Caulking around roof vents and ac unit

wa8yxm wrote:
Around vents and skylights. ... Dicor Lap Sealant (not the self leveling kind)...

:h

First off make sure you read your owner manual on the skylight. Some skylights will become brittle and crack if you use the wrong sealant. Second I don't understand why the vents can't use self leveling Dicor, that's pretty much what 99% of us use (that I bump into on the road) when it comes to caulking.

Around vents and skylights. Eternabond or Dicor Lap Sealant (not the self leveling kind)

Around air conditioner DO NOT CAULK!!!

There is a foam rubber gasket between the upper unit and the roof. Tighten the 4 bolts that go through the roof to the specified torque and it should not leak.

IF it does, remove the 4 bolts. and disconnect the wires that go to the top from the bottom (usually Molex plugs that only plug in one way) remove the top unit and the gasket and drop on another gasket.. Then replace.

Also, while top side (Even if not removing the upper unit) "pop the top" (Remove the shroud) and the inner covers and clean clean clean, Epically the condenser and evaporator coils and any path where water should flow (the plastic tray below the condenser) This will give you better A/C operation Also clean the inside filters. (Often)

Bob Landry wrote:

ken07734 wrote:
on this subject, can caulking the roof wrong stop the AC from working right?

No, why would it?

If the caulking interfers with the normal drains in the lower A/C pan that allow the condensate to naturally drain onto the roof and then off then you run the risk of "damming" the water between the caulking and the rubber A/C gasket and increasing the potential for a leak thru the gasket. I would advise against attempting to put any sort of caulking around the A/C.

Larry

ken07734 wrote:
on this subject, can caulking the roof wrong stop the AC from working right?

No, why would it?

on this subject, can caulking the roof wrong stop the AC from working right?

Mfar1234 wrote:
To make sure I understand ... before using the Enterbond tape one should clean all of the old caulk off first - right?

To do the very best job that is what I would recommend, but be advised it is VERY, VERY labor and time consuming. You can put it over the existing caulking, but the general problem is that you want at least 1 to 1 and 1/2 inch of non caulking area on each surface (flange and roof) for the Eternabond to adhere to. Most caulking jobs don't have that on the flange itself and this would reaquire only a 1" width of original caulking to be around the item with it only going about 1/2 inch onto the flange and onto the roof for a 4" width strip of Eternabond to get that overlap. Also, existing caulking needs to be smooth enough so the Eternabond won't "tent" on the virgin surfaces that you are trying to get it to adhere to. I removed every trace of existing caulking on my roof before sealing it in Eternabond, but IIRC it took a good 4 hours PER VENT to clean all the old caulk off and prep it for sealing with Eternabond.

Many folks don't go to the lengths I did, but I'm not sure how durable there applications over the existing caulking will actually be, but many seem to have had success.

Larry

To make sure I understand ... before using the Enterbond tape one should clean all of the old caulk off first - right?

I did what Billy W said. Run a 4" width of eternabond around the vents.
You are now done forever. I had an area that was missed with the dicor,
very small and it leaked quite a bit.
Brian

You don't caulk the A/C, if you have A leak just snug the bolts a little and if that doesn't do it, you change the gasket. :)

The air-conditioner has a special gasket and requires no caulking. Use Dicor self-leveling caulk for other roof vents.