What type of caulking?

camr

Well-known member
I have been doing some general maintenance on the trailer and noticed a few places where the caulking is pulling away and should be replaced before leaks start. But what type of caulking? I have seen the terms "silicone" and "acrylic" caulking used, but I have no idea what is appropriate. I assume one marked "exterior use" would be a good starting point. But here is where I may be over-thinking the issue. The caulking that Heartland used is relatively soft and easily removed. I can use my finger nail. It also didn't last very long. I have used silicone caulking in bathroom and tub applications in the past, and it is strong, yet always remains flexible. Silicone caulking also comes in a 30 year exterior variety. Why would I, or Heartland for that matter, not use an exterior silicone caulking? I understand it would be much more work to remove the silicone caulking, but for caulking around the trailer door, for instance, it seems far more appropriate to use a "permanent", yet flexible caulking like silicone. How often am I likely to have to remove the main door?
Can anyone with more maintenance experience enlighten me on what type of caulking to use, and if not 30 year exterior silicone, why not?
Thanks, Cam.
 

brianharrison

Well-known member
Take a look at this thread - the Heartland factory uses Sikaflex 521UV. The EPDM roof requires a Dicor lap sealant for caulking around the openings.

Hope this helps. There are many other threads on Caulking as well - use the search feature and you'll find lots.

Take care,
Brian
 

GOTTOYS

Well-known member
Silicon caulking in my experience, doesn't hold up well to UV. It also doesn't stick to rubber roofs very long if at all. After a short time it will shrink and you can peel it off like a long rubber band. The 30 year warranty only means they will replace the tube of caulk, no labor, no promise it will hold up that long. Once you apply silicon caulk nothing else will stick over it and it is hard to remove the residue. I have never seen silicon become a permanent caulk even when used around a bathtub, so there goes the 30 theory. Stick with the products the factory uses and you will have the best luck. If the silicon was that good they would use it. It's probably less expensive than the Dicor or Sikaflex. JMHO...Don
 

SJH

Past Washington Chapter Leaders
Take a look at this thread - the Heartland factory uses Sikaflex 521UV.

No ill intensions but I am getting ready to order some Sika products and I cannot find the 521 in their catalog. Heartland Customer Service told me 505UV and there is a 221 without the UV that could substitute. Both are a Polyurethane sealants and with the Big Country I need one that comes in gray. No one in our area carries Sika products so I need to mail order. Do you have a source for the 521?

Best Wishes!

EDIT - Found the 521 at a Marine Supply store. It is a SILANE-TERMINATED PREPLOYMER as opposed to the POLYISOCYANATE PREPOLYMER. Not sure what that means but they are different!
 

GOTTOYS

Well-known member
No ill intensions but I am getting ready to order some Sika products and I cannot find the 521 in their catalog. Heartland Customer Service told me 505UV and there is a 221 without the UV that could substitute. Both are a Polyurethane sealants and with the Big Country I need one that comes in gray. No one in our area carries Sika products so I need to mail order. Do you have a source for the 521?

Best Wishes!

EDIT - Found the 521 at a Marine Supply store. It is a SILANE-TERMINATED PREPLOYMER as opposed to the POLYISOCYANATE PREPOLYMER. Not sure what that means but they are different!

I have also used a product called Quad. It's a polyurethane caulk that is very popular in this area with siding contractors. Not sure which of the fancy names it has..I used it on two of my previous RVs on the siding and trim with very good success. It's priced on the higher end and is available in a gray as well as other colors. I found it at one of the big box Home centers. A friend of mine works there and said is very popular with contractors...Don
 

JohnDar

Prolifically Gabby Member
No ill intensions but I am getting ready to order some Sika products and I cannot find the 521 in their catalog. Heartland Customer Service told me 505UV and there is a 221 without the UV that could substitute. Both are a Polyurethane sealants and with the Big Country I need one that comes in gray. No one in our area carries Sika products so I need to mail order. Do you have a source for the 521?

Best Wishes!

EDIT - Found the 521 at a Marine Supply store. It is a SILANE-TERMINATED PREPLOYMER as opposed to the POLYISOCYANATE PREPOLYMER. Not sure what that means but they are different!

Silanes are a form of silicone compound,i.e., they contain silicon in the formulation. I picked up a tube of RV caulk at International RV to touch up my cap seams (the sides, not the roof), and it contains silicone. Not sure what the brand was, since it's in the rig and I'm not. But I was assured that it was the proper thing to use and it was next to the Dicor products. I'll post the brand name next week, when we're back at the rig.
 

brianharrison

Well-known member
The UV rating is the most important in my thoughts. That way they do not break down nor discolour exposed to the elements. The 505UV recommendation from Heartland customer service is important - maybe it supersedes 521UV.

Take care,
Brian
 

traveler44

Well-known member
I'm sure there are some folks who are going to say I'm wrong but I use 3M 5200 Marine caulk. It costs more but it is permanent and so far I don't see the mold problem that I saw with the less expensive caulks. I'm sure it can be removed if need be by cutting and scraping but for me I would rather do something once and not have to do it over again next year. I haven't needed to do the roof yet but when I do I will use whatever is recommended. Tom M.
 

robnmo

Well-known member
Interesting thread, I started replacing some 1 yr old caulking that had broken loose on the Cyclone with a silicone that we've been using for years for kitchen equipment installation in a popular steak house chain restaurant. Been told by the caulking company that it will outlast sikaflex for years and its UV safe so thought..........WHY NOT? So far so good but it's only been a year on some caulking joints so the jury is still out right now. This summer is going to be the true test between sikaflex and the one we're trying.
 

camr

Well-known member
I am very happy with how this thread is progressing and the thought processes that we are applying. One of the facts that I am having a hard time getting by is IF the Sika non-silicone product is superior, why is it barely lasting one year. The silicone products labeled as exterior state that they contain a UV inhibitor. I have used exterior silicone on our house, and 5 years later it has held up well. The temperature range has been from over 100F to -40F, on the south side. Hasn't yellowed or cracked. But my house does not have the vibration and movement of a trailer either. I can't imagine a more demanding caulking application than a marine setting, and exterior marine silicone seems like not only the obvious choice, but the only choice. I understand that one huge difference will be the ease of removing the non-silicone product later. I think that we can all agree with that point. So for the main door that I don't plan to remove on a regular basis, silicone, or marine silicone for that matter, seems like an ideal choice. But for an application that I want to remove the caulking from, maybe like an access port, I would love to find a "semi-easily removable" caulking that will last more than a year.
Maybe we can re-visit this tread a year from now, and robnmo and traveler44 can let us know how silicone and marine-silicone hold up. I have a stinkin' hunch that they will be under the awning with a cold beer while I am removing and re-caulking!!!
Thanks for everyone's thoughts and input. That's why this forum is the best.
Cam
 

cookie

Administrator
Staff member
There are no doubt several good caulking materials on the market. I don't want to get off the caulk subject here, but one thing that all caulking jobs need is good surface preparation. I have noticed that when I see caulking pulling away from a surface it is almost always pulling away from a plastic trim or a piece of extruded aluminum not the body. I think that when these pieces of trim work are made they use some sort of release agent, thus the caulk does not want to adhere properly. I always prep with mineral spirits and soap and water.
Just some thoughts.

Peace
Dave
 
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