are there register gaskets?

[grilleguy]

I'm a homeowner. I notice if any of my air conditioning vents (I guess that is the name of those metal covers that stick on the wall/ceiling over the opening to the a/c ducts, that have metal vents on them that you can open or close to let more air out or not) are not flush to the wall/ceiling/floor then the air will escape under the edges of the register and can form mold (cool air and some condensation). Not wanting that, I thought maybe I can go (somewhere) and get some sort of gasket that will provide a better seal between the wall and the register.

Is there such a thing as a register gasket and are they good ideas to use? Can I get them at my big orange box? If they aren't a good idea (or if they don't exist), what is a better way of making a tigher seal between the wall/ceiling and the register? Thanks.

I also have one duct that has a piece of sheetmetal that sticks to far out of the ceiling and I was thinking of cutting it down a bit. Is that a good or bad idea?

[41gasman]

Most all wall/ceiling grills have
a seal on them from the factory.
But if yours are toast or gone
then the box store should have
some kind of 3/16" to 1/4"thick
mushy gasket seal that you would
find in there weather sealing
kinda dept. More inportant than
the seal between the grill and
ceiling though is the seal between
the register boot and the ceiling!
Buy some of the silver tape that
has the wax paper between each
layer of tape(the good stuff).
And put it from the inside of
the boot to the ceiling.The
condisation you are talking about
is most likely from outside
air being drawn in around
the gap between the boot
and wallboard.Good luck.
41Gasman

[tinner73]

latex caulk and a wet sponge. gasman i know what your thinking Hart & Cooley have a bead of caulk in the back of their registers. i'm thinking that tape gasket is gonna keep it off the drywall too much.

[Edited by tinner73 on 02-19-2005 at 05:14 PM]

[coolguysfl]

Mr Grilleguy.
Two items:

If the gaps you describe at the cieling are cosmetic (IE: uneven plaster surface), caulk is what you need.

If the gaps are venting air from the attic, caulk is not the answer. Sealing w/ caulk around the grille is only cosmetic, the boot or duct assembly should be sealed (preferably from the top side) with mastic. Mastic is a flexible rubberized cement that is brushed on. It is important that the insulation be sealed to the cieling to prevent condensation. If the gaps are allowed to be open, the air coming out of the grilles causes a venturi effect sucking in dirty, damp attic air -

Many ultilities provide blower door testing to document the integrity of your homes sealing. Some contractors can also provide this service.

[maxster]

take a piece of cardboard and cut out the register opening and the size of the grill frame,get a sheet of thin rubber and trace out the grill in hand to be sealed.put the rubber cut out on the opening...re-install grill on top of that and screw it in...judge the thickness of the rubber to buy to fit the gap.also a sheet of styrofoam from packings or just plain old cardbord...roll of armaflex tape 1" wide,box the opening with it once around and install the grill!

[grilleguy]

Let's see if I understand what you all are saying:

Where the duct is connected to the wall or ceiling, there should be no gaps (such that I could see behind the duct work into the wall or ceiling). A way to solve that is to use duct tape from inside the duct to wall/ceiling surface to insure that there are no air gaps. Solid metal/tape to the wall. If that isn't sealed off properly then dirty air can be drawn into the duct. Do I have that correctly?

As to the grille touching the wall, I can either find a gasket at my big orange or blue box stores, or I can caulk the grille in place. I have never heard of caulking a grille in place (but that doesn't mean it isn't true). I would think when taking the grille off (to clean or replace it) that it would ruin the drywall. But maybe that isn't true?

Did I get that all correctly?

As to the grilles coming packaged with a gasket, I have never experienced that to be true.

Thanks for the advice!

[coolguysfl]

Caulking is just a cosmetic issue and on rare occasions with uneven texture cielings it is done. Yes, it impeads future removal.

Yes - you have it corrrect. Thier should be no air gaps from the attic into the homes penetration. If you have to seal the boot from the home side, tape, mastic, caulk will do. Again, best results will be sealing the duct penetration from the top (outside) side. Tapes often fall off from the heat drying them out. I would not use styrofoam to plug holes, it does not meet the flame & smoke ratings for duct work.

[maxster]

put in "air register sealing" in http://www.altavista.com for articals and solutions on this problem here is one of the articals http://oikos.com/library/airsealing/air_leakage.html

[grilleguy]

I think I am going to try sealing with the expensive silver tape from inside the sheet metal boot to just outside the opening onto the drywall (but staying underneath the perimeter of the grille). Maybe doing the mastic from the inside of the attic or wall or floor is the best way, but it sure would be the harder way. Who wants to go digging through insulation while standing on top of the joists? Not me.

I guess I will go to the big orange or blue box and get me some of the good expensive silver tape and give it a try on an out of the way opening. I know that getting that tape off in the future would not do the drywall any good, but if the taping is beneficial and if I buy the correct tape (is there some name or rating to this tape) then maybe I won't ever want to remove the tape.

If it works out, I try to will write back and let you know how it went. Thanks.

ps - I called up the company that handles my a/c / heating, and the gentleman I talked to had never heard of such a problem - in fact he had a hard time imagining it. I guess he never has looked under any grilles in the 15 years that he has been there as I can barely imagine a house built where the builder cared enough to do it correctly.

pss - Any idea how much a difference this can make? Like might there be less dust inside the house, or less mold near the grilles, or more pressure in the house, or just not that much difference one way or another?

[framehvac]

Yes it is call Caulking you make your owen gasket.