Spray insulation/ductwork?

[stryped1]

I am wanting to convert my flex duct in my crawl space to metal duct. However, the duct at Lowes seems flimsy. I also am having in the summer condensation on my ductwork. I want to eliminate this.

Can I use the expanding spray can foam sealant or rubberized undercoating like you use on a car to spray the duct before installation, then wrap it with the duct wrap insulation to maximize the insulation value of the duct and to give the duct rigidity?

One last thing, can a person buy the professional spray insulation material and spray it themselves at home in the attic etc? I have a large air compressor and several spray guns? I would like to add some insulation myself, especially in the attic.

I really appreciate it!

[trader4]

I don't know how you'd control the expanding foam so as to not have a gigantic mess. And the rubberized stuff sounds like a big pain in the ass for little gain. I wouldn't re-invent the wheel. The Lowes material properly supported is probably fine. If you want heavier gauge, go to an HVAC supply and they should have it.

This might be a project where if it has to be done, hiring pros might be a better idea. I've done a little DIY duct work, but I wouldn't take on this myself. Having the right tools, equipment, shop to make up any necessary pieces, etc and the experience and this goes fast and you get a pro job. DIY for a typical redo of a whole crawlspace duct system, I would think is going to be a real pain in the ass and the finished product, not so good.

AFAIK, no. They have a truck with pumps, the material comes in 55 drums, I think it gets heated, run through a special gun that mixes it, etc.

[stryped1]

Part of what I want to do is make it where the insulation is "animal proof". I have cats that get under there for warmth and sometimes they claw at the insulation.

What I really wish I could find is something to slip over the ductwork like what they make for insulating pipes. (The black foam stuff.)

[trader4]

owever, the duct at Lowes seems flimsy. I also am having in the summer cond ensation on my ductwork. I want to eliminate this.

ng like you use on a car to spray the duct before installation, then wrap i t with the duct wrap insulation to maximize the insulation value of the duc t and to give the duct rigidity?

rial and spray it themselves at home in the attic etc? I have a large air c ompressor and several spray guns? I would like to add some insulation mysel f, especially in the attic.

f". I have cats that get under there for warmth and sometimes they claw at the insulation.

ke what they make for insulating pipes. (The black foam stuff.)

They nake aluminum foil faced insulation for that purpose. The aluminum foil faces out.

I would think that would probably be left alone by the cats. At least as much or more so than the black foam stuff.

Or how about obtaining a small shelter of some kind for the cats, maybe you could even find something on craigslist that someone wants to get rid of? Then keept them out of the crawlspace.

[clare]

For the ductwoek, you want STEEL dunt, not aluminum - it is stiffer. Then you want to put pipe wrap on it in a non-heated crawlspace - AFTER you seal all the joints - usually with aluminum duct sealing tape. No reason you couldn't spray the ductwork with bed-liner if you want to toughen it up.

That flex "duct" should be totally outlawed for ANY use.

[stryped1]

Any problem using bedliner material on it if the material says it is flammable?

[Arthur Conan Doyle]

Yes, but you aren't going to do it with a spray gun. One supplier I've used is TigerFoam:

It's not as easy as it looks and you can really screw up your house if you foam the wrong side of the vapor barrier, so you best be careful.