Filling holes in roof - Page 2

pbansen · 10-20-2017, 02:01 PM

What diameter are the holes? You can get plastic plugs of various sizes from McMaster-Carr and other vendors.

I have used 3/4" rubber 'mushroom' plugs to fill holes punched for antennae on fire service vehicles - they'd be available from a communications supplier like Tessco. Put a little smear of silicone or Shoe Goo on the underside of the head, press the mushroom plug into place and never give it another thought. Never had a leak or a rust issue and they look factory.

It's not the end of the world to plug/repair the holes, but it's disappointing that neither the dealer nor inspector looked closely enought to notice the sketchy 'repair'...

brp · 10-20-2017, 02:48 PM

Just a heads-up that Shoe Goo is not UV stable, I think you can paint over it though.
Dicor seems to be a highly regarded product, and is UV stable. I have not used it.

pbansen · 10-20-2017, 03:49 PM

Quote:

Originally Posted by brp

Just a heads-up that Shoe Goo is not UV stable, I think you can paint over it though.
Dicor seems to be a highly regarded product, and is UV stable. I have not used it.

My suggestion to use Shoe Goo was just to seal and glue the plug into the hole and provide some additional peace of mind over the mechanical, interference fit - the Shoe Goo would never see the light of day, as it were.

Dicor makes a bunch of different products, notably a "non-sagging" caulk and a "self-leveling" product that seem to be quite popular in the RV community. The non-sag stuff works like traditional caulking that you would apply, smooth and allow to set up. The self-leveling stuff is runnier and kind of pools and puddles before it eventually hardens. The non-sag product is super sticky and - I thought - very hard to achieve a nice finish. The self-leveling product - at least in my case - was better, but was kind of inconsistent in how much it self-leveled. Some areas were great and came out really well, other seemed to skin over and stop 'levelling' before I would have liked them too. It's probably an acquired skill.

For filling holes, the non-sag product would be the best choice: the self-levelling stuff would run right through the holes and make a mess.

brp · 10-20-2017, 05:45 PM

Thanks for the clarification Pb. Are you happy with the performance of the Dicor product besides the finished look? I'm thinking of using Dicor 501 for installing a vent/fan and an intake/chimney for a Dickinson Newport propane heater. Thanks again.

ColoRockiesFan · 10-20-2017, 06:00 PM

Quote:

Originally Posted by pbansen

What diameter are the holes? You can get plastic plugs of various sizes from McMaster-Carr and other vendors.

I have used 3/4" rubber 'mushroom' plugs to fill holes punched for antennae on fire service vehicles - they'd be available from a communications supplier like Tessco. Put a little smear of silicone or Shoe Goo on the underside of the head, press the mushroom plug into place and never give it another thought. Never had a leak or a rust issue and they look factory.

It's not the end of the world to plug/repair the holes, but it's disappointing that neither the dealer nor inspector looked closely enought to notice the sketchy 'repair'...

I think plugs were used to fill the holes but it is hard to tell as some sort of unidentifyable substance was used to seal the plugs in place. As the roof heats up, the "substance" expands and grows into a fungus shape which can easily be seen.

Fortunately, I have ordered a fiberglass high top so that the issue will be moot in a couple of weeks!

moorefc · 10-20-2017, 07:07 PM

you are already getting a new roof, but replacing the silicone with 3M 5200 would be a soft, but permanent fix. Very sticky stuff, and the other suggestions are good, but that stuff seals boat underwater holes and is next to impossible to remove....
Something for the goop lovers

pbansen · 10-20-2017, 07:30 PM

Quote:

Originally Posted by brp

Thanks for the clarification Pb. Are you happy with the performance of the Dicor product besides the finished look? I'm thinking of using Dicor 501 for installing a vent/fan and an intake/chimney for a Dickinson Newport propane heater. Thanks again.

I think maybe it just takes practice to get the Dicor product to work as intended. Are your units going in on a relatively flat roof, i.e. not straddling any ribs? If the height difference is just the height of the flange for the vent/fan, the self-leveling goop should work well to seal the screw heads and provide a seal around the outside of the flange/roof interface.

I used a butyl putty tape between the flange of the fan I was installing and the mounting surface and that seemed to work well. Not sure if I really needed to use as much of the Dicor non-sagging caulk as I did, but my fan was straddling a rib and was mounted between two others and the adapter was about 1/2" high, so I tried to coat the outside of the adapter with the non-sag and then get the self-levelling stuff to seal the screw heads on top of the fan flange and then run down over the sides and seal around the base of the adapter as well. The result is not pretty, but I'm confident about the water-tightness - have to resist the temptation to scrape off all the Dicor and try it again.
Pete

pbansen · 10-20-2017, 07:33 PM

Quote:

Originally Posted by ColoRockiesFan

I think plugs were used to fill the holes but it is hard to tell as some sort of unidentifyable substance was used to seal the plugs in place. As the roof heats up, the "substance" expands and grows into a fungus shape which can easily be seen.

Fortunately, I have ordered a fiberglass high top so that the issue will be moot in a couple of weeks!

Sounds like you're snatching victory from the jaws of defeat! I'll try to find a picture of the plugs I mentioned - they look totally sano: no fungus look!

Pete