Weather proofing fiberglass roof and body

[Cabana72]

Alright guys, so first up on my 1972 Cabana is sealing it up.  It is not waterproof at all.  I think it's leaking a lot more here at her new home than she was at her old, no way it's been leaking this bad for years and isn't in much worse shape.  A brief survey shows lots to be done on the roof, several spots on the body, doors, and a few miscellaneous places such as obsolete mounting holes and marker lights.  The inside does show several areas of water damage, but no visible mold or much obvious rot.  On a recent frog strangler rain storm I was able to collect about a gallon from a roof vent and cab drip.  The rear bathroom floor was also wet but didn't have a visible drip.


Lets start with the roof as it's the worst offender.  I think most of you have aluminum coaches, so although I have read around a bit I just want to see what might be different on fiberglass.  Here are some pics of where we are starting.
[smg id=7719]
[smg id=7721]
[smg id=7718]
[smg id=7720]
[smg id=7716]


The PO (definitely not an rv maintenance nerd) refers to the goop at the front and rear seams as "lap seal" and has just suggested I slop some more on.  I'm leaning more towards eternabond just because ya'll love it so much, but does anyone have experience using it on fiberglass vs. aluminum?  Any tips for stripping off what is already there?


But for those seams, why bother with tapes, goops, or anything when it seems to me a simple strip of fiberglass and a bit of resin would seal it up permanently, and may even be cheaper than eternabond?  Do I need flexibility at that seal for some reason?  Am I likely to ever want to remove the fiberglass ends or roof and thus really don't want a permanent FG seal? 


[smg id=7722]
For the big openings like vents, ac etc I guess I just strip whatever is there and replace with eternabond?  Is eternabond reusable as in if in a week or two I replace a vent does the eternabond get replaced too, or does it stay "fresh" for a while?


Due to the water intrusion, there are some significant soft spots on the roof, as well as water damage to some interior roof panels and walls.  Overall the roof feels solid walking around, but there are definitely some concerns.  I'm assuming that I'll address them from inside, but I do wonder if this entire FG roof could/should be pulled off relatively easily.  I can see how it's all held together from the outside, but have no idea what could be glued or screwed from the inside.
[smg id=7715]
For smaller areas, like the roof rack supports, what is a good approach for sealing them?  Silicone?  Small patches of eternabond?  I do note that some of the soft spots are inline with or even at the roof rack supports.  This really makes me wonder if I need to remove the roof and/or interior panels to address structural issues before permanently sealing the roof penetrations.  I also wouldn't mind removing the roof rack for painting (will do the bumper and ladder anyway) but I am a little hesitant that sometimes replacing screws in suspect materials causes more difficulties if I'd be able to get by without replacing underlying stuff.
[smg id=7717]
I also have a couple things like this that I don't even know what they are/were.  I'm about 50/50 for sealing them with the idea that I'll want them vs. removing them and sealing in some sort of cover plate/plug since I don't know what they are anyway.

[Rickf1985]

Avoid silicone like the plague! It is bad stuff, once used nothing will ever adhere there again and the silicone is a lousy sealer on RV's. I would not epoxy the seams due to the fact that they probably need to flex there. Eternabond is your friend here. Everywhere you show, especially all the roof seams in the front and back need to be stripped to the bare beginnings. Not fun at all and tedious at best but once done you put the Eternabond on and you are done with it. That roof rack is steel and I will bet is is rusted just about completely out from the inside. I would eliminate it and cover the holes with eternabond. Face it, what are you going to put up there that you need the rack for?

I use Eternabond, actually a generic version of it I get from a roofing supply, and Pro-flex caulk for everything I do on mine.

[legomybago]

Eternabond, Eternabond!! Once it's installed, you are not going to remove it. I wouldn't use Eternabond on vents or items that are going to need replacing in the future due to UV rays like plumbing vents. Replace your plastic vents with now with new, and all your plumbing vent caps. Use butyl putty tape as the gasket on vents, then top off with this to cover your new screws http://www.amazon.com/Hengs-46032-Rubber-Roof-Coating/dp/B004A32HEA/ref=pd_sim_sbs_263_1?ie=UTF8&dpID=41KMdN7ElBL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=1QWR8WQFM0J3R7W8P9D5
Eternabond the end cap seals and wherever you may have holes. I use a 4 or 5" grinder with a wire wheel attachment to remove mounds of $hit applied over the years by PO's, you just need to be careful and take your time working around the fiberglass roof, only remove the sealers. That silicone will probably just clump and fly off with the wire wheel, you'd be surprise how efficient it is.

