Metal Roof Resealing: Do I need to tape, too?

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Joined
Jun 13, 2021
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New York
I picked up a 1992 Class C with low miles. I'd like to reseal the roof. It's metal to fiberglass sides.
I have not seen any leaks, but there are cracks (crazing) in what's up there. (See pics)
In order to reseal this I understand I need to scrape off the old. But do I need to tape the metal to fiberglass seam before covering it over? If so, with what?
And what do I seal this with? Not looking to cover the whole roof, just sealing what already has been.
Thanks!!!
 

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Gary RV_Wizard

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Hairline cracks in the sealant (and presumable NOT in a metal roof!) are common and it's kind of a crap shoot to guess if any of them are deep enough to allow water penetration. The area around the skylight looks ready to be scraped off and replaced, and a few spots elsewhere in those photos. In a roof that old, a complete resealing would be a good idea for peace of mind.

Has the metal been overcoated with a rubber roof coat product? Are all those sealant patches good? I don't think you could successfully put tape over such rough & thick sealant.
 
Joined
Jun 13, 2021
Posts
8
Location
New York
Thanks for the help.
My plan was to scrape and replace it all. No, it's not coated everywhere. Just the seams,penetrations, and patches.
My question involved "after" I scraped it off. Do I tape and then coat thise areas with something?
Or just apply something without taping?
Or do I only scrape what is loose?.
 

TheBar

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Jun 25, 2018
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1,070
Location
MS
Get the rough places off then tape. It looks like it is so old you might be able to sand it smooth otherwise use a razor blade knife. Wash all surfaces with a strong detergent before applying tape and cover all the edges of the old caulking by at least 1/2 inch.

I had major water damage to one RV just over one winter because caulking is a never ending battle. When I bought my 1997 C in 2014 I put 110 feet of 4 inch Eternabond tape covering everywhere there was caulking, overlapping all 4 sides where the roof met the walls, all vent covers, etc. Eternabond stays stretchy so it never cracks and is good for 20 years. On a Class C make sure you caulk the front window around the rubber gasket since that is the most likely place to leak. Also caulk any rounded trim and around the clearance lights. I use clear Geocel Proflex caulking where I do caulk so it doesn't show.
 

Deano2002

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Apr 21, 2013
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884
Location
Morris, IL.
when I bought my old uncared for class A with a metal roof I ended up taping everything because many recommended it. If I new what I knew now I would have never did that, I would have scrapped off the old and any rusty spots would have been cleaned up and new Dicor lapp sealant would have been applied, it just looks so much cleaner and professional, tape looks like a cover up fix
 

jmack108

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Joined
Jul 8, 2021
Posts
17
Location
Radcliff KY
Get the rough places off then tape. It looks like it is so old you might be able to sand it smooth otherwise use a razor blade knife. Wash all surfaces with a strong detergent before applying tape and cover all the edges of the old caulking by at least 1/2 inch.

I had major water damage to one RV just over one winter because caulking is a never ending battle. When I bought my 1997 C in 2014 I put 110 feet of 4 inch Eternabond tape covering everywhere there was caulking, overlapping all 4 sides where the roof met the walls, all vent covers, etc. Eternabond stays stretchy so it never cracks and is good for 20 years. On a Class C make sure you caulk the front window around the rubber gasket since that is the most likely place to leak. Also caulk any rounded trim and around the clearance lights. I use clear Geocel Proflex caulking where I do caulk so it doesn't show.
Great information. Thank you. I'm in the same boat as the OP. This helps. Thank you.
 
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