The right conditions for coating

CCS Influencer Lisa Irby says roof condition is the deciding factor when it comes to coating. 

A roof should only be coated if it’s in condition to coat. If a flat roof has over 25% moisture, I would recommend replace/recover verses coat. The reason I suggest this is because repairs with a coating system can be more expensive than a single ply system on a flat roof if it’s a recover. As far as a metal roof the repairs can sometimes make the price to coat more than a TPO flute filled system. I always suggest if there are any signs of rust to make sure to rust prime to roof prior to installing a coating system.

I have seen failure if the incorrect application is installed on flat roofs. A flat roof should have a solvent based system or a hybrid system of acrylic with a solvent (urethane or silicone) topcoat. It’s most common to install acrylic on metal roofs but depending on the area you’re in or the time of the year, you can install a silicone system, but you must be careful with that due to silicone being slippery. If you install silicone I highly recommend you install granules along the perimeter.

The best systems for coating are ones without a lot of leaks, not in failure mode and the surfacing is not starting to degenerate. If a roof is properly maintained there is no reason not to coat. The same applies for a metal roof, if the screws have been maintained and all the penetrations. The skylights need to be removed, and panels installed or safety cages over the new skylights for safety reasons.You also must be careful with the original application of a metal roof. If it’s a seamed panel and it’s fastened incorrectly it can sheer or destroy the coating system. It’s very important to know if the roof leaks and to walk the roof to check the laps for said damage.