[Rickf1985]

Eternabond is not all that hard to remove. Heat gun and putty knife and it comes right off. How often are you planning on removing it?

[legomybago]

I've never attempted removing Eternabond myself, only applied it, and whatever it touched, it welded itself to, so I just figured it would be a nightmare to remove? Every RV I've owned needed plastic roof do dads replaced from time to time due to old age or tree branch damage.... so I like to keep some items serviceable.

[Cabana72]

Is it easy to form tape (eternabond or butyl putty) around round things like vents?  Just wrinkle and bend?  Lots of short pieces?  Some other wizardry?

[legomybago]

If you read my original answer to your question, you'd see I don't personally think people should cover anything that is consumable over time with Eternabond tape, the next owner to your RV will be cussing YOU when they need to do some plastic parts replacement on that roof, and they find that all the screws are covered in Eternabond tape   no it doesn't really bend. Getting on the roof with a heat gun and a putty knife are not what I call a good time.

Butyl tape comes in a roll, it's the same basic thing as plumbers putty, but on a roll. It works great for all shapes.

[Cabana72]

Gotcha, it's not really a tape.


So the air vents do need replacing, probably should get some good fans as well.  The stove vent (I think, maybe it's the fridge, oblong thing) needs replacing too, it is cracked plastic.  But why replace plumbing vents, they seem to be metal and solid?


Any thoughts on how the roof is constructed, as in what holds it down?  I have screws every few inches around the perimeter and at each seam.  Most of them are rusted so I thought I'd replace them.  If I have all the screws out and all the vents/AC etc removed is the roof just sitting there waiting to be lifted off, or was it likely glued or bonded somehow to structure beneath?  Seems it'd be a shame to not at least take peek and see the condition in there. 
Heck, the rear cap seems to be held on the same way, with a row of rusted screws over a trim piece.  Maybe before I seal the seam I'll take out the screws, remove the bumper/ladder, disconnect the rear lights and try to pull the rear cap off to take a peek there too.  Anybody removed a FG end cap or roof?


When I do replace the screws, do I do anything seal them?  A shot of caulk or something in each hole?

[legomybago]

Personally, I wouldn't remove any of your front or rear end caps, they might go "BOING" and make it difficult to replace!!
I would definitely replace the rusty screws, use the lowest/flattest? head Phillips style screw you can find (Eternabond will cover and seal better over a smaller bump). Don't use a hex head bolt where Eternabond tape will be used. MO
They make plastic and metal plumbing vent caps, if yours are in good shape, then your good to go.
You can buy 4" wide Eternabond tape, it will cover seams well. If you use Eternabond tape say, on an 75 degree day in the sun, look out! It will stick like a mofo.

[CoastalWinnebago]

My $0.02 is a in line with some and a bit more specific to aluminum roofs. 


I had similar rot and water intrusion.  I will only use eternabond after I have spent time with it.  In my opinion, as a materials engineer, this material is state of the art.  It has excellent adhesion to nearly every material, can be formed like a putty if needed, and sticks like crazy.


My personal opinion on butyl tape is that it is an outdated technology.  Why would you utilize a material that is known to rot, weather, and overall fail after a given amount of time.


Do not, for any reason, ever use silicone for this application.  Once its there, you will never get anything else to glue to it.  The surface tension of Silicone is such that nothing will stick.


To remove the old stuff, buy a lot of razor blades, an orbital sander, and some goo-be gone (I would suggest acetone, but I do not know if it will degrade your fiberglass roof material).  Scrape bulk material off with razor blade, apply goo-be gone with rag and scrub.  Run orbital sander with 150 grit to remove remainder.  Paint over the fresh surface, then apply eternabond.  I have posted photos of this process in the past for a reference.


Replace vents and vent caps while your up there, its worth the money for the peace of mind that you won't be re-doing the job because the old weathered plastic cracked after the strain from being re-mounted slightly different than how it lived for 30 years.

[legomybago]

"My personal opinion on butyl tape is that it is an outdated technology.  Why would you utilize a material that is known to rot, weather, and overall fail after a given amount of time."

