Cleaning EPDM and Other Single-Ply Roofs
In the early days of EPDM some manufacturers used unleaded gasoline as seam cleaner. It was affordable and worked fine to remove the talc on the surface of the "New" EPDM. Proper cleaning of the seams was always a workmanship issue and a major reason for seam failure. The same cleaning protocols and issues that apply to EPDM seams, apply to epdm repairs. Over the years, I have found that "hot" solvents like lacquer thinner and acetone, used properly are better cleaners. All cleaner/solvents, can "eat up" EPS insulation, so it's best to know what is under the EPDM. This is not typically a big problem for seam repairs, but you should be aware of it.
"Plastic" roofs, like Hypalon, PVC, and TPO can be cleaned the same way as EPDM, but for repairs I prefer to "score" or sand the surface to remove any oxidation. I use a fine grit sanding sponge, or a scotch-brite pad, or equal. Then I wipe off the dust I've created with a rag soaked with solvent, or even water.
Tapes need pressure from your hand, or a steel roller to be applied correctly. Low density insulation because it has a tendency to be "soft" also makes a poor rolling surface, which may be the reason the seams failed in the first place. EternaBond® repair tapes all have primer already infused in the MicroSealant® adhesive to reduce these problems. They, too, are pressure activated. In the event the insulation is too soft to get a decent amount of pressure, EternaBond® offers a primer called EternaPrime®. Painting or spraying EternaPrime® on the repair surface and allowing it to dry (+/- 1/2 hour) infuses the MicroSealant® resin into the membrane surface. The result has the same effect of putting a piece of tape against a piece of tape. Another trick if the roof is to soft, is to warm up the EternaBond®. There are several methods, but I find filling a bucket with hot water and dropping the roll of tape in it for a few minutes does a great job. I wouldn't try this with other tapes, but it works will with EternaBond®.
Cleaning EPDM membrane that has been covered with ballast can be a royal pain. The only good way to move heavy ballast like stone is with a shovel. Shovels can cause serious damage to the membrane when windrowing ballast, so the technician has to really pay attention. Expect dirt and mud, which can be several inches thick in valleys and around drains. Heavy brushing and even power washing may be required to get rid of the big stuff. The lighter dirt can be coalesced (fused together and to the roof) using EternaPrime®.
Manufacturers cannot stress clean seams enough. The question is "what is the best way to go"? My opinion is elbow grease, a good "hot" solvent like acetone, lacquer thinner, or a commercially available cleaner made specifically for the roof type. Of course, use proper caution when using a solvent. They are flammable, can burn skin and eyes and the fumes can be toxic. EternaBond® is a very permanent and forgiving repair system because the MicroSealant® adhesive is so aggressive. EternaPrime® just makes an easy, long lasting repair even more fool-proof.
As appearing in Roofing/Siding/Insulation (RSI), Feb 1, 2005.