Eternabond Tape to cover all roof sealant ?

[MoonShadow_1911]

From an experienced perspective, do not use it on the factory skylights if you will keep your rig for years to come. You will have to replace them at some point because they embrittle with age and exposure. You will hate the day installing a replacement!

Question, this may be obvious to someone who has used Eternabond but... Would you not be able to cut the skylight out? Cutting around the edge and lifting the tape (still adhered to the skylight) with the edge of the skylight? Then just retape over the Eternabond that was left on the roof?

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[dryfly]

I removed most of the lap sealant mainly to get the old roof vent off and the new one to sit flush. I used butyl tape under the flange and 4" Eternabond on the outside. I also was specific how I laid it down. I did a strip along the back, then the 2 sides overlapping the back piece, then the front strip overlapping the sides. I figure if driving in the rain, the water would naturally flow and not be pushed up against a joint. I've read if you use a heat gun it helps to remove the tape. I don't think the odds of needing to remove the new vent are very high, I'm not too worried about it. Another reason I used the Eternabond was the fact there is no cure time. Lap sealant has a 7 day cure time and I was against upcoming rain when I did the install.

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No, I'm asking about your use of the tape on your front and rear caps. did you remove the lap sealant before applying tape on these seams?

Also, the tape would have to overlap on both the rubber roof as well as the fiberglass. Does it adhere to the fiberglass well?

[FT4NOW]

No, I'm asking about your use of the tape on your front and rear caps. did you remove the lap sealant before applying tape on these seams?

Also, the tape would have to overlap on both the rubber roof as well as the fiberglass. Does it adhere to the fiberglass well?

Sorry, misunderstood the question. No, on both RVs I've done this without removing the lap sealant. I did clean the roof, lap sealant and part of the cap prior to putting the Eternabond down. Yes, it adheres to the fiberglass cap the same as it does to the TPO roof and lap sealant. It has never started peeling or anything like that. I used 6" Eternabond for the front and rear seals.

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[geotex1]

Question, this may be obvious to someone who has used Eternabond but... Would you not be able to cut the skylight out? Cutting around the edge and lifting the tape (still adhered to the skylight) with the edge of the skylight? Then just retape over the Eternabond that was left on the roof?

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In theory, sure. In practice, not so easy. Far easier to explain in-person with some show and tell, especially after I would show you the thickness of RV TPO versus commercial roofing... The simplest thing I can point out if that in the best of circumstances you could drop in another factory unit. However, the quality replacement skylights of the same opening dimensions (ICON models for example) have a larger mounting footprint. Can you make it work out? Sure. Will it be as straightforward as it could be? Nope. Understand one of the building products I manufacture is membrane roofing, and Eternabond is nothing more than a commercial product that a finisher is cutting down and packaging in smaller scale at significant profit. It is a product that has its place, but so does lap sealant.

[MoonShadow_1911]

In theory, sure. In practice, not so easy. Far easier to explain in-person with some show and tell, especially after I would show you the thickness of RV TPO versus commercial roofing... The simplest thing I can point out if that in the best of circumstances you could drop in another factory unit. However, the quality replacement skylights of the same opening dimensions (ICON models for example) have a larger mounting footprint. Can you make it work out? Sure. Will it be as straightforward as it could be? Nope. Understand one of the building products I manufacture is membrane roofing, and Eternabond is nothing more than a commercial product that a finisher is cutting down and packaging in smaller scale at significant profit. It is a product that has its place, but so does lap sealant.

Well put! I thought about that about 30 minutes AFTER I posted... OEM vs Aftermarket. Thanks!

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[Rivercityjeff]

In theory, sure. In practice, not so easy. Far easier to explain in-person with some show and tell, especially after I would show you the thickness of RV TPO versus commercial roofing... The simplest thing I can point out if that in the best of circumstances you could drop in another factory unit. However, the quality replacement skylights of the same opening dimensions (ICON models for example) have a larger mounting footprint. Can you make it work out? Sure. Will it be as straightforward as it could be? Nope. Understand one of the building products I manufacture is membrane roofing, and Eternabond is nothing more than a commercial product that a finisher is cutting down and packaging in smaller scale at significant profit. It is a product that has its place, but so does lap sealant.

Rob, with your product experience, where on the roof would you recommend applying Eternabond? Specifically for those keeping an RV for 5+ years?

Thank you.

[geotex1]

Rob, with your product experience, where on the roof would you recommend applying Eternabond? Specifically for those keeping an RV for 5+ years?