I agree on butyl being old school....We are all still using Plumbers Putty too. It works.
What do you use in place of butyl tape? Under the flange of something you mount?
Thanks

[CoastalWinnebago]

Im really starting to sound like a "homer" but I had very good luck with double sided eternabond.  I am actually doing a test on my rig.  On one pipe vent I used eternabond, and the other I used butyl tape.  I figure I will end up replacing the butyl tape, but at least it will be an easy fix since it doesn't actually "stick"

[Rickf1985]

I swear by eternabond, actually the generic (and much cheaper) version of the same stuff. But double sided I don't know if I would go that far. IF it ever had to be removed then heat would be the only way and it would destroy whatever you were trying to get off. Of coarse I am open to ANY replacement for butyl! It works fantastic................... for a year or two and then it dries out and leaks like a screen door.

[Cabana72]

Hey rick, can you share a link to the generic eternabond you've had success with?  I searched your posts but didn't see if you've posted it before.
Thanks.

[Rickf1985]

I'll have to dig it up, Too tired right now, long day of driving. Will get it tomorrow. You can get it at any commercial roofing place. I got it from an Allied Roofing supply.

OK, If I wait I will forget D:oH! , here it is.







Same white top and grey adhesive side, Once it touches it don't come back up so make sure you get it right the first time.

[TerryH]

Thanks Rick.

[Cabana72]

Thanks for that tip Rick.  But a heads up if anyone else is shopping, 4"x50' white eternabond is currently on amazon prime for $54(normally $80), cheaper than I could find the roof xtender anywhere online...

[Rickf1985]

THAT is a damn good price!!!!!!!!!!  I paid around 55.00-60.00 for this stuff and that was a couple years ago.

[Rickf1985]

Do you notice on the label it says 30 minutes permanent bond? I defy you to get that off after one minute without a heat gun.    

[legomybago]

Yeah, try 30 milliseconds for permanent bond D:oH!

[legomybago]

Butyl tape for a gasket, self leveling product over the screws and seam.
I use a good grade/brand (RV) clear silicone on the upper seal of my exterior windows, and I use silly-con on misc side exterior imperfections that arise due to age of these old beasts...Silicone does fade in color over time, and if that bothers you, you can always remove the bead, and lay down new. If there IS a product out there to use in place of silicone on the sides of our rigs, Id like to know what it is? Something clear, that doesn't fade in color.

[CoastalWinnebago]

For those arguing against eternabond as side window seals, before I decided to use the double sided eternabond for the windows I emailed their customer service to discuss the application.  They relayed that this application was perfectly appropriate for double sided eternabond. 


The thickness of the double sided eternabond is only slightly thinner than butyl tape, and conforms just as well when put in compression.

YES double sided eternabond DOES work, and is recommended by the supplier.  Please note I am talking about double sided eternabond, not single sided.

Speaking specifically about material properties here are my thoughts on Eternabond (EB) and Butyl:
Adhesion: EB
Compressive Creep Resistance: EB
Tensile Strength: EB
Elongation and elastic return: EB
Oxidation resistance: EB
Weatherability Resistance: EB
Ease of use: Butyl
Ease of rework: Butyl (but if silicone is used with Butyl, EB is better)
Cost: Butyl
Environmental Impact: Butyl


To me, I would rather use a product that is a bit more difficult to apply, but will fix a problem I won't have to re-address in a few years.  Performance is performance, and there is no arguing that eternabond had better material performance compared to butyl rubber.

[legomybago]

I didn't know they made double sided Eternabond....

[Rickf1985]

I use a good grade/brand (RV) clear silicone on the upper seal of my exterior windows, and I use silly-con on misc side exterior imperfections that arise due to age of these old beasts...Silicone does fade in color over time, and if that bothers you, you can always remove the bead, and lay down new. If there IS a product out there to use in place of silicone on the sides of our rigs, Id like to know what it is? Something clear, that doesn't fade in color.

Replacement for silicone would be Pro-flex.

http://www.geocelusa.com/product/all-rv-aftermarket/pro-flex-rva-flexible-sealant-detail.html

[legomybago]

Replacement for silicone would be Pro-flex.

http://www.geocelusa.com/product/all-rv-aftermarket/pro-flex-rva-flexible-sealant-detail.html

It's got to be good Rick if they won't sell it in California! (Except crystal clear).