Commercial Flat Roofing Systems

We install and repair TPO, PVC, modified bitumen, metal and roof coating systems. TPO and modified bitumen are the most common on San Antonio commercial buildings. The right system depends on the roof's slope and drainage, foot traffic from rooftop equipment, what gets vented onto the roof, and how long the owner plans to hold the property. The written bid explains the options and the warranty each one carries.

We trace it on the roof, not from the ceiling stain. On a low-slope roof, water often gets in at a seam, flashing, penetration or drain some distance from where it shows up inside. We check the membrane, seams, curbs and drains upslope of the leak, photograph what we find, and take a core sample if we suspect wet insulation. The repair then fixes the cause, and you get photos of the problem and the finished work.

Often, yes. Building code allows a new roof over one existing roof as long as the existing roof is dry, sound and well attached. If there are already two roofs, or the insulation underneath is wet, the old roofing has to come off down to the deck. We take core samples to check before we recommend a recover. When a roof qualifies, recovering can save up to 30% compared with a full tear-off.

TPO (thermoplastic polyolefin) is a single-ply membrane, usually white, used on flat and low-slope commercial roofs. Its seams are heat-welded into one continuous sheet, and the reflective surface helps with San Antonio heat. It's mechanically fastened or fully adhered over insulation, in thicknesses such as 45, 60 or 80 mil depending on the building and the warranty.

Both are white, heat-welded single-ply membranes. PVC holds up better to grease and chemicals, which makes it the usual choice for restaurants and buildings with kitchen exhaust on the roof. TPO typically costs less and performs well on most other commercial buildings. We recommend one or the other based on what the roof is exposed to.

Water that sits on a flat roof for more than a couple of days after rain points to a drainage problem. Depending on the cause, the fix is clearing or lowering drains and scuppers, adding crickets to move water around equipment, or adding tapered insulation to build slope into the roof during a repair or replacement. Ponding speeds up wear on most membranes, so it's worth correcting rather than patching around.

There isn't one best system. TPO is the most common choice in San Antonio for its heat reflection and welded seams. Modified bitumen stands up well to foot traffic and works over many existing roofs. PVC suits roofs exposed to grease or chemicals, and a coating can extend the life of a roof that is still dry and sound. We recommend based on your roof's condition, drainage and how the building is used.