What is the best product to clean RV roof?

Dear Dave,
What is the best product to clean the roof on my RV? —From Just About Everyone!

Hey, (almost) Everyone,
I have gotten this question from so many readers and seminar attendees for many years and I just posted a few days ago my “go to” cleaner has always been Dawn dish soap. And now this old dog is learning new tricks! In my recent post, I discussed how Dawn dish soap breaks down ceramic coating and wax and the Meguiar’s product is the best. So why can’t it be used on the roof where there is no ceramic or wax?

First, it depends on the type of roof material you have such as aluminum, fiberglass, or one of the several rubber membranes. Crane Composites, the manufacturer of the fiberglass panels known as Filon and Noble, recommends using a mild liquid detergent, of which Dawn would be one of the best.

There are several manufacturers such as Winnebago Industries and others that use fiberglass for the outer roof material. It would not have a ceramic coating but might have a wax if the owner was very ambitious! This fiberglass sheet has an exterior layer of what is called Gel Coat, which gives it a shine. Typically the panels used on the roof have a very thin layer of Gel Coat and some even use the orange peel product that has several small bumps in the finish. This strengthens the material, especially at the sides that make a 4” bend.

This panel has a very dull finish versus the sidewall material that has an automotive shine and more layers of the clear Gel Coat material. Dawn Dish Soap will not deteriorate the Gel Coat, so it can be used on the fiberglass roof material. Just make sure you wet the sidewalls repeatedly when washing if you have wax or a ceramic finish applied, and the suds will not affect that. It also helps to prevent chalking or etching when the soap and dirt runs down the side and dries before being washed off.

What about rubber membranes

I remember back in the late 1980s when manufacturers started using EPDM on roofs as the aluminum used previously became more expensive, created horrible black streaks, and even started to pit due to electrolysis. EPDM (ethylene propylene diene terpolymer) had been used on commercial buildings for several years. Many RV manufacturers migrated to that material as it was an easy installation and cheap. However, it did require cleaning and conditioning. Today there is EPDM, TPO (thermoplastic polyolefin), PVC (polyvinyl chloride), Alpha, and who knows what else will be used tomorrow.

EPDM starts as a black base material and the outside color is added with a chalk-like material which can deteriorate and show the black underlayment, which makes the roof look bad. I have been told that Dawn dish soap amplifies the deterioration, although nobody has any actual data or proof.

That, in my opinion, is the problem with most roof cleaning and conditioning products, i.e., most of the posts are just opinions with no data or longevity testing. I know hundreds of people who have used Dawn dish soap for years and the rigs look great and have no leaks. However, some have found dull sidewalls and bad-looking roofs. Part of the issue is the exposure to sun and other elements—especially the hot sun in the Southwest.

TPO material has the color inherent throughout the material so you do not see the fading and black “peeking” out like EPDM. So, once again, I believe Dawn dish soap might be appropriate.

Alpha Systems has products which are branded as PVC. It recommends Murphy Oil Soap, which I believe can be used on most of the rubber membranes as well.

There are hundreds of RV roof cleaners that are being marketed and it is hard to tell what they are made of. When you look at the MSDS (Material Safety Data Sheet), most are more than 95% water and then list inert material. I believe most of them are about 1-2 oz. of a liquid detergent in the mixture.

But what about mold and mildew

I have been conducting seminars for more than 25 years at RV shows throughout the country. I have seen over 100 different vendors hawking the “greatest roof coating.” Just like any product that has been used in a residential application, these products jump into the RV market when it is at the peak and profess to be the expert and then disappear when the market drops, like in 2008 – 2010.

This past year I came across RvRoofMagic from a reader question. I contacted the company and had several conversations with Greg. He even sent product to one of our writers, Cheri, and she applied it to her 26-foot trailer and loved it. I will be doing testing this August on our Forest River Salem demo and will let you know how it performs.

Greg informed me that the key to a successful roof reconditioning is the prep cleaning and getting the mold and mildew spores out of the crevices or indentations of a typical rubber membrane. So I had an “Ah Ha” moment that most of the detergent-based products were designed for grease removal, not mold and mildew. So, if you have a rubber membrane that is not 100% smooth, the spores can collect in the crevices and a liquid detergent will not work the best.

They have a product called Roof Protect, that is a required application before the RvRoofMagic coating and actually has a mildewcide. I did not even know that was a term! Here is his description of how it works.

This eco-friendly, biodegradable cleaner is designed to complement our RvRoofMagic and gives you the best results from your roof coating application. Other cleaners leave streaks and residues that may jeopardize adhesion to a coating as well as still leaving live mold spores on the roof prior to application.

Our Roof Protect emulsifies contaminants and provides improved surface preparation and adhesion by effectively removing oil, grease, mildew, dirt, and other soils from your roofing membrane. It also contains a mildewcide to kill any mold spores on your roof prior to application. You can also use Roof Protect annually to further protect your roof, allowing dirt, grease, etc., to be removed, further extending your roof’s service life. Roof prep with Roof Protect is required for our warranty. One gallon will last approximately 4 washes.

Directions for Use:

• On your initial cleaning prior to the application of RvRoofMagic use a 1:5 ratio with water. For example, 1 cup of Roof Protect for every 5 cups of water. Wash down the roof with water then scrub with a soft bristle brush and thoroughly rinse and let dry before application.
• For subsequent cleanings use a 1-10 ratio. If you are using a power wash with a maximum of 2000 PSI, begin at the lowest point on the roof and work upwards. Once highest point is reached, work down again with a final rinse to remove any excess contaminants from the roof.
• Safety measures: Use protective glasses and clothing when using this product. Do not use on soft painted surfaces at a dilution rate less than 1:30. You can view our safety sheet Roof Protect SDS.
• See SDS and Roof Protect specification sheet for precautions and additional information.

You can find their products here.

Disclosure: RvRoofMagic is an advertiser on RVtravel.com.

 You might also enjoy this from Dave 

I clean my RV roof regularly but now it has black spots. Roof vendor wants $7,500!

Dear Dave,
You’ve been very gracious in the past to reply to my questions, so I thought I’d reach out again. We have a 2019 Grand Design 337RLS which we’ve been living in full-time since October 2020. This is our second straight winter in NE Pennsylvania, so the “four season” RV structure has definitely been put to the test. I’ve been told by Grand Design that the roof is a TPO Alpha Systems material.

Read the rest of Jeff’s question and Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here. 

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