Commercial Roofing
Picture a roof with eleven pipe penetrations, three skylights, two curbs and a stair bulkhead. A sheet membrane has to be cut, fitted and welded around every one of them, and each weld is a place for water to try. Spray foam takes a different route: it is sprayed as liquid, expands and sets hard around whatever is in its way, and leaves a continuous insulated surface with no seams to open.
Spray polyurethane foam, SPF, suits some roofs in Edinburg, TX very well, where a long heat season rewards insulation and tropical rain punishes every joint. It also asks more of the weather and the crew than most systems. We spray it when the roof qualifies and say plainly when it does not. The first question is whether the surface underneath is dry.
The foam goes on in layers, called lifts, and a probe checks thickness before the next lift. When it cures it is a firm, lightweight board. Left bare, sunlight would chew through it quickly, so a coating covers it: silicone or acrylic, sometimes with granules added where people walk.
Together the foam and coating form one continuous skin. The foam insulates and the coating waterproofs and reflects, and the coating is the part that wears. It needs inspection every year and a recoat on a schedule, while the foam beneath can outlast several coatings as long as nothing lets water in. Of the two, silicone forgives ponding better, and an acrylic is easier to renew on a roof that drains well.
Foam is picky. A damp surface ruins adhesion, a gusty morning scatters overspray onto cars and glass, and a surface that is too hot or too cool cures into a rough, weak layer. The manufacturer gives a window for air and surface temperature, wind and humidity, and the crew works inside it or does not spray.
The Valley adds humidity and morning dew, so a moisture meter reading on the substrate comes before the first pass each day. With heat-safety running May to October and hurricane readiness June to October on the weather service's calendar, calm, dry mornings are the practical spraying hours. We check wind through the day, mask what is nearby and stop when the conditions change, since a failed pass costs more than a postponed one. Pressure and temperature readings are checked and logged between lifts, because a mid-lift fault leaves an uneven layer that has to be cut out.
Closed-cell foam is insulation bonded straight to the roof surface. There is no air gap behind it for hot air to circulate, and in a cooling-dominated climate that matters: the roof passes less heat to the space below, and humid air does not find a cool surface to condense on. A roof that is rebuilt or substantially altered is reviewed against Edinburg's adopted 2018 IBC and IECC.
We work out how much foam reaches the target insulation value, then confirm that foam, substrate and coating are an approved combination. Fire behavior is part of that: uncovered foam burns, so the building code calls for particular coverings or thermal barriers, and the job plan follows the design. Where the old roof has little insulation, a roof insulation and cover board comparison belongs in the same discussion.
It can build a slope. By thickening the foam in some places and thinning it in others, an installer makes a taper that moves water to the drains on a deck that has sagged or never had much fall. That is a quiet benefit on older roofs that pond. It only works if the framing can take the foam plus the weight of water in a downpour, and when the drains sit low enough to catch what arrives.
Foam that stays wet for long stretches can break down, and Hanna's July 2020 wind and flooding in Edinburg is why we do not treat ponding lightly. We shoot elevations with a level, plan the taper, and add a drain where the roof has none. A separate ponding water correction applies to other roof types the same way.
Low spots also say something about the deck. A dip that follows a line of fasteners suggests a loose or corroded deck panel, while a dip beside a drain suggests the drain sits proud of the roof. We note both, since foam over a loose panel cracks along the panel edge and foam over a high drain still ponds around it.
Foam looks tough and is not. Its coated surface dents and punctures more easily than a sheet membrane. Spring 2012 brought large hail to the four-city McAllen-Edinburg-Mission-Pharr metro, and hail, dropped tools and the feet of new equipment can all break the coating. Birds peck at it, and sun destroys any bare patch within a season.
Early repairs are cheap: clean, patch the foam, recoat. Late repairs are not. We keep foot traffic on marked walk pads along service routes, keep grease and solvents away from the coating, and warn equipment installers about piercing the roof. A foam roof's commercial roof repair visit begins with a coating survey of every dent, scuff and thin area, and each item is fixed before water reaches the foam.
The City of Hidalgo Economic Development Corporation promotes business property and local business development, including redevelopment in Historical Old Hidalgo. Where a redevelopment area has a roof crowded with equipment and small details, foam's joint-free coverage helps if the substrate suits it. The weather service documents the 2012 hail across the McAllen metro, a reminder that a foam coating wants periodic checks.
We work in Hidalgo, McAllen and Edinburg, lining foam up against modified bitumen and single-ply options roof by roof. The cost drivers are straightforward: foam thickness, number of coating coats, masking and protection, and how much the old surface needs. Roofs full of obstacles lean toward foam, since sheet systems need hand-cut flashing at each one, and wide open roofs with little on them often lean toward a membrane.
The written scope states the thickness, the coating and its coats, and the photographs that will document each lift, so the owner can set it beside a membrane quote line for line and see where the two scopes differ, including what each assumes about the old roof underneath.
When the existing roof tests dry, clean and well attached, yes. A scan and a few cores show whether it qualifies, and soaked insulation has to come out first.
It wears with sun, traffic and ponding. We inspect it every year and set the recoat date from what we find, not from a fixed calendar.
Fumes are released during application, so intakes get covered or shut off during the work and the cure. We set the schedule with the property manager.
A dent that leaves the coating whole is cosmetic. A break exposes foam to sun and water, so it is cleaned, patched and recoated promptly.
Within limits, since foam can be tapered toward the drains. A roof with chronic ponds also gets a hard look at drain location and coating choice.