Dicor removal

[Brantlyj]

How important is it to remove all the dicor from the roof membrane when installing a Maxair fan?

I can peel it off the metal flange of the vent easy enough but it’s stuck pretty good to the roof membrane. Kind of scared I’ll tear it.

[bobbecky]

I would remove what Dicor you need to be able to remove to old flange, install the new flange and add Dicor on top of the new flange as well as on top of the existing Dicor. No need to risk damage to the roof membrane. You might want to scrub the existing Dicor with soap and water before removing the flange so it's clean when you add new Dicor so it will bond well.

[Hblick48]

Originally Posted by bobbecky

I would remove what Dicor you need to be able to remove to old flange, install the new flange and add Dicor on top of the new flange as well as on top of the existing Dicor. No need to risk damage to the roof membrane. You might want to scrub the existing Dicor with soap and water before removing the flange so it's clean when you add new Dicor so it will bond well.

^^ x2. I've read that you can use acetone to clean roof and dicor in preparation to apply more.

[Brantlyj]

Originally Posted by bobbecky

I would remove what Dicor you need to be able to remove to old flange, install the new flange and add Dicor on top of the new flange as well as on top of the existing Dicor. No need to risk damage to the roof membrane. You might want to scrub the existing Dicor with soap and water before removing the flange so it's clean when you add new Dicor so it will bond well.

Thanks, that was my thinking also but I wanted to check with those that have done it before.

[chuckster57]

We use fantastik spray. If my brain is still engaged I remember you DONT want to use petroleum based cleaners on the roof membrane.

[Brantlyj]

Seems they used Dicor under the flange instead of the seal tape. So next question is do I have to get all that off? And how?

[Logan X]

If you have to remove it, I would try heating it up with a heat gun and using a plastic putty knife to scrape it off.

[Brantlyj]

The question is? Do I have to? Can I put the seal tape on the bottom of the flange and dope it up real good with new dicor?

[NH_Bulldog]

I know it’s more work, but it’s the difference between doing a good job as opposed to doing a crappy job. If it was mine, I would get all that old crud off and start fresh.

[sourdough]

Well, I guess they just popped open a couple of tubes of dicor, slathered a big gob around the edges, squashed the vent down into it and then put another tube on top of the vent flange.

Unless you get some really thick butyl tape to fill those gaps I'm not sure I wouldn't just go back and do what they did; put a large bead around the opening, squash the new vent flange down into it then cover the top of the flange with even more dicor. I'm thinking before you start that you might want to run in and buy some shares of dicor stock...you may cause a bump in their market price.

Also as Logan said, you could try to warm it up and see if you could peel it off realizing 1) you don't want to use too hot a heat, 2) the roofing is going to heat up too and 3) it may or may not want to come off...and it will be a slow process. I think I would try the heat on a small section to see if you can get it to work. It's going to make a lot nicer install if you can clean some of that up.

[Brantlyj]

Originally Posted by sourdough

Well, I guess they just popped open a couple of tubes of dicor, slathered a big gob around the edges, squashed the vent down into it and then put another tube on top of the vent flange.

Unless you get some really thick butyl tape to fill those gaps I'm not sure I wouldn't just go back and do what they did; put a large bead around the opening, squash the new vent flange down into it then cover the top of the flange with even more dicor. I'm thinking before you start that you might want to run in and buy some shares of dicor stock...you may cause a bump in their market price.

Also as Logan said, you could try to warm it up and see if you could peel it off realizing 1) you don't want to use too hot a heat, 2) the roofing is going to heat up too and 3) it may or may not want to come off...and it will be a slow process. I think I would try the heat on a small section to see if you can get it to work. It's going to make a lot nicer install if you can clean some of that up.

Well that’s pretty much what I did. I have a stack of razor blades. The kind you break off to get a new sharp end. Wore a welding glove so I could get a good grip and cut all the thick parts down as much as I dared.

Used the butyl tape and also a thin layer of dicor. Put the flange on and smooshed (that’s a technical term, look it up ), screwed it down and used the rest of the tube on top. I made sure it extended past the old.

After the first good rain I’ll take the fan top and the interior shroud and make sure there is no moisture but it Should be fine I think.

[rhagfo]

Well I replaced the rear vent on our 5er seven years ago. The original was set dry and then all screws and 3/4” to 1” of self leveling dicor was placed over it. I used a plastic scraper to remove most of the old dicor, then set the ne dry and sealed with dicor self leveling. No leaks!