Forum Discussion

kenkorona's avatar
kenkorona
Explorer
Sep 29, 2021

Roof sealant

I have to replace a skylight. I just received the replacement from the manufacturer. When I go to install the new one, what is the sealant? When I was on the roof, I saw the same white sealant used around every roof penetration. Somehow I recall the name dicor, but I'm not sure. When I looked Dicor up on Amazon, I see different kinds and in different formats (can or caulking tube). Can someone tell me what is the correct one to use? Or is it one of those "it depends..." things?

Ken
Truck Campers
  • d3500ram's avatar
    d3500ram
    Explorer III
    Sep 30, 2021
    I checked out the NuFlex 311 white sealant as suggested by member ronbiel as I had not heard of that brand before.
    https://www.amazon.com/Hengs-95502-White-NuFlex-Sealant/dp/B003YJNO98

    Seems like a respectable product, albeit quite a bit more costly! It is self-leveling which is what is good for a roof application. Do not use self-leveling on the sides of the RV... it might end up looking like it is owned by Salvador Dali (LOL.)

    Also- whatever you do...DO NOT USE SILICON SEALER!
  • Deb_and_Ed_M's avatar
    Deb_and_Ed_M
    Explorer II
    Sep 30, 2021
    d3500ram wrote:
    In my opinion, use butyl tape between the flange of the skylight and the roof. Then use Dicir Self Leveling (tube) to go over the assembly once it is installed.

    When you set the light (with the butyl tape) let it set overnight since the putty will tend to seep out. Once the oozing has subsided, then apply the Dicor.

    Use the self leveling because it will set up nice and even without needing to use a putty knife to monkey it around.


    This ^^^ is what I did when I swapped out a regular vent for a Fantastic Fan - the butyl tape/Dicor lap sealant are a great duo (and the Dicor self-leveling ends up looking smooth). Last year I removed a canoe rack from the roof of my 20-yr old pop-up TC. It had been installed the same way: butyl and Dicor. After 20 years, both were still flexible, tightly-sealed (and a PITA to remove....LOL!)
  • jimh406's avatar
    jimh406
    Explorer III
    Sep 29, 2021
    Dicor is what goes around the edge and screws. Butyl tape under, usually.
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Sep 29, 2021
    Be generous with butyl tape. You can always scrape the excess.
    No other treatment necessary and caulking is not lasting on TC.
  • d3500ram's avatar
    d3500ram
    Explorer III
    Sep 29, 2021
    In my opinion, use butyl tape between the flange of the skylight and the roof. Then use Dicir Self Leveling (tube) to go over the assembly once it is installed.

    When you set the light (with the butyl tape) let it set overnight since the putty will tend to seep out. Once the oozing has subsided, then apply the Dicor.

    Use the self leveling because it will set up nice and even without needing to use a putty knife to monkey it around.

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