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LK23 02-24-2020 09:59 PM

Should I replace silicone caulk with polyurethane caulk?
I have to remove and replace about 10 inches of Newmar applied silicone caulk. Should I replace with silicone or possibly polyurethane caulking.

Pros and cons?

I am interested in comments and suggestions.


photopilot 02-24-2020 10:36 PM

Do not use silicone. Use ProflexRV- a polyurethane flexible sealant. Silicone is a PITA to remove and nothing sticks to it, so youíll have to mechanically remove the old silicone. Plastic razor blades or plastic putty knives help.


LK23 02-24-2020 11:22 PM


I looked up ProflexRV and it looks like a much better product than silicone. And, likely easier to apply.


Newmar2856 02-25-2020 12:33 AM

Itís actually quite sticky and gets tacky fast, especially in warmer weather. I would suggest applying it in short lines and then using a finger dipped in warm water with a bit of dish soap to smooth it out. Masking lines with blue painters tape also helps. If you do use tape, pull it off once you smooth a section out. Donít let it get too dry or itís a bugger to remove.

Pine Stump 02-25-2020 07:41 AM

Use a toilet paper center and use the edge to remove the excess caulk that will flow to the inside and make a perfect bead as seen on RV Geeks..

oldmattb 02-25-2020 08:23 AM

I don't use silicone caulk on anything, anywhere.

Polyurethane caulk is great stuff. I use it for permanent joints, like on body panels, rebedding the electrical inlet, sealing around pipes and hoses in the belly. When cured, it is very difficult to remove. Generally paintable, and likes moisture.

I use latex for less demanding applications such as indoor panels, seal up a fiberglass crack I want to repair later, seal where interior wires exit the wall. It is easily removable and does not weather well when uncoated.

For bonding things, I like Goop (plumbers, shoe, etc.). It is the best for sticking things to things. In most cases it is a permanent bond - you will destroy wood, plastic, etc. trying to get them apart.

For roof seams and inlets, I like Dicor, or the equivalent approved for the roof type. It stays flexible, removes easily, and new sticks to old.

I was a landlord for 25 years, and I found that silicone caulk created more problems than it solved.

Matt B

Wizard 02-25-2020 08:23 AM


Originally Posted by Pine Stump (Post 5161236)
Use a toilet paper center and use the edge to remove the excess caulk that will flow to the inside and make a perfect bead as seen on RV Geeks..

Thanks for that tip. I've always hated caulking jobs. especially removing the excess. I'll sure be trying that next time.

GypsyR 02-25-2020 10:02 AM

I'm glad to see I'm not the only one who has soured on silicone in general. Makes you wonder though. Go into Home Depot and you're faced with like 40 kinds of silicone caulks and a few latexes on the sealants shelf. And that's about it. The only poly stuff they have are glues.

Dutch Star Don 02-25-2020 10:28 AM

I still use silicone and I think it works just fine. Over the years, someone trashes silicone because they installed it wrong or have a difficult time removing it and several jump on that band wagon. I want it to be tough to remove, that's why I'm using it. Silicone is not for every job and I think that's where people have issues. If I have a joint on the roof, where two flat surfaces meet, Proflex is a better choice. Silicone is not made to work well when joining two flat surfaces. When it comes to sealing a right angle joint or around the edges of a window, it works great. I replaced a fog window recently and used silicone. I taped off the area, applied the silicone and then pulled the tape. It worked perfectly and looks nice.

PetesMH 02-25-2020 10:58 AM

It is my opinion (FWIW!) that polyurethane is simply a better product for nearly all applications than silicone. Much like PEX is better than copper for plumbing and TPO is a better RV roof material than rubber or fiberglass. Sure the older products can still work fine and are familiar but times change and we should too.

davidceder 02-25-2020 02:47 PM

I am about to caulk the top of my shower walls as they have separated from the rig wall. I secured the walls near the top so they wont pull away. I think Newmar JUST depended on the caulking to hold the walls near the top. I was going to use silicon but it sounds like I should use Polyurathane. Is that the opinion here?


Johngflyer 02-26-2020 07:00 PM

Great book about Ace!11

LK23 02-26-2020 07:03 PM


LTC Ace Cozzalio will be inducted in the Army Aviation Hall of Fame at the 2020 Army Aviation Summit in Nashville on April 23, 2020. Very prestigious honor!!

Pine Stump 02-27-2020 10:07 AM

Being in the rubber business for 36 years prepping for the job is the most important part whatever u choose so make sure to clean area using acetone or rubbing alcohol..

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