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Old 09-22-2015, 08:13 PM   #1
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Replace caulking with silicone

My DW and I purchased our first RV this past June. It is a FW and the seams are sealed with silicone and some sort of caulking. I don't know why silicon was not used for all the seams.

My concern is that the caulking on the bottom of the cap is working its way out of the seams. I am assuming it is due to movement while traveling.

Is there a reason for not using silicon on all seams? If not, would it be a problem replacing the caulk with silicone? I am concerned that water will get into the seams.


2016 Crusader 295RST FW
2011 Toyota Tundra iForce 5.7 4.10 gears

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Old 09-22-2015, 08:48 PM   #2
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Normally seams are sealed with Dicor. Lots of people say silicone is bad with all thd UV.


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Old 09-22-2015, 08:54 PM   #3
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Dicor for the roof and proflex for everything else on the outside. Windows, doors side vents and some trim may have grey butyl inside the joint as an extra barrier.

Silicone will not adhere to itself. Once it tears away, you have to use a solvent to remove it completely which may damage the roof membrane.

Some rv shops use it because it guarantees them labour a year or two down the road.

Is it grey butyl putty that's coming out the sides of the cap? That's OK, it just means they used lots during assembly and some of it is oozing out with thermal expansion. Just tear it away.
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Old 09-22-2015, 08:59 PM   #4
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Newmar says to never use silicone seal as the primary sealant. They do use some over the windows to keep the main sealant from weathering so badly.
Our Magna uses urethane or Dicor depending on where it is. Urethane on all the awnings and Dicor on the roof. Not sure about the windows as I haven't needed to check them yet but it doesn't seem to be silicone.
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Old 09-23-2015, 07:24 AM   #5
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I want to thank everyone for the information provided. I will just remove what is oozing out and not mess with it.

Thanks again


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Old 09-27-2015, 03:11 PM   #6
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marcham, the caulking is grey so I took you advise and removed the excess.


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Old 09-28-2015, 05:01 AM   #7
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Never ever us silicone on an rv. Use Dicor anywhere that touchs the rubber roof and proflex down the sidewalls. Proflex is the best and if I had a fiberglass or aluminum roof I would us it up there as well.
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Old 09-28-2015, 06:25 AM   #8
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This year I covered all of the roof seams and, all roof top devises with eternabond tape on our class A. Best mod I have done to the unit. Will never have to worry about the roof leaking EVER. Great Product....
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Old 09-28-2015, 03:03 PM   #9
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Silicone caulk is a BIG No No on an RV!
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Old 09-28-2015, 05:18 PM   #10
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A lot of people recommend siliconing the tops and down the sides of windows about 1/3 of the length.

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ace, replace

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