Community Forums

apopj · 06-18-2018, 11:27 AM

Don't want to reinvent the wheel, but was thinking of trying another way to seal vents on roof.

I know to clean the area around the opening very well to remove all of the old sealant. I know to run a strip of Butyl tape around the perimeter of the new vent. Now, Instead of putting the new vent into place, screwing it down, and applying a huge amount of Dicor to seal it, how about this....

Clean the area as usual. Apply the Butyl tape and put the vent into place. Now, push down on the vent to seat the Butyl tape. Using Eternabond tape, butt the tape up against the side of the vent and press it into place running over the edge and out onto the roof. Once all four sides are taped, run a bead of Dicor around the vent where the screw holes are (easily seen by the depression where the holes are in the vent surround). While the sealant is still wet, screw the vent down tight. This would seal the vent, and also seal the screw heads/holes. It would also be easier to reseal the vent at a later date as there would not be several pounds of Dicor and tape to remove.

I don't know if this is viable but thought I'd throw it out there. I know "we've always done it this way" the old way, but maybe there is room for a new way.

Thanks,

Dr. J Popa

BFlinn181 · 06-18-2018, 12:29 PM

I've never seen "several pounds of Dicor and tape to remove" a heat gun and plastic scraper can remove the old before putting on the new caulk.

The 'old' method has worked, remember the roof or the tank can move a bit and the vent opening is the place that can allow for that movement instead of ripping the vent pipe out of the tank below.

THenne1713 · 06-20-2018, 10:03 AM

I think (they) r talking 14x14 vent, u r talking plumbing vent? :-)

BFlinn181 · 06-20-2018, 10:24 AM

Quote:

Originally Posted by THenne1713

I think (they) r talking 14x14 vent, u r talking plumbing vent? :-)

Yes, I was thinking of tank vents through the roof, but I was mainly questioning the "several pounds of Dicor and tape to remove" statement. Most every item you'd fasten to your roof comes with installation instructions. I'd be very careful to modify or shortcut those instructions. I might add to them, but to do a different method could get very expensive if a leak develops.

ftodaro · 06-20-2018, 08:08 PM

Over the winter I stripped all the sealant (silicone) off my roof and resealed it using dicor. I sought advise from a local shop who is well respected in our area. His advice was that always stripping off the old is better than laying new over old. He also said the problem with the tape you mentioned is that it is difficult to remove, so if you plan on a re application then you may be making more work for yourself.

One thing is for sure, what you use to seal your roof is important. I used dicor, its common, its cheap, its easy to work with. I am not sure that it is the best thing out there but it does work and its not hard to strip and re apply.

So My point is doing dicor is not a bad choice, but it may not be the best either.

BFlinn181 · 06-20-2018, 08:30 PM

I agree with the Dicor, I've used it myself for all my RV roof needs. One of the reasons silicone is not recommended is that it always fails and leaves a residue that makes it difficult for anything else to bond to the silicone.

When I was a kid, silicone came on the market as the 20-year wonder caulk. Many folks used it on boats when I was growing up on the Chesapeake. It gathered dirt and failed within a year or so. Removing all the caulk was a major problem and caulk, paint, varnish, or anything else would not bond with the seams that had silicone applied. It was (and is) a mess waiting to happen. I really dislike the stuff. The only place I've ever seen it work is in aquariums.