coroplast

[edward willis]

Have a Keystone Cougar 5th wheel that had a flat and ruined a 1ft wide and 2 ft long strip of coroplast. It exposed the underlying wood. I can get the coroplast from Lowes, but my question is. How do I attach it? The wood is exposed and I want to make it as waterproof as possible.......Thanks Guy's.

[JRTJH]

Are you talking about "coroplast" Corrugated plastic about 3/16" thick or are you talking about "Darco" a thin plastic membrane very similar to a "blue plastic tarp" ???

Darco is usually the "cover of choice" in the wheelwells and coroplast is usually only found "between the frame rails in the center (front to back) part of the underbelly.

As for "waterproofing the wood" under either product, realize that the only way to "waterproof the surface" would be to remove all the coroplast or darco and water proof the entire wood surface. Doing a "piece-meal" waterproofing of only the area that you're replacing the outer covering wouldn't do much to prevent water intrusion that usually "spreads like wildfire" when augmented by the "waterproof covering" that typically holds water next to the wood to make sure it's all saturated evenly.... in other words, when you reinstall the water proof cover, it'll keep water out, but any leaks and it'll keep water in equally well. In that case, having a 1'x2' area "waterproofed" won't be of much benefit.

[JRTJH]

You asked, "If I can find the Darco, how do I attach it so it's waterproof"...

You can buy Darco fabric at any mobile home (house trailer) supply store or at most RV service centers that have a parts department. The tape you want to use is called "SCRIM" tape. It's available on Amazon as well as most parts stores above. One link is here: https://www.amazon.com/gp/product/B00BJ5SPO8/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

To attach it, clean the exposed area well with simple green, then wipe down with alcohol. Let that dry thoroughly. Then spray the bottom of the trailer with contact cement, when tacky, apply the Darco to the area. Use a roller or hand pressure with a towel to push the Darco tight against the existing underside covering. Once that is adhered well, use the SCRIM tape to seal the edges. ALWAYS keep the area clean and dry.

SCRIM tape has a paper backing that you'll need to remove, so only remove a small bit of the paper backing, align the tape, press that small part into place, then slowly pull the backing paper and adhere the tape as you go. It's much easier that way than to try to "wrestle a big piece of sticky stuff into position"...

[ajk170]

JRTJH- could Edward also spray the exposed wood with something like "Flexseal" (or something like that) prior to re-patching the hole to further protect that spot from any water penetration that may occur as a result of the patch? Or would that lead to a secondary or tertiary problem?
-Andy

[JRTJH]

Could he? Of course, but I don't know how long Flex Seal will remain waterproof in an area like a wheel well. And, if there's any reason to go back into the wheel well for further maintenance, how hard is Flex Seal to remove?

Sometimes, "armor plating" an area isn't the best approach when it comes to future maintenance. That's sort of my "concern" with using Eterna Bond tape on the roof. As long as it's installed properly AND you NEVER need to get under it for some reason (roof gouged from a limb, screws backing out of a molding strip, etc) then it's a "good repair" BUT.... if you ever have to remove it, you might as well resign yourself that you're going to have a patch that's at least double the size of what the Eterna Bond was covering...... Of course, there are applications where both would probably be OK and maybe even great, but I'd stick to the "OEM tried and proven" repairs for most applications.

[ajk170]

JRTJH - that's good advice - I've never used the spray flexseal too much nor have i had to remove it, so no idea how hard that is- but I like the point that the need to access the patched area should help drive a solution on how to best fix it. The eternabond example is a great example!