Is the roof painted?

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Is the roof painted?

July 31, 2011, 08:20:54 pm

My roof is covered with black spots (see photo). I tried cleaning it with a blue Scotch Bright; it takes the black off, but leaves a brown spot. Next I tried a Mr Clean Magic Eraser; it cleans the surface pretty good, but doesn't last long. I used up two of them doing about five square feet. A Google search indicates the Magic Eraser might be equivalent to 1,000 to 1,500 grit sandpaper, but those are guesses.
I'm thinking of buying a buffer and using a compound to remove the spots and then a polishing compound to bring out a shine and then polish or wax.
Any suggestions on how to clean this roof? What are these spots?
Thanks.

Re: Is the roof painted?

Reply #1 – July 31, 2011, 08:35:35 pm

Dick,

I had better results with the blue Scotch-Brite pad and fine rubbing compound. But it is a tedious process that will have to be done every so often. And, to be perfectly honest, it is a hard job and at my age I don't like crawling around on my knees unless I am playing with a grandchild or a friend's dog. Like a number of other owners here, I did away with the problem once and for all by having Xtreme Paint & Graphics repaint the roof in October of 2010. I've washed it in a standing position once in the last 10 months and there are no more black spots. Dirt will accumulate on ANY roof, no matter how it is treated, but the paint that James uses does not allow black spots to exist. The cost is around $1100 although it might have gone up in cost somewhat recently.

Re: Is the roof painted?

Reply #2 – July 31, 2011, 08:40:45 pm

That looks like mildew to me. Did you travel bleach?

Re: Is the roof painted?

Reply #3 – July 31, 2011, 10:34:50 pm

Dick,

We used a three step process from a Maguires product that is to be used on gelcoat surfaces of boats. First step is a compound; second a polish; and third a wax. We bought it at a local boat dealer. It worked very well...the roof was as shiny as a side panel... but it was labor intensive. The followup was another Maguire product that was a one step process. We continue to use the one step product on all sides of the coach, BUT we too had a non-slip coating put on the roof and now just rinse off with water and a brush. FOT applied the coating.

Re: Is the roof painted?

Reply #4 – July 31, 2011, 10:39:16 pm

Quote from: Dick S – July 31, 2011, 08:20:54 pm

............................My roof is covered with black spots......................Any suggestions on how to clean this roof? What are these spots?

If it's in an area where mold or mildew might thrive (near AC runoff, an area that stays moist with dew, an area that gets less direct sun, etc.), it looks like a mold or mildew that I have experienced, not as densely populated, but exactly the same appearance and behavior.

I have used a product by Zinsser successfully (JOMAX) on my (unpainted) roof. It is safe to use on painted and unpainted surfaces. It is a mold and mildew killer. It is mixed with water and bleach (3.25 Qts water, 2.25 Cups Bleach, 0.75 Cup JOMAX to make a gallon of solution....I put the solution on with a pump sprayer). Find it at HD, Lowes, ACE, TRU Value Hdwr., Etc. Zinsser - Zinsser Jomax House Cleaner Product Demo

Test a small area.

Spray on, let it sit for five min., hose off, VOILA! It usually requires little to NO scrubbing, and light pressure washing is the best of all.

I also use it on the house siding in NH and FL. If the Mold has caused slight pigmentation staining, and it doesn't immediately disappear, it usually does within a few hours and the product seems to reduce reoccurance dramatically (sometimes two years).

The biggest issue is using the bleach loaded mixture near awning fabric and the waxed areas of the coach. I always extend the awnings, thoroughly saturate them with water inside and outside, and keep everything around the mildewed area well soaked and wet down until after I've used the JOMAX mixture, soaked, pressure washed, and then I thoroughly wash the WHOLE area like in a normal wash-down.

Having a helper watch the sensitive areas and keep them wet down is wise. I've used it where the over-spray and splash goes directly onto sensitive plants and even that wasn't a problem as long as one keeps everything well wet down.

But the best part is how magically the mold disappears! No elbow grease needed!

Neal

Re: Is the roof painted?

Reply #5 – July 31, 2011, 10:49:03 pm

Is the surface fiberglass finished with gel coat? Did the factory apply paint over the gel coat or is that something one does later if desired?

Re: Is the roof painted?

Reply #6 – August 01, 2011, 12:41:38 am

I use TSP it is a mild caustic cleaner that we get in Canada in crystal form but it seems you guys only have it in liquid which is useless. If you can find the crystal just put about 3 tbls spoonfuls in a gallon of warm water and wash the roof. It comes right off then wash it with clear water. Then if your is a gelcoat fibreglass you just polish it with any cheap car polish and that should protect it. I have a large box of it with me all the time and it has been my answer to every cleaning job for many years.

Re: Is the roof painted?

Reply #7 – August 01, 2011, 01:56:05 am

Yep, if you look at the label, it has TSP substitute in small letters on the useless liquid. You can find the crystals if you are a persistent shopper.

Only want to add that TSP works great on most everything from cleaning grease or paint to the washing machine for shop rags but make sure to wear gloves if you apply with a sponge, etc. I forget all the time but pay later.

Re: Is the roof painted?

Reply #8 – August 01, 2011, 05:36:23 am

Dick,

The original roof surface is gel coat. Many of us have had our roofs painted to solve the cleaning problems.

