Roof sealant advice requested. Silicon on shower skylight?

I am looking to buy an older (2005) Fleetwood Excursion that according to the original sales brochure uses the Royal Tuff-Ply (TPO?) roofing material. The current original owner has never done anything to the roof, but for most of its life, was stored inside when not in use, so I feel like this must have contributed to its apparent longevity. I have inspected the roof and there are cracks evident in the lap sealant, but absolutely no evidence of any leaks inside. In addition, the skylight over the shower has what looks like a ton of silicon sealant around the edge.

With no evidence of leaking inside, I am thinking about going ahead with the deal, but would like to get the thoughts and opinions of other members here first.

I am fairly new to owning motor homes, but did own a 1999 Coachman for about 3 years, until a deer decided it was worth his life for me to not have it anymore.  : It had significant roof sealant issues and I want to avoid that at all cost this time.

If we do the deal, I plan to reseal the coach as soon as I get it home, but would like to know what others on here think.

Everything I have read said that silicon on a roof is a no no, but the owner says he did not put it on there. Would a dealer do this? He says as far as he knows, it has been that way since he bought it. Do they make clear roof sealant that ?looks? like silicone? I did not actually touch it, so cannot say for sure it is silicon, but it sure looked like it and it was really gobbed on there. If it does turn out to be silicone, I have some silicone remover, but will it damage the roof?

In addition, any thoughts on possible leaks that are not apparent from the inside of the coach? I do not think there is any way to know for sure without dissembling the roof, but would be interested to know what other more experienced folks think.

Thanks in advance for any feedback.

David

I would find out what type of sealant it is. if silicone I would remove and use the Dicor products. do the job yourself to make sure it gets done correctly, I would put nothing past a dealer
If it has slide outs look for leaks around the seals and at the floor.
from the inside open the a/c where the filter is and look in there for leaks too.
the window sealant might also need to be removed and replaced with new

As far as inspection I would tear everything apart and out that is reasonable.  Removing vent/AC trim, etc. And look for any past trouble.  If the owner had an issue with it I would walk.

That said silicone doesn't stick worth a crap to lap sealant or to rubber roofs.  Maybe if its super clean.  But in my experience it lifts off relatively easily (made the mistake once  :)  I'm not aware of clear lap sealant.  Not to say it doesn't exist, but as you mention the two are very different in texture.  I'm wary of removing silicone with any solvents anywhere near a rubber roof.  I think it should peel off, but needs to be removed.  The lap sealant won't adhere to it.  I would also be extra wary that someone place a lot of something on the roof. 

They have some clear sealants they used on my roof sparingly.....like just to cover some screw heads.  I never did find out for sure what it is, but it wasn't silicone.

If it is silicone, you'll have to scrape it away as best you can....scrub with mineral spirits...scrape some more....and repeat, and repeat again and again.  Nothing else will stick where the silicone was...not even more silicone.  Horrible stuff.

Then I'd reseal it with a proper lap seal or something like eternabond

And even Eternabond won't stick to silicone. It's great stuff though.

Yes, Tuff-Ply is TPO. Most lap sealants work fine on TPO - it does not have the compatibility issues of EPDM. That said, Dicor Lap Sealant is an excellent product for any roof.

Why do you think that sealer is silicone? The factory certainly didn't use silicone there, and you say the former owner apparently did nothing...  Is it clear? Does it peel away fairly easily once you get an edge loose?

Some shower skylights use a plastic that may be sensitive to regular EPDM lap sealants and cracks may result.  Fleetwood used Surebond SB140 Elastomeric Rubber sealant at the factory, but I used products like Geocel Proflex on mine.

I would spray the whole RV in Flex Seal. Then you can drive on lakes too.

SkateBoard said:

I would spray the whole RV in Flex Seal. Then you can drive on lakes too.

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But you'll have to talk really loudly when doing it, so it may not be ideal for everyone!

blw2 said:

But you'll have to talk really loudly when doing it, so it may not be ideal for everyone!

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Ha ha ha ha, I know, he's annoying