most houses around Chicago have a flat or low-slope section somewhere: a rear addition, a porch, a garage, a dormer tie-in, or the whole roof on a two-flat or a mid-century home. These small roofs leak for the same reasons big ones do, at the edges. We also work on condominium and apartment buildings and on commercial buildings from strip centers to light industrial.
Can a flat roof be repaired in winter?
Emergency repairs, yes. We can stop an active leak in winter with materials rated for cold application. Full replacement is best done when the deck is dry, usually April through November, because torching or adhering a membrane over a wet or frozen deck traps moisture and causes blisters. If a roof needs replacing in winter, we patch it to get through and schedule the replacement for the first reliable dry stretch.
Should ponding water on a flat roof worry me?
Water that is still standing 48 hours after rain is a problem. It speeds up membrane wear, adds weight, and finds every weak seam. The usual causes are a clogged or poorly placed drain, a sagging deck, or insulation that has compressed. The fix can be as simple as clearing a drain or adding a scupper, or it can mean tapered insulation during replacement. We note ponding on every inspection.
Do you work on condo and apartment building roofs?
Yes. Multi-family flat roofs are a large share of the flat roof stock around Chicago. For associations we provide a written condition report with photos, a repair-or-replace recommendation, and a scope the board can compare against other bids. Our condo and HOA roof decision guide covers how boards usually approach it.
