Leaky air ducts in crawl space, how to tackle?

[hoosierdoc]

When I went in to shut off water at the mother-in-law's place I noted the air to be frigid and a positive air flow. It was hot out and AC was on.

I don't want to spend a lot of time down there but want to make it better before winter heating season. What should I bring with me to patch holes or resecure things? I've heard rumors home depot rented FLIR cameras which would make finding the leaks much easier but can't find that online.

 

[Mr. Habib]

IMO the first step would be to seal all of the joints, and any obvious holes with aluminum tape, NOT duct tape. Step two would be to insulate the ducts, if they aren't already.

 

[hoosierdoc]

IMO the first step would be to seal all of the joints, and any obvious holes with aluminum tape, .

I've seen the shiny metal stuff on my runs before. I had planned to bring a good supply of that. It's hard to get in/out of and I want to have it all on hand. Can you splice those things together if one is really tore up?

 

[Brandon]

Is it the metal duct work or is it the flexible ducting?

 

[hoosierdoc]

I believe metal. It's probably 40+ years old

 

[cbseniour]

Duct tape, that's what it's made for

 

[Rookie]

Metal tape should be all you need unless there's missing duct.

 

[Brandon]

There is a kind of paste and I don't know what it is called, to help seal up small holes and leaks. Then use the real duct tape *foil tape* to seal everything up as good as possible.

Edit: This stuff
http://www.theenergyconscious.com/wea2105.html?gclid=COXP3OiRnbMCFVBgMgod52sArw

 

[Rookie]

Duct tape, that's what it's made for

Won't last as long as metal tape.

 

[Rookie]

I'm guessing some duct work is falling apart. Get a tote, put some bailing wire, 1/2inch sheet metal screws, 1inch sheet metal screws, metal tape, and drill in it. Use the 1/2inch screws to put the ductwork back together, use the 1inch screws and wire to brace it, use the tape on the seams.

 

[Rookie]

If it's really nasty, take a roll of plastic with you and unroll as you go. Use the roll as a headrest. Don't unroll until you need to or it will just get nasty.

 

[Rookie]

Oh yeah, don't forget something to cut the wire

 

[femurphy77]

Make repairs as necessary to the structure of the ducitng then have spray in foam insulation blown over all of the ducting. Seals it nicely the added insulation is a plus!

 

[jeremy]

Spray foam....

 

[LtScott14]

+Rookie. Have a few options and a buddy/wife/gf to help send things down to you. Wear a headlight and a baseball cap( keep spider webs away from your face) if its a real low crawl, get a helper to jump in the hole with you! Beer and pizza afterwords is good for some laughs. If the metal is really shot, you may need some professional help. Where is your HVAC /hunting buddy when you need his help?
A loose duct can cause your house to be cooler than usual. If it is flex, you can replace it pretty easily, but I would do a few rooms at a time. You will need to take a break for your knees and back to keep working. Good luck.

 

[danimal]

Duct tape, that's what it's made for

Just say NO to duct tape

I know because the idiots used it at my house, and it has done exactly that; brittle and peeling off. All the new runs in the basement that I did, used foil tape and something flat and soft to rub as much of the creases out as you can.

You can also find the mastic paste in caulk gun tubes at Home Depot for about $4 a tube, shouldn't need more than 1, they cover quite a bit. It's water based, so you can squeeze some out onto your finger tip and rub in onto the joint (careful of sharp metal edges). Allow it to set for about a 1/2 hour, then foil tape over, smoothing out the creases.

Spray foam is the best, just depends on how much you're looking at spending on this endeavor.

 

[churchmouse]

Before any adhesive will bond with the "Old" duct if metal or fiber you must clean the area with some kind of solvent. We have been forced to use scotch brite and brake clean to get the crud off the old duct before the tape will stick and "STAY" in place. Do a test on the duct close to the crawl entrance and see what you are up against. If the duct has fallen down it will have to put back into it's original position and fit back together. Support is all important. If you have issues PM me. Will help if we can.

No duct tape. It is not permanent in that environment.

 

[Bunnykid68]

Duct tape is not good for duct work. Use the foil tape. Any heating/ac guy will tell you the same

 

[warangelcometh]

I used HD Duct tape on all my joints and caulked and foam insulated underneath the floor registers. Sealed the system up great.

 

[heatman]

You want to use mastic caulk made for HVAC systems. You can buy it in caulk tubes or the best way is to buy it in a bucket and simply use stiff paint brush to apply it. They have water and solvent based mastic. Water based is easier to use and easier cleanup if you get it on you.