I think it chemically prepped the black areas, but it left a slight white film. Maybe it's supposed too. The instructions say to spray off with pressure washer until no more bubbles. I used a soft brush on a medium handle and a spray hose, and it took literally about 10 passes to get it to stop making bubbles when spraying off. A lot of work!The first couple passes I used a regular restaurant detergent similar to simple green. I used this product full strength on part, and then just spread it around with the brush on top of already wet surface for the rest. I don't think it needs to be full strength, because it acted the same at least from a macro level and it doesn't look like it is highly pH dependent, though the msds did say an acid in it. It stinks quite a bit and so it seems to be some chemical activation.Anyway, it takes forever to get the bubbles to stop, but I wanted to do it 'right'. It definitely cleans it better compared to scrubbing with rubbing alcohol, so it was doing something. I wouldn't recommend skipping it before any of the acrylic based roof coatings. I've heard of them peeling up without good prep from an honest dealer repair shop. There are a couple of actual 'rubber roof coatings' that are made of rubber, not just acrylic to coat a rubber roof (see the ambiguity of that name?). They are more expensive, but could probably save from a full roof redo. Don't use the silicone coatings like the Henrys Tropicool at home depot, because nothing will ever bond to it without some major chemical activation.Time will tell. I'll try to update if I see any major differences in the test areas after 5 or 10 years if possible.

Worked well, made roof coating adhere well

Product was easy to use however it didn't turn our roof white. The instructions say that it should so we were concerned that it hadn't worked. We were able to get ahold of dicor and they confirmed it doesn't always turn your roof white after application and scrub/rinse off.

Easy to apply and rinse off. This is the first part of a multi-part system so make sure to getting the coating itself. This is just the cleaner/surface preparation.

Easyvto use but a mess to clean the RV. Tried to protect the rv with plastic...ya no. Best to have someone rinsing off the sides at the same time someone is rinsing off the top. When it dries it takes some elbow grease to clean.

Great product!

Cleans like nobody's business

This stuff really cleaned my roof. Also it made the rubber surface slightly tacky which really improves the bond with the top coat of EDPM rubber.I didn't put the plastic wrap on my RV. Lots of granny white partials but washed off easily.

Ready to use. BUT must use with the 2 step.

Definitely use this before the rubber coating. Cover the sides to keep this off the RV finish. Doesn't immediately stain. I washed it off quickly with no residual damage.

Great cleaner for your camper roof. Easy to rinse off the roof.

Use a medium course brush or broom with narrow head and long handle. That will scrub the oxidation and remove any other crud. A coarse bristle will risk damage, and a large head will snag on roof equipment and fixtures. Two bottles allowed two passes on my 34' camper roof. Removed about 80 of oxidation using a car style wash brush (yes, too soft but head size and handle length were excellent) with extension handle. Poured cleaner right out of the bottle. Wished it were more milk-like.

MY CAMPER ROOF WAS 128 SQ. FT. I BOUGHT 2 GALLONS DICOR ROOF COATING AND 1 QT. CLEANER/ACTIVATOR. WRAPPED THE CAMPER SHELL IN PLASTIC SHEETING. FIRST LIGHT I POURED OUT THE CLEANER/ACTIVATOR AND LET IT DRY. PRESSURE WASHED THE CLEANER OFF AND LET DRY (SCORED A PRESSURE WASHER FOR BIRTHDAY). APPLIED THE FIRST COAT OF COATING AND LET DRY, ABOUT 20 MIN. APPLIED THE SECOND COAT AND LET DRY. HAD PLENTY LEFT SO I APPLIED THE THIRD COAT. THIS STUFF SO FAR IS PROVING TO BE AN EXCELLENT PRODUCT. JUST FOLLOW THE DIRECTIONS AND RESULTS WILL BE REWARDING. BEEN 2 MONTHS SO I HOPE IT WILL HOLD UP. TIME WILL TELL.

Excellent product, read the directions, weather conditions must be just right for this project if you do it outdoors.

We used this on our rv roof no leaks after using this and the paint worked great very happy with results

Worked as described.Followed the directions and had no problems.

Purchased to repair the roof on a RV

Cleaned and prepped for my fresh roof coating

It was a pain having to tape plastic all the way around the RV, I just used the cheapest 100' rolls of 12' plastic sheeting I could find and taped it on with yellow painters tape. It cleaned the roof pretty good, I just used a regular little hand spray bottle, if I did it again I'd buy a cheap garden sprayer just because your hand will cramp up spraying it on with a bottle sprayer.4-5 months later the pavement around my RV is still stained a dull white from after rinsing it, but it didn't kill the grass.If it wasn't for having to put the plastic up this wouldn't have been a very difficult project.Also, I should have bought more, I ended up actually having to buy more and do my slide outs later. I read numerous reviews of people saying they didn't need the recommended amount, so I bought based on what other people were saying, that was a mistake.

I applied Step 1 to my RV roof, let set a bit, then mildly scrubbed with bristle brush and rinsed. After it dried, I used the blue painters tape masking off the areas to be avoided and proceeded to step 2. I assume it works as an activator/adhesive prep for Step 2. The whole process isnt hard , its just time consuming. hot work on the roof in the sun and messy. But it is rewarding when you get done.