This post was written by Miina De Lara and reviewed for accuracy by roofing expert John Skoog.
As roofers who do a lot of commercial flat roofs, we at Sunvek WA often hear from clients looking for leak solutions for aging Thermoplastic Polyolefin (TPO) roofs.
TPO roofs are comprised of a thick tarpaulin-type material that comes in rolls. These rolls are laid out parallel to each other and overlapped to create a seam that is sealed with a heat gun. When it comes to a large commercial roof, this means that there are often thousands of linear feet of seams across an entire roof.
These seams are affected by heat, and as the building naturally expands and contracts with ambient temperatures fluctuations, these seams can begin to loosen. The entire TPO roof simultaneously begins to slowly deteriorate from photo-oxidation. This photo-oxidation happens across the entire roof and produces a powdery top layer comprised of the waterproof top layer of the TPO. Each year the roof becomes less and less effective at shedding water as it slowly disintegrates into powder. In addition to gradual deterioration from photo-oxidation across the entire roof, there are smaller local areas that experience accelerated deterioration.
Accelerated TPO Deterioration Causes
UV-Related deterioration. This often occurs on southern exposures at the base of rooftop equipment due to intense sun exposure year-round.
Debris-related deterioration. This often occurs where sand, gravel, dirt, and other debris builds up on the roof and abrade the surface of the TPO.
Water-related deterioration. This often occurs where divots in the roof collect rain water and the standing water accelerates the deterioration of the TPO.
Click on each of the photos to see a description of which type of deterioration is displayed.
Deteriorating TPO offers the opportunity for water to penetrate the roof and become trapped underneath the TPO or leak into the building. Trapped moisture spreads out across a large area, rots the roof, and increases repair costs. Leaks can damage costly equipment or merchandise within the building in addition to damaging the structure itself.
Deteriorated or leaky TPO areas are often patched with TPO by TPO contractors. These patches can serve their purpose, but are also subject to deterioration, and we often see the adhesives deteriorate before the patches do. In some cases, TPO roofs result in patches upon patches, offering multiple points where the adhesives can fail and moisture can damage the building. The photo below offers a prime example of this. As you can see, one area in the lower center of the photo has been patched several times. See if you can count the layers!
When it comes time to fix a TPO roof, many of our clients shy away from replacing the TPO with more TPO, or a new roof, and instead opt for a restoration service. Restoration involves cleaning, preparing, and re-sealing the surface of the TPO with silicone coating to extend the life of the existing roof. Silicone coating adheres fully to a properly prepared TPO surface and avoids the cost of tearing off and replacing the roof. Silicone roof coatings provide a thick and durable top layer that protects the roof and offers superior water shedding, UV resistance, and heat reflection.
Sunvek WA specializes in restoring TPO with silicone coating. We prepare a TPO roof for a silicone restoration by pressure washing the roof. This removes dust and photo-oxidation powder. Cleaning ensures that the silicone adheres fully to the surface. If there are any holes or fully deteriorated areas, we patch the area with fabric mesh and silicone. We apply an initial layer of silicone to all of the seams to completely seal them before we coating the entire roof. This means that we double coat all of the seams, holes, and problem areas.
Our roof coating is applied first with a professional-grade spray gun and then “backrolled” with a paint roller. Backrolling is where the roofing assistant uses a large paint roller and rolls the coating out. This ensures that the coating adheres fully to the TPO, that it is applied evenly, and that it fills any pinholes in the roof. We spray the coating up around any rooftop equipment, vents, scuppers, flashing, stacks, and other structures on the roof. The layer of coating covers any existing seams or patches and fully seals the roof. This ensures 100% coverage of the entire roof in one seamless layer.
Once a roof is finished it must cure for at least 24 hours before it is walked on. Once the roof has cured, one of our team members walks the roof again, and double checks to ensure a complete seal. Any problem areas are double-checked, and if any more silicone is needed it is applied where appropriate. Just like that your TPO roof has been restored and can continue to serve you for years to come!
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