Roof seams need to have the seals renewed periodically to prevent water from getting into the wood framing and causing rot. If a LD is properly sealed, the coach will last for decades, if not, rot can destroy a coach's frame in just a few years. The roof seams done at the factory last about ten years. When it's time, you have two choices return to the factory or use Eternabond.
Eternabond is a 4"-wide self-adhesive tape, available in either white or aluminum finish (paintable). "Adheres to almost any surface (except silicone) instantly and permanently. Will not harden, shrink, streak or ooze," says the description.
The advantage of Eternabond over Parlastic is that you can reportedly apply it over an old seam with proper preparation--whereas with Parlastic, you must clean off ALL the old sealant, right down to the metal. Those who have done it say that's a real PITA job, with lots of time spent on your knees scraping off the old hardened stuff, applying nasty solvents and scrubbing away the remainders.
The key to a lasting Eternabond application is to do a thorough and painstaking cleaning and surface prep process; the prep takes time, it's "steppy" and tedious, it's hard on the knees, and there are no "do-overs"! If the surfaces aren't very clean and well-prepped (or if the E-bond is applied over an "incompatible" surface), and/or the tape isn't rolled or stuck down carefully, the stuff will lift and/or bubble and the seal can fail.
It's absolutely true that E-bond is a nightmare to remove; if the job is well done in the first place, that's pretty much the point! And, I can surely see what a shop would *not* want to take on the job of removal; even a bad seal job is still a one big time-consuming, labor-intensive mess to take off! But, as to that "never" stuff, I first applied a strip of Eternabond over five years ago to the cabover roof seam because the factory seal had been sloppily done; the seam had bubbled and "leaked" and allowed water and dirt to collect under the seal. I cleaned the seam out, scrubbed and prepped it, ran a deep "bead" of polyurethane sealant, let that dry and "cure", prepped the seam lightly again, and applied the E-bond tape. When I did the roof reseal this spring, this tape showed no lift or other evidence that it had lost integrity, but it *was* weathered and showed a few light surface cracks along the outer edges, and a few of the machine screws had begun to poke through the tape. I fixed those and resealed the seam with another strip of E-bond.
The first major decision you will need to make is whether to put the Eternabond over the existing caulking or to strip off the existing caulking before applying the Eternabond.
Eternabond Installation over existing caulking:
(1) Two 50’ rolls of Eternabond, 4” wide
(2) Ladder high enough so you can safely reach the edge of the roof. Mostly I worked on the roof, but sometimes, like around vents, the ladder was easier.
(3) A wallpaper seam roller, about 1” wide
(4) a nice sharp razor knife
(5) A pair of sharp scissors.
(6) A can of Acetone
(7) Some rags.
(8) A scrap piece of wood to use as a cutting board when trimming the tape.
(9) A tape measure
I’ve done this twice, first on our 2000 then on the ’08. Both times the job turned our just fine. No lifting of the tape, no air bubbles, etc. Basically I followed the Eternabond instructions carefully.
“Side seam” refers to the long front-to-back seam on each side of the LD. “Front seam” refers to the seam where the nose cap joins the aluminum roof.
1) Use soap & water to wash the roof. Let if sit to be sure it’s absolutely and totally dry.
2) On the day of installation there can be no dew on the roof. I started around noon time to be sure the roof was really, really dry. Eternabond will not adhere to water!! If there is moisture under the tape, as soon as it gets hot, the water will evaporate and a bubble will form.
3) On installation day, I cleaned the area to be taped with acetone just before I taped that specific area. Acetone dries instantly. It’s a cleaning product recommended by Eternabond.
4) Neither Eternabond, nor I, saw any need to remove the existing caulk. I suppose if some was obviously loose, I would, but that was not the case with either of my applications. Both jobs came out well; based on that, I’d say removing the existing caulk is overkill of the highest order. Now if some previous fool used silicon on the roof, that’s a different story. Nothing, Eternabond included, sticks to silicon. When you tape over the existing LD caulk and use the seam roller, you will see some ridges or bumps under the tape here & there. Not that it matters or adversely impacts the results, but there are some ridges. If you simply can’t live with the occasional bump, them by all means feel free to remove all existing caulk.
5) When actually laying the tape, just peel back a few inches of the tape liner at a time. Get it exactly lined up, then press in place with your fingers. Roll it tight with the seam roller. The tape makes contact the very instant it touches the roof. Just like using contact cement; you only get one chance to get it right. If it’s a little crooked, not to worry, just get back on your line with the next few inches you apply. The Eternabond instructions address how to deal with little air bubbles should you wind up with some here & there.
