Forum Discussion

qtla9111's avatar
qtla9111
Nomad
Mar 12, 2014

Fantastic Fan Install - UPDATE

I am replacing an existing vent fan with a Fantastic Fan. My question is:

Do I need to use butyl tape for the install? A quick response would be nice. It's a sunny day today and great weather to be up on the roof.

Thanks in advance.

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I contacted Fantastic Vent and the tech said they no longer include a seal, too many people would use the seal and then not caulk and complained of leaks.

They recommend using Dicor 1/2 inch from the lip of the cut in the roof where the fan goes. Then, drill, fill, and cover with Dicor and then go around the outside edge.

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Thanks for everyone's contribution. I will show a pic when I am done. BTW, I'm not a DIY guy but there is always a time to learn.

8 Replies

  • Almot's avatar
    Almot
    Explorer III
    Mar 12, 2014
    To ensure a good adhesion of Dicor and other sealants on EPDM roof, you have to clean it VERY well, before applying a sealant. On the photo it doesn't look like you did - I don't see brighter/whiter areas on that gray background. In addition to dust and other contaminants, EPDM roof is in constant process of oxidizing and shedding the paint. These small particles of dead paint need to be removed with Ethanol or Acetone, before sealing.
  • qtla9111's avatar
    qtla9111
    Nomad
    Mar 12, 2014
    Wasn't so bad. I did it in a couple of hours. I had to run into town for a new drill bit and to cut the inner plastic shroud. Randu, I filled the holes and also gooped the screws before putting them in. I applied the Dicor the same way it was done from the factory, overlapping from the screws to the edge and then working around the edge. Not much to look at but let me know if the Dicor is sufficient. Works great with my solar.

    Thanks for all the tips.



  • bobmacc's avatar
    bobmacc
    Explorer
    Mar 12, 2014
    mrekim wrote:
    I was just checking out how to do this last night. Most of the installs I saw did this:

    a) Clean up area to be sealed.

    b) Butyl tape under the flange - ensuring the holes are covered.

    c) Dicor self leveling sealant around the flange and over the screw tops.

    If it's a rubber roof you need to make sure you use materials that are compatible. I think TPO and EPDM may even have different requirements.


    +1 You need to use tape and caulking.
  • Randu's avatar
    Randu
    Explorer
    Mar 12, 2014
    I'm thinking use the Dicor as its formulated to be compatible with roof. I would position vent and secure with a screw on each side so it won't move. I would then drill all remaining mounting holes. Remove vent and lay a bead of Dicor just inside of the holes. Secure vent with all screws. Bead will squish out forming a very nice seal as you tighten screws. More Dicor around screw heads and vent flange side. Finished ! Randu
  • mrekim's avatar
    mrekim
    Explorer
    Mar 12, 2014
    I was just checking out how to do this last night. Most of the installs I saw did this:

    a) Clean up area to be sealed.

    b) Butyl tape under the flange - ensuring the holes are covered.

    c) Dicor self leveling sealant around the flange and over the screw tops.

    If it's a rubber roof you need to make sure you use materials that are compatible. I think TPO and EPDM may even have different requirements.
  • qtla9111's avatar
    qtla9111
    Nomad
    Mar 12, 2014
    I have three tubes of Dicor for sealing but I saw a DIY video and the guy used buytl tape as a seal. So I can do this with just the Dicor caulk?
  • BoonHauler's avatar
    BoonHauler
    Explorer
    Mar 12, 2014
    qtla9111 wrote:
    I am replacing an existing vent fan with a Fantastic Fan. My question is:

    Do I need to use butyl tape for the install? A quick response would be nice. It's a sunny day today and great weather to be up on the roof.

    Thanks in advance.


    You need to use some sort of sealant, butyl tape, putty tape, silicone, etc.

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