Tracing Leaks Through Ann Arbor's Freeze-Thaw Cycle
The scope documents leak sources, repair boundaries, photos, and priorities so Ann Arbor owners can separate immediate stabilization from longer-term capital work. A leak call on a commercial roof rarely starts where the water shows up inside the building. Water travels along deck flutes, down conduit runs, and across suspended ceilings before it finds a spot to drip, so the first job on every leak repair is mapping the path backward to the actual entry point on the roof.
Ice Dam Backups Behind Parapets and Curbs
Ann Arbor winters produce repeated freeze-thaw cycles rather than one long deep freeze, and that repetition is what drives ice dam formation on flat and low-slope commercial roofs. Snow melts slightly during a warm afternoon, runs toward a drain or scupper, then refreezes overnight when temperatures drop again. Over several cycles, ice builds up against parapet returns, curb bases, and drain bowls until meltwater has nowhere to go but under the membrane at a seam or flashing edge.
We look first at exactly those spots: parapet-to-deck transitions, curb corners, and drain bowls, because that's where ice dam backup pressure finds the weakest detail rather than failing the field membrane itself.
Seam and Flashing Failure From Repeated Cold Cycling
Membrane seams that were welded or adhered correctly at installation can still fail years later from repeated cold-weather contraction. Every freeze cycle pulls the membrane taut; every thaw relaxes it. On older EPDM roofs especially, that cycling gradually works lap seams loose at the edges, and pipe boot flashings that were pliable when new can crack once the rubber compound stiffens with age and UV exposure. We probe every suspect seam by hand rather than relying on a visual pass, since a seam can look intact and still separate under finger pressure.
Wind-Driven Rain From Summer Thunderstorm Cells
Southeast Michigan's summer storm pattern includes fast-building thunderstorm cells and occasional derecho-style straight-line wind events that push rain sideways against parapets, wall panels, and rooftop unit curbs. A detail that sheds vertical rain without issue can leak during a wind-driven event if counterflashing has come loose or a wall panel joint has opened up. We ask about the weather conditions present when a leak first appeared, since a leak that only shows up during specific wind directions points us toward a specific wall or parapet face rather than a roof-wide problem.
What a Leak Investigation Actually Covers
- Interior water-path tracing from the reported leak location back toward the roof
- Hand-probing of seams, laps, and flashings in the suspect zone rather than a visual-only walk
- Drain and scupper inspection for ice damming or debris blockage upstream of the leak
- Moisture scanning where repeated leaks suggest wet insulation spreading beneath the membrane
- Photo documentation of every deficiency found, whether or not it's the active leak source
- A written repair scope separating the confirmed leak fix from other deficiencies worth planning for
Repair Versus the First Sign of a Bigger Problem
Some leak calls end with a straightforward flashing repair. Others turn up wet insulation spreading well beyond the reported leak, which changes the conversation toward a recover or tear-off rather than another patch. We tell owners which situation they're in rather than defaulting to the smaller, cheaper fix when the roof's condition doesn't support it. Where the roof is approaching that decision point, our commercial roof inspection page covers how we scope that broader assessment.
Temporary Mitigation While a Repair Is Scheduled
Not every leak gets fixed the same day it's reported, especially if the repair needs material that isn't already on the truck or access to a roof section that's blocked by rooftop equipment. In those cases we set temporary mitigation, sometimes a mechanically secured patch, sometimes interior water diversion above a ceiling grid, so the building isn't absorbing ongoing damage while the permanent repair gets scheduled. We tell the property manager exactly what the temporary fix is holding back and how long it's rated to last.
Leaks That Trace Back to Rooftop Equipment
Not every leak originates at the membrane or flashing itself. HVAC condensate lines that discharge onto the roof surface instead of into a proper drain, curb gaskets on rooftop units that dry out and crack, and mechanical penetrations added after the original roof installation are common leak sources that get missed when an investigation focuses only on membrane and seam condition. We check every piece of rooftop equipment as part of a leak call, in addition to the roofing assembly around it, since a mechanical contractor's penetration is often the actual cause of a leak the roof gets blamed for.
When a Leak Points to a Design Problem, Not a Failure
Some recurring leaks aren't a failed repair at all, they're a roof detail that was never adequate for how the building is actually used. A drain that was fine for the original tenant's equipment load but now sits under a walkway worn by daily foot traffic, or a curb that predates rooftop solar and wasn't flashed for the added penetrations, both fall into this category. We flag design-level issues honestly rather than repeating patches on a detail that needs to be rebuilt correctly the next time it's opened up.
Leak Repair Questions From Ann Arbor Property Managers
Why does our roof only leak in winter?
That pattern usually points to ice dam backup at a parapet, curb, or drain rather than a membrane puncture. Meltwater from freeze-thaw cycling finds its way under flashings that hold up fine against normal rainfall.
Can a leak be fixed without a full roof replacement?
Often, yes, if the moisture is contained to a specific detail. We scan and probe before recommending scope so the repair matches what's actually wrong rather than over-scoping or under-scoping the fix.
How fast can you respond to an active leak?
Active leaks during business hours get priority scheduling, and we can typically get someone on the roof for initial assessment and temporary mitigation within the same day for buildings in the Ann Arbor service area.
Does the university or a hospital building need special handling for leak repairs?
Yes. Lab and clinical roofs need coordination around exhaust systems, sensitive equipment, and occupied space below, so we scope access and timing around the building's operational schedule rather than a standard commercial timeline.
What if the leak keeps coming back after a repair?
A recurring leak at the same spot usually means the underlying cause, like an ice dam pattern or a failing curb detail, wasn't addressed by the original patch. We reinvestigate with fresh eyes rather than repeating the same repair.