Caulking question

[Naio]

Another day, another noob question :B

My van had an INCIDENT a few days ago. A friend was driving it and managed to wedge it under the porch roof of a church!

Got home and told me the whole long hilarious story involving a 300lb pastor standing on the bumper to bring the van down so friend could back out, pastor getting showered with plaster, whole congregation watching..

Anyway, the van is basically fine, other than scratches on roof, one corner of roof not quite the shape it used to be, and some 12" cracks in the (new) caulking where fiberglass roof was joined to the van.

My question:

Since the caulking was done only a few months ago, can I just clean its surface and recoat it? The guy who did the roof install used Alex Plus caulk. Do y'all hate that? I sure hope you are not going to tell me I have to scrape it out and redo...

[Naio]

I called Geocel tech support. They said Proflex RV will probably stick to the Alex, to do a test spot, and if there is a problem it will 'alligator' within a minute or two. FYI in case anyone else wants to know :).

[jplante4]

Naio wrote:
Should I use the same stuff around the fan I am installing? Today is sealants buying day 🙂

Get some butyl tape to bed the fan flange and seal the penetrations with Dicor.

[drsteve]

westend wrote:
Siliconized latex caulk is not the caulk to use. I'd suggest to buy some 3M caulk remover and remove the Alex Plus. That will also allow you to see if the fiberglass is cracked (a real possibility). If the fiberglass is cracked, you will want to patch that with resin and fiber or just resin. Caulk will not hold it together for long.

The best caulk to use on the exterior is one of the polymer sealants made by Geocel. They are engineered for the transportation industry. Tripolymer 2300 adhesive and Proflex RV are two types of sealant made by Geocel.

X2.

Alex Plus is good for windows and doors on the sticks and bricks, and it's cheap, but it's probably not up to the constant flexing of an RV.

[Naio]

Should I use the same stuff around the fan I am installing? Today is sealants buying day 🙂

[Naio]

Thank you, westend!

Do you have experience with those products sticking well to the Alex? Or should I call the manufacturer and ask?

It's the bottom edge of the raised roof, in the gutter, so it gets ALL the water.

[westend]

Naio wrote:

westend wrote:
Siliconized latex caulk is not the caulk to use. I'd suggest to buy some 3M caulk remover and remove the Alex Plus. That will also allow you to see if the fiberglass is cracked (a real possibility). If the fiberglass is cracked, you will want to patch that with resin and fiber or just resin. Caulk will not hold it together for long.

The best caulk to use on the exterior is one of the polymer sealants made by Geocel. They are engineered for the transportation industry. Tripolymer 2300 adhesive and Proflex RV are two types of sealant made by Geocel.

This caulk is in the seam holding the roof onto the van. I could not remove all the caulk without removing the roof. If I remove the roof, I will not be able to do the van build this year. I would have to rebuild my old van (now gutted) and use it again this winter, find a place to store the maple flooring and other matierials I bought while I am gone, etc., etc.

I will do it if it absolutely has to be done, but it will destroy all my plans for the coming year.

As an alternative, is there a better caulk that would stick to the Alex Plus, that I could use as a top coat?

I will look again, but I can see all but the bottom half inch of the fiberglass roof, and I do not think there are any cracks.

Here's the deal: Silicone (or siliconized latex) is not a bad sealant when in compression, i.e. when located between two facing materials. Silicone deteriorates rapidly when exposed to the Sun and weather. Alex Plus is siliconized latex house caulk and typically lasts for 10 years when topcoated with latex paint. It will become brittle and shrink during that time. That is why, we, as house painters, spend inordinate time scraping old Alex Plus out of joints and applying a fresh bead. It is also the cheapest caulk available.

Here's what I'd suggest: Mechanically remove most of the Alex Plus that is around the joint. As a final cleanup, wipe down with mineral spirits. Inspect the fiberglass that is now exposed. After inspection and possible repair, apply one of those Geocel sealants. Doing it as above won't necessitate removing the top.

In the future--no silicone or latex on any RV exterior.

[Naio]

westend wrote:
Siliconized latex caulk is not the caulk to use. I'd suggest to buy some 3M caulk remover and remove the Alex Plus. That will also allow you to see if the fiberglass is cracked (a real possibility). If the fiberglass is cracked, you will want to patch that with resin and fiber or just resin. Caulk will not hold it together for long.

The best caulk to use on the exterior is one of the polymer sealants made by Geocel. They are engineered for the transportation industry. Tripolymer 2300 adhesive and Proflex RV are two types of sealant made by Geocel.

This caulk is in the seam holding the roof onto the van. I could not remove all the caulk without removing the roof. If I remove the roof, I will not be able to do the van build this year. I would have to rebuild my old van (now gutted) and use it again this winter, find a place to store the maple flooring and other matierials I bought while I am gone, etc., etc.

I will do it if it absolutely has to be done, but it will destroy all my plans for the coming year.

As an alternative, is there a better caulk that would stick to the Alex Plus, that I could use as a top coat?

I will look again, but I can see all but the bottom half inch of the fiberglass roof, and I do not think there are any cracks.

[Naio]

kerrlakeRoo wrote:
Naio,,,, didn't you know your clearance? :h

I wasn't there!

[westend]

Siliconized latex caulk is not the caulk to use. I'd suggest to buy some 3M caulk remover and remove the Alex Plus. That will also allow you to see if the fiberglass is cracked (a real possibility). If the fiberglass is cracked, you will want to patch that with resin and fiber or just resin. Caulk will not hold it together for long.

The best caulk to use on the exterior is one of the polymer sealants made by Geocel. They are engineered for the transportation industry. Tripolymer 2300 adhesive and Proflex RV are two types of sealant made by Geocel.

[Charlie_D_]

I refuse to use a latex caulk on anything associated with my camper. Goes against everything I have read on this and several other forums and manufacturers websites.

[jplante4]

darsben1 wrote:
If you are cleaning out the area then I would go with either Dicor tape or. Eternabond caulking. Both are the tried and true RV caulks

That's Dicor caulk and Eternabond tape.

[folivier]

Tell him next time to let some air out of the tires....

[darsben1]

If you are cleaning out the area then I would go with either Dicor tape or. Eternabond caulking. Both are the tried and true RV caulks

[STBRetired]

Used that caulk on my house 8 years ago. Is still rubbery even where it gets a lot of sun. Hope it holds up as well on your van.