Commercial Roofing
A dark membrane that has chalked and blistered in a single season, with air conditioning that never catches up by mid-afternoon, is a roof soaking up more heat than the building can shed. Half of every year in Edinburg, TX falls inside the weather service's May-to-October heat-safety window, so a roof carries sustained solar load for months at a stretch, and the surface on it decides how much of that heat reaches the space below.
A cool roof sends more sunlight back to the sky and gives up more of the heat it does absorb. It does not fix a leaking roof or replace insulation, so the first check is whether the roof beneath can carry a reflective finish at all: dry insulation, sound seams and flashings that still hold.
Sunlight lands on a roof and is either reflected, turned into heat at the surface or conducted into the assembly. A dark membrane turns most of it into heat, and the surface can run far hotter than the air above it. That temperature works on every part of the roof. Seams soften and shift, sealants dry out, flashings pull at their edges, and the membrane itself loses plasticizer or elasticity sooner than it would in shade.
Reflectance and thermal emittance are the two rated properties that describe the response, and both are published for tested products. We read the rated figures for the system we are considering instead of judging by color, because a light finish with poor emittance can hold more heat than expected. Those figures also fall as dust and algae collect, so the plan includes cleaning. A heat and UV damage repair often precedes a reflective finish, since a cracked or loose area will not stay bonded under a coating.
Several systems can be made reflective. White TPO and PVC single-ply membranes arrive reflective from the factory and suit a full replacement. A sound existing roof can instead be coated with a liquid, acrylic or silicone, that cures into a continuous film over the old surface. Metal roofs accept reflective coatings and finishes, and certain modified bitumen cap sheets are made with a lighter granule.
The choice follows the condition of what is there. A coating over wet insulation seals the water in, so we confirm the substrate is dry with an infrared moisture survey and a few cuts. A roof that ponds is a better candidate for silicone than acrylic, and a roof with failing seams may be better replaced than coated. We lay out the options with what each one needs from the roof beneath. The written scope names the surface, the number of coats or the sheet thickness, the treatment of seams, penetrations and edges, and the photo record that will show the finished work, so the owner can compare options line by line.
Hurricane readiness runs June to October and flood preparedness all year, the weather service says, and Hanna's July 2020 visit left wind and flooding in Edinburg. A reflective roof has to meet those events as any other roof does. Edges must be secured, seams bonded, drains clear and flashings sound, and a cool finish adds nothing if the edge lifts in a gust.
Coatings add a question about cure. A fresh film that sees rain before it has cured can wash off, so installation is planned around the forecast and finished in sections that can be completed before an afternoon storm. For membranes, the attachment pattern around the perimeter and corners is checked against the wind exposure of the building. After a tropical event we inspect for lifted edges and open seams before concluding that the surface is intact, and we photograph what we find for the roof record.
Edinburg's adopted code list names the 2018 IBC and the 2018 IECC. A roof that is replaced or heavily altered can trigger requirements for insulation, air barriers and surface properties, and how much applies follows the extent of the work. A coating alone may not satisfy insulation rules where a roof is being rebuilt.
We read the adopted code and the permit requirements at the start of a job and put what applies into the scope before pricing. Plenty of projects end up as a roof insulation and cover board decision as much as a membrane one, since extra insulation raises curb and flashing heights and changes drainage. Putting those items in the scope early keeps a permit review from reopening the plan.
A white surface loses reflectance slowly. Dust, pollen, algae and mineral deposits from ponded water darken it, and a ring at each low spot holds heat. Where a drain is slow, the dirt line shows exactly where water has been standing, which makes the stain a free drainage survey. A wash at the end of the dry stretch brings back much of the reflectance without wearing the surface, provided the pressure is moderate and the laps have been checked first. High pressure drives water under laps and into seams.
Coated roofs need a different check. A coating is a thin film, and it wears first at foot-traffic routes, around curbs and where water stands. A short annual look, added to a preventive maintenance round, catches thin spots while a recoat is still a small item. The roof record carries the product type, the date and the thickness readings, so the next owner knows what is on the roof.
The local economic development group identifies distribution and warehousing activity, with healthcare, higher education, government, food processing and manufacturing also in the employment mix. Buildings that hold conditioned space, cold product or heat-sensitive operations feel a hot roof sooner than open storage does, and the cooling load shows up in the utility bill. Whichever use sits under the roof, the work begins with a walk across it.
For owners in Edinburg, McAllen and Pharr, we compare a reflective replacement with a coating on the existing roof by condition, remaining life and budget. The comparison sets the cost of each path next to the heat benefit it brings, so the decision rests on the roof's evidence and not on color alone.
Often, though the size of the saving depends on insulation, equipment and how much of the load comes through the roof. We describe the likely effect for the building in front of us and do not quote a fixed figure.
Yes, when the membrane is sound and the insulation below is dry. A scan and a few cuts show moisture, and a patch test shows whether the coating bonds.
It falls as dirt and algae collect, and the rate varies with the site. Rated aged values from the manufacturer are a better guide than the new-product number, and cleaning slows the decline.
No. Reflectance and emittance are rated numbers, and the system must also suit the roof's condition, drainage and attachment. We compare rated values and check the roof before choosing.
We plan sections that can be finished before the usual afternoon weather and watch the forecast. A film that gets wet before it cures is inspected and redone where it has washed or blistered.