Cleaning a PVC membrane on a commercial roofing system provides a lot of benefits. But how do you clean a roof? How often should you have it done? And what should you do to avoid damaging the membrane, roofing system and environment?
Keeping your roof looking great can also be important — especially when it’s the “centre” of attention and visible from the ground. These photos of a Sentry Roof crew as they clean a PVC commercial roof we constructed for the Riverdale Town Centre demonstrate how it’s done properly. This particular roof is in an environment with a lot of airborne particles so the roof had gotten noticeably dirty and, because of the roof’s slope and lack of edges, we needed to put in safety extensions and anchors to properly tie off our crew during the cleaning, as you can see. You’ll also notice this PVC roof has standing seams — decorative parallel lines that follow the line of the roof and call attention to it — which adds an extra element to be careful of when cleaning.
It’s best to have your roof cleaned by trained professionals who understand roofing systems and all the related caveats. If you can have the company that installed the roof do the cleaning as well, all the better — they understand your roof best and will have added pride in their work (not to mention skin in the game).
Why you should keep your PVC roof clean
- Extends the life of the roof
- Keeps the roof at most reflective, which lower its temperature and conserves energy
- Keeps algae growth and pests at bay
- Keeps the membrane free from contaminants that might reduce performance and longevity
- Allows your maintenance professionals to spot potential problem areas before they get worse
What the crew needs to be careful of
- Not using high pressure — 1,500-2,000psi max (most commercial pressure washers are around 3,500psi)
- Not slipping — wet membranes are slippery
- Not walking on the cleansing solution — rinse it away first
- Not damaging the exterior facade with the cleansing solution — test it first
- Not allowing water under pressure to enter the roofing system — protect curbs and flashings
- Not contaminating plants or groundwater with runoff — comply with water run-off requirements
How to clean your PVC roof without damaging it or the environment
- Rinse off the top layer of dirt using a low-pressure power washer at 2,000 psi or lower
- Use the right cleanser
- Water only
- A non-sudsing, non-abrasive, powdered cleanser
- An environmentally friendly cleaning solution made specifically for PVC roofs
- A solution made from a mild, non-abrasive household detergent and water
- Use one of the following tools to gently clean the surface
- A rotary surface cleaner attachment on the pressure washer (see photos)
- A natural-fiber cloth or soft-bristle brush
- A floor buffer run on a low speed using a non-abrasive pad
- Do NOT use the pressure-washer wand to do the washing — too much concentrated pressure
- Rinse the roof completely with the low-pressure power washer to remove the cleaning solution
- Inspect the membrane for any damage from the cleaning process
How frequently you should clean your PVC roof
If you have a maintenance program to remove debris from your roof on a regular basis and if you clean your roof each year, you might not need to use any cleansing agents at all — water alone could be enough to get all the benefits of a clean PVC roof. If your roof is susceptible to dirt and dust accumulation or severe environmental contaminants because of its location, on the other hand, you may need to use a cleanser every time or clean more often with water alone.
Roof slope and drainage also impact how quickly a roof gets dirty, how often you need to clean it, and what you use to clean a PVC commercial roof.
If you have a PVC roof in the metro Atlanta area (or a TPO roof, which also needs periodic cleaning) that hasn’t been cleaned in awhile — or maybe ever? — feel free to give us a call so we can take a look and make a recommendation. We’ve seen first-hand that clean PVC roofs last longer. Most importantly from a roof management perspective, if your roof is clean it’s a lot easier for us to spot problem areas early and provide the kind of solid advice and services you need to protect your investment. Sentry Roof installs PVC roof membranes manufactured by GAF, Johns Manville, Duro-Last, and, as pictured here with the Riverdale Town Centre, Sika Sarnafil, the premium brand of PVC. All of the brands we work with have excellent track records.