Bests & Worsts Reviews from Amazon

This stuff is amazing: it's like silicone sealant that you apply with a brush. It's slightly thinner than silicone, so that you can easily brush it flat over a large area, but plenty thick enough to stay put when you brush it into cracks, grooves and gaps. I was particularly pleased how well it adhered to the irregular roof surface (asphalt shingles, flashing, and roof cement used for previous patches). Some of the shingles were damp, which didn't affect adhesion at all. The directions say you can apply this when it's raining, but I waited until there had been no rain for about 12 hours. Here's how to do a perfect job: 1. Buy a package of foam brushes like these: 20-Piece Foam Brush Set, 2-Inch. 2 inches is the perfect width: narrow enough not to collapse when you push the sealant hard into cracks, but wide enough to spread nice layers of sealant over big flat surfaces. I used two foam brushes per quart: when one starts to self destruct from brushing into cracks and against rough shingles, toss it and grab a new one. 2. I used a leaf blower to remove all the leaves quickly. 3. For cleaning the roof, you also need a hand brush like this one: Rubbermaid Comm Prod 6342-00-SILV 8" Comm Counter Duster, or one that comes with a brush and dustpan set (you don't need the dustpan.) This is the ultimate tool for cleaning the roof, because it gets rid of all the loose stuff. That's the only cleaning you need to do: get rid of the loose dirt, stone granules and leaves. Make sure to keep the brush away from the sealant! I tried using a broom at first, but it didn't clean into the little cracks, which the whole reason I was up there. This hand brush works better. A paint brush could work as well. 4. USE RUBBER GLOVES! This stuff is SUPER STICKY. It is much tougher to get off your hands than silicon caulk. Also wear old clothes...and resist the urge to wipe your hands on your pants! I brought a rag for wiping. 5. The directions say you can spread a layer 1/8-1/4" thick (3-6 mm). I think if you spread a 1/4" thick layer, you are probably being sloppy and making a mess. 1/16"-1/8" (2-4 mm) is a good guideline. 6. Start at the visible cracks, and jab the sealant into the crack with the brush, then wipe sideways to fill the crack with sealant. It will stay where you put it, but the best way to get a good seal is to embed the sealant deeply into cracks, then brush a nice smooth layer over the top. 7. In some cases, you will be applying over previous sealant like black roofing cement. In my case, there were visible cracks several inches long in the old roofing cement patch. After sealing all the visible cracks (see #6 above), I painted a smooth layer over ALL the visible roofing cement, plus two inches or more beyond. If some of the old roofing cement patch is cracked, the rest will crack within a few years, so seal it now! 8. I had trouble removing the last bit of sealant from the jar. The foam brushes are a bit too short and too weak to scrape from the bottom corners. A paint stirring stick might help here. 9. Bring a trash bag with you onto the roof. As you finish with brushes and jars of sealant and rags and gloves, throw them immediately into the trash bag. Wipe your gloved hands on the inside surface of the bag. Carefully haul the bag straight to the trash can when you are done. You REALLY want to keep this stuff off your clothes, shoes, etc. and because it is clear, it is a bit harder to notice than black roofing cement. 10. I purchased two quart jars to seal around four roof vents. If you are going to the trouble of sealing the roof, buy plenty. I may buy the gallon size next time, but I'll always keep a quart jar around for emergency repairs.