6) Start with the long side edge seams. Lay the tape from front to rear. There are two ways to help get this side seam straight. If you have a good “eye” you can just use the existing seam as your guide. Or, use a chalk line and pop a line just where you want the inside edge of the tape to be. I used a chalk line. Even so, there is a bit of a wave in my long side seams. Doesn’t look like a snake, but nor is it perfect. Then again, you need to climb on the roof to see the tape. Mostly that’s just me. That’s why I went with the 4” wide tape. It’s more forgiving then the 2”. Plus the 4” gives a nice 2” coverage on each side of the seam, and in the grand scheme of things, it’s not all that much more then the 2”. The reason you lay the long sides first, is that the front exposed edge of the side seams should be covered so highway speed wind & rains don’t try to lift it up. I placed the front edge of the side tape so the leading edge of the tape was about 1 ½” in front of the front side-to-side seam. That is, the seam where the nose cap & the aluminum roof meet. That way, when I laid the across- the- front tape, it covered the front seam by 2” in front of the seam and 2” in the rear.
7) Working around the refrigerator “chimney” and other vent obstructions takes a little doing. I laid the tape in it’s full 4” width as close to the chimney as possible. I then used the scissors to cut the tape on the inside roof side, just enough to permit me to continue with the run past the chimney. I didn’t remove any tape, I just folded the tape up into an “L”: shape. The bottom of the “L” adhered to the roof; the upright part of the “L” to the upright edge of the chimney. That way there is no seam in the tape itself. Its one solid piece as it passes the obstructions. I used the same general procedure around the different roof vents. Applied the tape up the entire upright part of the vent then the remainder to the roof.
8) I used Eternabond everyplace Lazy Daze used caulk, i.e. around all roof vents, vent stacks, etc. 50’ was just enough.
9) Sometimes the glue from the tape will stick to the razor knife or scissors. Acetone will clean it off.
Removing caulking before installing Eternabond:I was going to Eternabond a 1992 LD when I found that the Factory seam had been generously coated with a coat or two of trailer roof sealant.
The trailer roof sealant barely dissolved when trying all the solvent I had on hand. I also found big rusty hole, under the sealant, in one of the front corners, an area prone to leaks. So the choice was made to remove it all off.
I had bought Rockwell Vibratory tool several months ago for another job and had wondered about how well it would work for removing roof sealant.
I installed a sharp scrapper blade and started slicing and wow!,this thing moves.
It took about two hours of actual work (and a couple water and sharpeningbreaks)to remove the big stuff plus another hour of using a grinder to buff off the remaining sealant. Most of the surface was cleaned down to bare metal. The roof then got two lacquer thinner scrubs, a etching solution treatment, was washed and dried, wiped again with lacquer thinner and was then allowed to bake in the sun. Next a thick bead of 3M-5200 sealant was applied to the all exposed seams and pushed in and smoothed with a gloved finger.
The Eternabond was then carefully applied, trimmed and rolled. Any remaining bare metal was painted.
The whole job took 6-7 very busy hours.
I spend the last 2 days putting eternabond tape on the main seams (2 side, 1 front) on my 2003 MB. The caulk was original, but still in very good shape because the previous owner kept it inside much of the time. I opted to strip all of the original caulk off, which I know many would consider overkill. In my case, the original roof had been painted with a self-leveling rubber non-slip surface to fill some dents from a hail storm. I wanted to get to bare metal as much as possible. I also believe that for a once-in-a-lifetime job like eternabond, it's best to err of the side of surface preparation.
(1) I'm glad my LD is only 26.5' long.
(1.5) 26.5' is longer than you think.
(2) Caulk sticks to caulk better than it sticks to painted aluminum. This means you can pull/peel it off of you can get a grip.
(3) a 5-in-1 paint tool was very helpful for getting a grip and helping peel caulk over screws. A plastic putty knife was too soft, and a metal putty knife was too thin and sharp. The 5-in-1 was solid and not too sharp.
(4) A heat gun actually made things worse. The caulk tore too easily and I couldn't peel/pull it off in substantial strips. Heat + scraping left thin layers of caulk on the metal, while pulling left the painted metal clean.
(5) Heat from inside the coach did make things easier. I could tell a difference in the afternoons when the interior heated up, and I could tell a difference around the refrigerator vent.
(6) Working from a step ladder was easier than working on the roof.
(7) A laminate roller works great for rolling the tape. I had one from a previous counter top job, and they are available at any home improvement store. The laminate roller is similar to the roller sold on the eternabond site, but much easier to acquire.
(8) 2 50'x4" rolls gives plenty to do both side seams, the front seam twice, and still have enough left over for the vents.
(9) I'm a young, strong guy and I'm sore after peeling and pulling for 2 days. Removing all of the caulk is a chore.
(10) I plan to tackle all of the vents and roof rack mounts in the spring. That should be easy after handling the main seams.
(11) I'm very glad that this job will last the life of the coach.
Contributors: Larry Wade, Rich
Revised 2 Aug 11
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