Re: Is the roof painted?

Reply #9 – August 01, 2011, 08:39:15 am

TSP is actually very caustic. The pH of a 1% solution is 12 so if your going to use it try to protect your skin and be sure to rinse thoroughly. It is a good degreaser and should kill mold and mildew. It is hard to find in the US but should be available from an industrial chemical supplier. It is fairly inexpensive but you may have to buy a bulk amount. We used it a lot in the flooring business to prep the concrete before application.

I had my roof painted at Xtreme to avoid mildew and to keep that nasty chalking from running down the side of the coach when it rains or there is heavy dew. Application of the correct paint is certainly the easiest form of prevention.

Re: Is the roof painted?

Reply #10 – August 01, 2011, 10:57:42 am

Dick, If you can pick those black spots off with a fingernail they are most likely a fungus. I had them and it took a rubbing compond and a scotch brite to get them off.
Good luck
Gary B

Re: Is the roof painted?

Reply #11 – August 01, 2011, 02:38:02 pm

I agree it is caustic but I never use it any where near full strength and it works great. I do not use gloves so that tells you the mixture and of course you have to rinse well. It will not harm your paint at all if done this way, and in fact once a year I washed my BMW 735 with it to bring it back to show room shine after polishing. I had been doing that for over 20yrs on them and never a problem.

Re: Is the roof painted?

Reply #12 – August 01, 2011, 08:50:07 pm

You're a brave man John, but after reading many of your posts I think you are more careful and detailed oriented than the average guy. I don't trust myself with TSP. It really is a product that requires rigorous adherence to the mixing instructions.

Re: Is the roof painted?

Reply #13 – August 02, 2011, 05:52:51 am

I remember using TSP to prep a metal garage door for paint. It took the shine off the old paint and etched into it, providing good "tooth" for the new paint. That was a high strength mix; had to wear rubber gloves and goggles.

I found similar spots on my roof (91 U225) in the vicinity of the front A/C. Was able to get most of it off with cleaner. The only gelcoat left on the roof is under the old A/C units, so after a thorough cleaning am going to just paint it. Shopping for ceramic insulating paint right now.

Going to look into Jomax. Thanks for that.

Steve

Re: Is the roof painted?

Reply #14 – August 02, 2011, 11:05:34 pm

Steve, if you can find Zeeospheres by 3M you can add them to any good automotive urethane paint. They are hollow glass spheres and add a lot of insulation and some non-skid to your paint job. The sound very expensive, but a pound bag is similar in size to a pillow case. An ounce should be more than enough for the roof of several coaches. This works great for a cool deck coating around your pool too.

You might also check out PQ Corporation. They used to have a similar product.

Re: Is the roof painted?

Reply #15 – August 03, 2011, 07:15:24 pm

I did a recent roof wash (day before the rest of the coach). A micro-fiber cloth took off the black spots and left a very clean surface. I too have used a three-step process with very good results in the past. I used Mother's automotive pre-wax surface cleaner, sealer, and wax. Lasted well. I have not yet used any marine gelcoat products, but I may next time. Re: TSP - I got my last box of the crystals at a building contractor supply house.

Re: Is the roof painted?

Reply #16 – August 03, 2011, 09:31:01 pm

Quote from: Kent Speers – August 02, 2011, 11:05:34 pm

Steve, if you can find Zeeospheres by 3M you can add them to any good automotive urethane paint. They are hollow glass spheres and add a lot of insulation and some non-skid to your paint job. The sound very expensive, but a pound bag is similar in size to a pillow case. An ounce should be more than enough for the roof of several coaches. This works great for a cool deck coating around your pool too.

You might also check out PQ Corporation. They used to have a similar product.

Thanks kindly Kent. That should save me some time.

I haven't been searching in earnest - what I did come across first time around was mostly latex paint with some fillers. Am hoping to find something I can apply in a fairly simple manner. I do have an HVLP spray system, but would have to do this in my driveway, and that might be a problem.

Steve

Re: Is the roof painted?

Reply #17 – August 04, 2011, 07:26:06 am

Steve, I see no reason that you can't roll the material with a 1/4" roller. My former company makes a product call PM500 Chemical Resistant Urethane. It is a floor coating and designed to be rolled. I'm not sure if they still sell it in small quantities or not.They do not carry the Zeeospheres. If you are interested call 405-755-8448 and ask for Joanne. Tell her I suggested you call her.

No matter what you use, make sure the surface is roughed up and clean as a whistle. Wipe down with solvent right before applying coating.

Re: Is the roof painted?

Reply #18 – August 04, 2011, 08:19:16 am

Thank you Kent.

With no gelcoat, the surface is already somewhat roughed up

. I think cleaning it properly will be the most work. I have a roll of red scotchbrite type material on hand - I use a piece fitted to a random orbital sander to clean and polish the cast iron tops of my machinery. That'll rough up the surface of the fiberglass roof without removing much material.

Will look into all the info you've been kind enough to supply, and come up with a plan. This may take several days to complete, but will be worthwhile. Thanks again.

Steve

Re: Is the roof painted?

Reply #19 – August 04, 2011, 11:54:06 am

clean it with TSP it will be easier and this etches the surface ready to paint or!
(Kent, I will get someone using this stuff sooner or later)

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