Thank you.

Outside of the problems the very thin TPO has, the biggest problem is the adhesive in the RV industry. It's been formulated for use by truly unskilled labor and attempt to ease effort for future replacement. So the peel strength is poor and frequently there is insufficient bond to the substrate, especially at edges. This poor quality bond also promotes excessive tensile forces to develop during heating and cooling cycles. So, where there is good clamping, such as a flanged roof vent with typical perimeter fastening it does not offer benefit but is just a higher priced lap sealant replacement, especially when the accessory has been set with a proper sealant bed. Where I think the tapes shine is at use at end transitions in the long axis. Said another way, at the front and rear cap/wall transitions. This is because the RV industry does not transition as one would in the roofing industry via batten strip. The try to, but the materials clamping are not rigid enough, and if they were the fiberglass caps, for instance, would crack. The long direction is where the greatest tension forms during heating and cooling cycles and the membrane pulls away from the transition. The tape bonds well to the dissimilar material of the cap or aluminum trim as well as the membrane so it acts to provide additional resistance to than shrinking. Problem I see with the RV industry, they are not using a wide enough width here...

It goes without saying the tape is your best avenue of repair as RV TPO is too thin for thermal field repairs.

A lot of folks get a false sense of security taping everything up, but sometimes it is just the opposite and often unnecessary. RV roof membrane needs regular inspection because of how thin and poorly bonded it generally is and I have heard more than one taper say they forget about the roof after it. One such person is a friend and had no ideas embers from his fire put holes through the membrane and had a horrible discovery after many feet of snow this last winter... I also know a huge fan of tapping everything on my old FR forum spent more money of rolls of Eternabond to tape the entire perimeter, skylights, vents, and roof appliances than what a roll of the commercial grade stuff I manufacture would have cost.

[BB&LAB]

From an experienced perspective, do not use it on the factory skylights if you will keep your rig for years to come. You will have to replace them at some point because they embrittle with age and exposure. You will hate the day installing a replacement!

Exactly, I have been planning to install Eternabond over sealant, but plan to NOT do around the vent fans and skylight for this reason. In reality lap sealant when properly applied holds up well and only requires periodic checks and fill in cracks when they occur.

[Redapple63]

Outside of the problems the very thin TPO has, the biggest problem is the adhesive in the RV industry. It's been formulated for use by truly unskilled labor and attempt to ease effort for future replacement. So the peel strength is poor and frequently there is insufficient bond to the substrate, especially at edges. This poor quality bond also promotes excessive tensile forces to develop during heating and cooling cycles. So, where there is good clamping, such as a flanged roof vent with typical perimeter fastening it does not offer benefit but is just a higher priced lap sealant replacement, especially when the accessory has been set with a proper sealant bed. Where I think the tapes shine is at use at end transitions in the long axis. Said another way, at the front and rear cap/wall transitions. This is because the RV industry does not transition as one would in the roofing industry via batten strip. The try to, but the materials clamping are not rigid enough, and if they were the fiberglass caps, for instance, would crack. The long direction is where the greatest tension forms during heating and cooling cycles and the membrane pulls away from the transition. The tape bonds well to the dissimilar material of the cap or aluminum trim as well as the membrane so it acts to provide additional resistance to than shrinking. Problem I see with the RV industry, they are not using a wide enough width here...

It goes without saying the tape is your best avenue of repair as RV TPO is too thin for thermal field repairs.

A lot of folks get a false sense of security taping everything up, but sometimes it is just the opposite and often unnecessary. RV roof membrane needs regular inspection because of how thin and poorly bonded it generally is and I have heard more than one taper say they forget about the roof after it. One such person is a friend and had no ideas embers from his fire put holes through the membrane and had a horrible discovery after many feet of snow this last winter... I also know a huge fan of tapping everything on my old FR forum spent more money of rolls of Eternabond to tape the entire perimeter, skylights, vents, and roof appliances than what a roll of the commercial grade stuff I manufacture would have cost.

Great explanation of how the RV industry works and the materials used.

Food for thought: typical TPO membrane used on RV’s is .020” thick where a typical commercial application is .060” thick. Three times thicker.

Thanks,
Bill


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[John303]

I have been thinking of doing this on my rig because I had my first small leak a few weeks ago. Smothering the front roof/cap seam with new caulk took care of it, but I am on borrowed time. I see that Eternabond also makes various primers/conditioners, and wondered if anyone use them? Or just a good cleaning with detergent to take care of any wax that may be on the cap?