rubber spray sealant on roof

silversand wrote:

The Airstream and one Bigfoot were used when I bought them (a couple of years old) the others were new. Within 2 years of manufacture the Dicor was failing on all 5. I would call that 100% abject failure...

This could be because of cheap Chinese knock-off product creeping into the industry (or, it isn't Dicor: read the post above). Buy your sealant directly from Dicor, if you want to be absolutely sure it is the real thing (and not stale!). And, as your camper manufacturer precisely what they had used.

I have no way of knowing what the actual material was. But I did ask both Bigfoot and Monoco directly, and was told by them it was Dicor. I didn't ask Airstream, but the stuff looked (and failed) identically. In addition, almost any 3+ year old RV roof I have looked at that has this type of product has signs of failure or complete failure. Now this is California where the sun shines a lot. This stuff turns hard and brittle over a fairly short life. Up north or back east with not much sun, maybe it lasts longer.

Drizzling stuff on the outside of a joint isn't really a great way so sealing anything, though it is easy to do. Kind of like putting the valve covers on you engine dry, then wiping sealant around the outside and expecting it to keep the oil in.

Also, professional elastomeric roof coatings are and have been used on the roofs of many manufacturing, government and private roofs for many years now. The technology is well proven. Elastomeric coatings can even be used on high-traffic floors in manufacturing plants, without any worry of wearing off.

If you want to investigate this further, ProGuard Coatings is a manufacturer of such products, here-->

ProGuard even makes elastomeric polymers to coat directly over EPDM and TPO roofing. If our TPO roofing would ever need replacing, I will use this elastomeric material rather than re-roofing. YMMV.

Remember: not all TPO roofing materials are manufactured alike! make sure you know when, who and precisely what TPO thermo-plastic compounding was used to make your roof sheeting before you apply ANY sealant.

The Airstream and one Bigfoot were used when I bought them (a couple of years old) the others were new. Within 2 years of manufacture the Dicor was failing on all 5. I would call that 100% abject failure...

This could be because of cheap Chinese knock-off product creeping into the industry (or, it isn't Dicor: read the post above). Buy your sealant directly from Dicor, if you want to be absolutely sure it is the real thing (and not stale!). And, as your camper manufacturer precisely what they had used.

Go with Dicor!....pics from HMS Beagle are Plas-t-cote breaking down, not Dicor. Bigfoot used Plas-t-cote around roof vents. Plas-t-cote needs regular maintenance moreso than Dicor. Plas-t-cote will chip off, Dicor will not. I own 2 Bigfoot rv's, and I use both products.

I like that. What's on there has seoerated from the rubber roof. Sounds like this stuff I could just add to what's there. I don't have much time to invest. I'm personally remodelling my kitchen and dining room.

This is my preference, and what I have used for years. I do not recall of going to any RV parts store, or building supply store that did not have it on the shelf. It gets very firm, but remains pliable with your fingernail. This allows flex between two surfaces. It is not easy to remove. I appears to be what was used on my 1988 Bigfoot. You need only put it over the cracks, no need to spread more than 1/2-inch wide.

All I know is, I have had 5 RVs with Dicor on the roof: 3 Bigfoot products, one Safari/Monoco, one Airstream/Thor. The Airstream and one Bigfoot were used when I bought them (a couple of years old) the others were new. Within 2 years of manufacture the Dicor was failing on all 5. I would call that 100% abject failure (unless success is defined as outliving the manufacturer's warrantee). The picture is from my latest Bigfoot, manufactured 2008 (picture was taken in 2013) so 5 years old, but had obviously failed long before. The complete separation happens on some of the slippery plastics like that refrigerator vent (polypropylene I think) and is actually a Godsend as you can at least remove the failed remnants easily. It was not leaking because of the polybutylene sealant underneath between flange and roof. That is not a unique occurrence, I have many such pictures.

If you must apply something over the top I have had better luck with Eternabond - though the ugly Dicor must be removed first to give it any chance. Wet sealants don't do much good unless they are between the sealing flange and the roof.

I know many here swear by Dicor, the usual advice is that you must slop on some more at frequent intervals. I would rather use a product that can be applied once and last 10, 15, or even 20 years. Fortunately Sika and 3M have been making such products for decades in the form of PU, PE, and PB based sealants. They are more expensive and more difficult to apply which I suppose explains why the RV industry does not use those - and any life beyond the warrantee is of little benefit to them.

HMS Beagle wrote:

WyoTraveler wrote:
Dicor is a trusted well known product.

Certainly not by me. In fact I would gladly pay a couple of hundred to have Dicor come and remove all their failed product from my roof. A lot of it removes itself, but the stuff that's left is a mess.

It would almost make you wonder if that is actually dicor. I haven't seen a lot of rv roofs but I have seen some old ugly dicor and it's never seemed to age like that. I have never seen it completely separate like that. It's usually cracked and still a pain to remove.

What is the inspection interval that let you find it in that advanced stage? Was water dripping from the ceiling?

Well my mind gas been made up. Dicor it is or something comperable. Thanks for the advise. And for the record I don't watch much TV, my A.D.D. makes sure of that.

HMS Beagle wrote:

WyoTraveler wrote:
Dicor is a trusted well known product.

Certainly not by me. In fact I would gladly pay a couple of hundred to have Dicor come and remove all their failed product from my roof. A lot of it removes itself, but the stuff that's left is a mess.

I don't know what your problem is/was, but I just worked very hard to remove Dicor from a vent that I installed an A/C unit in. The Dicor had been in place for 16 years living outside in Pennsylvania for most of those years.

Having the roof material, vent metal, etc. all clean, the Dicor should last a long long time.

I tried a can of the white spray sealant around the vents on my Motor Home last year. When I was installing the A/C, all that "miracle spray sealant" would just brush off using my hands.

Don't waste your money!