Factory roof seal ?

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If you search the forum you'll find lots of testimonials about rv liquid rubber. There are several brands that really are liquid rubber. It is used by a lot of commercial roofers.

Unlike most folks here I'm too lazy to re-caulk and re-coat every few years. I had damage to a Class A years ago because 3 year old caulking failed over the winter. I wanted a solution I wouldn't have to touch or worry about for 20 years.

I used Eternabond tape around the sides and vents then this brand over it. Took 4 hours on a 30' RV. I still wash and check the roof twice a year but 8 years later no recoating and no caulking required. My only complaint is fallen leaves over the winter did stain it. But otherwise like new.
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I should have taped over the screws in the end caps. A screw worked out and caused a small leak 1 1/2 years ago. I had to cut it to get to a carpenter ant invasion and it was as flexible as the day I put it on. I just sealed up the cut edges with Eternabond. And taped over the d!$@ screws.

Eternabond and Liquid Rubber sticks to almost anything, even bare wood, and should last over 20 years. It is initially more expensive than cheaper coatings but it is overall cheaper than re-coating every few years. Plus my time is worth something. If you decide to go this route I bought the recommended 5 gallons but only needed 3 1/2 for a 30' roof.
 

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As a dedicated dedicated Eternabond fan I have changed my mind..
There is a YouTube video somewhere around that shows a guy literally peeling on what should have been a permanent Eternabond seal from the shower cap to the roof of some sort of Winnebago. My Eternabond seal from 10 years ago peeled off exactly the same way, and there were plenty of moisture intrusion tracks found too. On the street side I had used a wide strip of Eternabond tape to fix a crack thinking it would be a great seal. Nope.. it peeled off exactly the same way. In the meantime the 311 sealant is completely intact everywhere else on the roof where I haven’t touched it. So back to the OEM Sealant that, applied correctly (and it just was) would/ should outlast me.. at $18-20 ea. it’s expensive since it took me 3 full tubes to recreate the amount of seal used at the factory. It sure is pretty tho.
 
Maybe the right question to ask then is what would be the procedure to properly prep silicone for reapplication? Are there incompatibilities between different types? I think the "can't recoat" comes mostly from trying to apply a lap sealant like Dicor over the top of silicone, which absolutely doesn't work. So it's "common knowledge" you don't use silicones on RV roofs because once you do, you can't use most anything else over the top of it. I've had more or less success over the years re-sealing things with silicone, generally the major part of it is removing the compromised seal as just gooping more over the top isn't going to last. Prepped right it's pretty darn durable, I've got some utility boxes on my radio tower where the silicone bead I put on them almost 20 years ago have "tanned" but are still pliable and solidly adhering. When I first got my RV I remarked over the 311 seal WBGO used and how well it had held up in New Mexico sun. When I get around to replacing my cracked skylight there is no doubt I'll be repeating that process.

Mark B.
Albuquerque, NM
Ummmmm…. Have you priced out your Skylight?
I had 3 cracks coming up from the edge and figured I would replace it since I am playing roofer this week anyway. UNTIL….. I got a message back from Lichtsinn that the cover is $700.00 ( S e v e n H u n d r e d Dollars..). Nope..
 
I have been lurking here on this forum for a long time so feel like I already know some of you:)
This is my first post though
Re-sealing my bathroom skylight on my 2010 Winnebago Sunstar 26P. I have it removed and have spent hours cleaning the roof and the skylight itself. I have been reading and finding all the information I can on roof and vent resealing here on this forum but may have just overlooked the answer. I plan on using Nuflex 311 self-leveling all around the screws and perimeter. My question is what is used under the skylight itself between it and the fiberglass roof? In addition, this skylight has the four rounded metal screw down clamps on the four corners holding down the four corners of the skylight with no other screws in the skylight. It looked like they just used Butyl under the metal that extended out past the skylight and screwed to the roof, would this be correct? Not knowing what the previous owner did I have no idea.
 
Welcome lurker! :)

I think there might have been some sort of a sealing tape under the skylight but if I was doing that job I would smear some of the 311 around the roof opening and position the skylight on the roof. As far as the clamps, use a little gob on the screw hole. Place the clamps, screw the clamps down and then run 311 around the skylight perimeter and over the clamps.

Use enough 311 to where it extends out from the skylight edge about 1/2"-3/4" and a nice goop over the clamps. Be sure and use fresh sealant otherwise it won't flow out properly.

As far as not using a sealing tape under the skylight, this assumes its base is not warped and is thick enough to squeeze out a little bit of 311 when you clamp it down. First - Do a dry fit including using the clamps and examine the gap between the roof and skylight. If there's little to no gap then I believe just using the 311 under the skylight flange would work fine.

If you don't feel comfortable with my process, use a butyl tape under the skylight flange.
 
Welcome lurker! :)

I think there might have been some sort of a sealing tape under the skylight but if I was doing that job I would smear some of the 311 around the roof opening and position the skylight on the roof. As far as the clamps, use a little gob on the screw hole. Place the clamps, screw the clamps down and then run 311 around the skylight perimeter and over the clamps.

Use enough 311 to where it extends out from the skylight edge about 1/2"-3/4" and a nice goop over the clamps. Be sure and use fresh sealant otherwise it won't flow out properly.

As far as not using a sealing tape under the skylight, this assumes its base is not warped and is thick enough to squeeze out a little bit of 311 when you clamp it down. First - Do a dry fit including using the clamps and examine the gap between the roof and skylight. If there's little to no gap then I believe just using the 311 under the skylight flange would work fine.

If you don't feel comfortable with my process, use a butyl tape under the skylight flange.
John thanks for that information, I think that is what I will do. This is my first go around with a fiberglass roof so still learning all I can about keeping it sealed. There are signs that the skylight had a small leak so that is the reason for resealing. The shower vent cap is so close to the skylight that it is hard to get sealant between the two so doing both at the same time and going to try to shape the sealant in a way to make the water run off instead of just pocketing between the cap and skylight as it has been doing. I am learning so much about sealants here I appreciate the information.
 
I’d do, and did just what John said. Looking at my admittedly excellent job many months later, it looks “factory”. Thats what I was looking for.. something that won’t shrink or dry out and remains squishy. Silicone….. Who knew?
 

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