Commercial Roof Work
Humidity & Trapped-Moisture Roof Repair with scope notes, photos, and next steps.
A leak you can trace to a torn flashing is the easy kind of wet roof. The kind that costs owners twice is the one with no hole in it at all, where the water came from inside the building, rode up into the roof assembly on the heat and humidity, and condensed in the insulation where nothing on the surface ever shows it getting in. Patch the membrane over that and you have fixed nothing, because the moisture is still being generated from below and the new work will blister and ridge exactly the way the old work did. We chase the cause, not the bubble.
In this climate, the air inside the building is the threat
Few commercial roofing environments in the country are tougher on a roof assembly than ours. The buildings that pay for it are all over Fort Lauderdale: cold-storage and food operations near Port Everglades, busy kitchens along the Las Olas and downtown restaurant rows, laundries and process plants out in the Cypress Creek and State Road 84 flex corridors, and any tightly conditioned space running hard air conditioning against soupy outdoor air. The mechanism is relentless and it runs one direction here. Warm, moisture-laden interior air carries vapor, and that vapor pressure drives it upward through the roof toward the cooler outside. When it reaches a surface inside the assembly that is below the dew point, it condenses into liquid water, and unlike a rain leak it has no entry point to find and seal. It just collects, season after humid season, until the insulation is saturated and the steel deck underneath begins corroding from the top side down where no one can see it.
What humidity damage looks like on the roof
The signs are specific once you have learned to read them. Blistering is the classic one: vapor pressure builds beneath a single-ply membrane and lifts it off the substrate in bubbles that grow and multiply over time. Ridging shows up as long raised welts tracking the insulation board joints, where trapped moisture has wicked into the seams and the board has expanded. Underfoot the field feels spongy and soft wherever the insulation has soaked through and surrendered its compressive strength. And the tapered insulation that was installed to push water toward the drains slumps and crushes under the moisture load, so the designed slope flattens, ponding spreads, and the standing water traps still more heat and still more moisture in a loop that feeds itself. By the time any of this is visible from above, the saturated area is almost always much larger than it looks.
The vapor barrier is usually the real culprit
This is the part most repair crews never check. In a hot, humid climate, the dominant vapor drive runs from the conditioned interior upward and out, which means the vapor retarder belongs low in the assembly, beneath the insulation, where it can stop interior moisture before it ever reaches the cold zone where it would condense. A surprising number of roofs we open up have the retarder in the wrong layer, torn, or missing entirely. When that is the case the assembly is fighting the building physics instead of working with them, and it functions as a moisture trap by design. It is also exactly why recovering over a failed roof without correcting the vapor layer guarantees the same damage reappears inside the new system within a few years. We are not interested in selling you that job twice.
How we diagnose it before we cut anything
You cannot repair what you have not mapped, so we start with an infrared moisture survey. After sundown, when the roof releases the day's stored heat, the saturated insulation stays warmer than the dry insulation around it and reads as discrete hot zones on the thermal image. We confirm those zones with small core cuts that let us see the actual insulation condition, the state of the deck below it, and crucially whether a vapor retarder exists and where it sits in the stack. On any sizeable Fort Lauderdale roof that has not had a documented moisture survey in the last three years, we recommend running one as the first step of any assessment. Wet insulation caught early is a contained repair. Wet insulation caught after it has corroded through the deck is a tear-off, and the difference between those two outcomes is usually a matter of timing.
Repair or replace, decided by the survey, not the salesman
Once the moisture map exists, the decision gets honest. If the wet insulation sits in defined zones with sound, dry material around them, we cut those areas out, replace the saturated board with new dry insulation matched in thickness, restore the membrane over the repair, and reset the edge metal and flashings in the affected area. Where the survey shows wet insulation across roughly a quarter or more of the field, or where the deck has corroded enough to threaten the structure, repair stops being economical and full replacement with corrected vapor management becomes the straight answer. We hand you the survey report and a side-by-side of the repair option against the replacement option, and the call is yours, made on real data instead of a guess.
The repair itself, built so it actually lasts
When we cut out a wet zone we do not simply drop new board into the opening and weld over it. We dry or remove the surrounding substrate back to genuinely sound material, confirm the deck beneath is solid steel rather than rust, and where the original assembly lacked proper vapor control we correct it within the repair instead of rebuilding the same trap at a smaller scale. The replacement insulation is matched in thickness so the slope to drain is preserved, the membrane is tied back into the existing field with a fully welded or fully adhered detail rather than a smear of mastic that lets go at the edge, and the perimeter metal and flashings in the work area are reset properly. The goal is a repair that disappears into the roof and carries the same remaining service life as the sound material around it, not a visible patch that fails at its own seams in two summers and brings us back.
Why moving on it early pays off
- Wet insulation has almost no thermal value, so a saturated roof quietly inflates the cooling bill on every hot day, which in this climate is most of them.
- Steel deck corrosion accelerates under constant moisture, and a corroded deck turns a roofing repair into a structural one with a much bigger price tag.
- A roof reading fifteen percent wet today, left alone for two more seasons, can read forty or fifty percent at the next survey, pushing a manageable repair into a full replacement.
- Correcting the vapor problem now means we fix the cause one time, rather than you paying to recreate it inside a brand-new assembly.
If your building is showing blisters, soft spots, ridged seams, or a cooling bill that keeps climbing with no clear reason, the roof may be holding water you will never see from a ladder. Call us for an infrared survey and let us tell you whether you have a repair or a replacement, before the roof makes that decision for you.