Commercial Roofing
A clinic waiting room with a ceiling stain beside an exterior wall tells me where to start before I see the roof: the transition where the membrane turns up the masonry. In Edinburg, TX, flashings take a full year of temperature cycles, a long heat-safety season that runs from May through October, and tropical wind and rain on top of that. When one of them fails, the water path is short and the stain appears quickly, which makes flashing the most traceable kind of roof leak and the one most often patched without finding the cause.
I look from the leak backward, find the first detail that is open, and decide whether the repair is a reseal, a rebuilt section or a sign that the whole transition has aged out.
The signs are small. A bead of sealant that has pulled away from the wall, a metal counterflashing that sits proud of the masonry, a membrane edge that has curled off its adhesive or a fastener head that has rusted through its cover. In heat, sealants harden and crack along their length, and a gap the width of a pencil lead can admit a cup of water in a heavy rain. I photograph the gap with a coin or a ruler for scale and note whether the cracks run along the top edge, the bottom edge or the corners.
Corners and returns fail first because they carry movement from two directions.
Wind makes it worse. Gusts that lift an edge also tug on the flashing above it, and a loosened strip that was holding by habit can let go. After a tropical event I check flashings with the same care I give the edge metal, and a wind-damaged edge is the perimeter side of the same inspection.
Water entering behind a wall flashing runs down the back of the wall or along the deck before it shows. The stain may sit several feet from the opening and may arrive hours after the rain stopped. I match the interior marks to the roof plan, then follow the line to the nearest transition. When a stain sits near a skylight or a pipe penetration, I examine the curb or boot first, then work outward.
A moisture survey is helpful here because it shows whether the water spread sideways through the insulation, which would widen the repair boundary beyond the flashing itself.
Interior clues help. Stains that grow after a wind-driven rain but not after a straight-down one point to a vertical surface, because the wind pushed water into the wall detail. Stains that appear after any rain point more toward a horizontal opening. Asking the tenant when the stain grows saves me an hour on the roof.
A new flashing cannot hold on a substrate that is moving or soaked. I check the wall surface where the flashing ends: cracked masonry, loose mortar, deteriorated stucco and failed coping all let water in above the repair. If the reglet or termination bar is corroded, I replace it. If the wall is wet, I report that as a separate condition and recommend the wall repair before the flashing is rebuilt. Without it, the new flashing may last only until the next heavy rain finds the same gap.
A building in Downtown Edinburg that has parapet walls at more than one height needs each height checked on its own.
Metal type matters as well. Galvanized flashing near a salty or damp area can rust through, and aluminum can pit when it touches certain sealants. I note the material, the gauge and the finish, and I match the replacement so two metals are not placed in contact where they would corrode each other.
I press on every termination, probe laps with a blunt tool and tap metal flashings to hear loose sections. I look at fastener spacing and sealant adhesion, at whether counterflashing laps the base flashing and at how the sheet is secured at the top. Sealant alone is a temporary measure. Used over a gap that is moving, it lasts a season, and I say so in the report. Where a detail has been sealed three or four times already, I recommend rebuilding it with fresh materials that bond to the existing sheet.
Rooftop equipment brings its own flashing questions. A unit that has been serviced often wears a path across the membrane, and the technicians' boots may have scuffed the base flashing at the curb. I look at the height of each curb above the roof surface, since a low curb is more likely to leak than a tall one, and I note any that need to be raised in a future project.
A repair runs from sound material to sound material. On a wall, that is a length of base flashing and counterflashing with a secure top termination. On a curb, it is the full perimeter, since a corner repaired alone leaves the other three open to the same movement. I mark the boundary on the roof, photograph the layers and compare it with the readings. If the insulation below the flashing is dry, the repair stays local. If moisture has spread, the boundary grows and the scope is reviewed with the facility director before work continues.
Permitted replacement or energy-upgrade work in the city follows the adopted 2018 International Building Code and Energy Conservation Code, and the written scope notes when those apply.
Flashing repairs are well suited to phased work. A wall length or a single curb can be opened, rebuilt and closed in one shift, which keeps the exposed area small. We confirm the hours, protect entrances and cover equipment below the work, and we plan around the afternoon storms that appear in the Valley's wet months. For owners with similar details across several buildings, such as in Pharr, a standard photo record shows which transitions are failing in each and lets the work be ordered by risk. The related condition on open laps is handled in seam failure repair, and storm-driven cases are covered by storm damage repair.
In the hot months, the work window shortens. Adhesives flash off quickly in direct sun, so crews start early, stage materials in shade and stop bonding when the surface gets too hot to touch. A repair made in a bad window can look fine for a week and fail in a month, so the schedule respects the surface temperature more than the clock.
Because the cause is usually movement or a wet substrate, not the sealant. The deciding factor is what is behind the bead. If the metal is loose, the wall is cracking or the termination is open, sealant only buys a season. Rebuilding the detail addresses the cause.
Often, yes. The two do different jobs and age differently. Counterflashing sheds water off the wall, while base flashing carries it onto the roof. If one is sound, it can stay, but their laps must still align.
Temporary protection can go on when conditions allow, but permanent adhesives and sealants need a dry surface. The repair record notes what was placed temporarily so it can be replaced when the roof is dry.
A single curb or short wall can often be completed in a shift. Longer runs are divided into lengths that can be opened and closed the same day.
Interior stains, the date of each leak and any visible gaps at the roof edge. Even a phone photo from a window helps me choose where to start.