Re: How do I clean my shingle roof?

a few thoughts....

why an elastromeric roof paint? if your ponding water on your roof, most people believe a coating with elastromeric will solve water issues. It's not true. While elastromeric roof paint is thick, it's not meant to prevent water leaks or waterproofing at all. It does offer a great RF value (reflective) and is thick enough to help certain surfaces, but mostly on a flat roof it's a no-no. You would be better off making sure your roof is pitched to shed water and spend money on replacing the shingle roll. (fyi - there are certain roofs elastromeric coatings are good for(ie gravel roofs))

To answer your question, there are several DIY brand chemicals that are sold at your local hardware stores to "clean your shingle roof". While I've never used them, I haven't heard good things about any of them. For the most part, it takes too much time and too much product to be effective.

some thoughts:

- NEVER pressure clean a roof! NEVER!!! There are so called "professionals" that make a living from power washing roofs, but they shouldn't be blamed for doing what everyone else does. I made a career out of working with Local/State/Federal clients as well as Regional and National chains on cleaning their roofs, and there is a better way! A cost effective way would be to use chlorine (bought from a pool supply company). We have done extensive testing on surfaces and had independent labs test samples of mold on roofs, and the best chemical to use remains chlorine. If you're going to tackle your flat roof yourself, get a garden sprayer and mix the liquid chlorine 50/50 with water. Spray the mixture on the shingle and wait until the mold to turn gray to light brown. Rinse with a garden hose - repeat as necessary. If needed, one national cleaning company (U-Save® travels and consults in shingle roof cleanings 800-494-7470). As for the nay sayers and their way of doing things, here's what we found:

1) pressure cleaning a shingle roof will remove granules - will not kill the mold - and will push/separate asphalt shingle apart while letting moisture get where it's not supposed to be.

2) power washing tile roofs will wear the substrate and etch the tile. If not a color-thru tile, it's likely a slurry coat. Slurry coats can be damaged with power washing. Color thru tiles typically are weakened from the extra dye used in the casting and power washing a tile roof could lead to damaging the tiles. Note- water will also be pushed into areas that typically doesn't get water - which can lead to underlayment failures.

3)pressure washing a shake shingle roof will wear the shake and create huge problems. Once a shake shingle roof has gone to "gray" your best option would be to chemically clean the shake and apply a clear or tinted stain. Those shake roofs that "look" fine after power washing are from stripping the shake past its normal aged/grayed (if not continuously treated) exterior to a thinner shake shingle - leaving several problems that might not be noticed immediately.

4)There are NO special chemicals you can put on a roof to make it stay cleaner longer! Mold does not grow on the surface of the roof but on the particulates that land on your roof (ie: pollen, minute clippings, ect) - so DON'T get taken by snake oil companies promising years of maitnance free work!

Just remember..... Shingle roofs can be cleaned, but only with a chemical and a water hose!

Best of luck!