Insulating floor over unfinished basement.

[Tom The Great]

Hello Eveyone,

Looking for suggestions. I have an unfinished basement, with unfaced fiberglass insulation in between the floor joists. I hate the stuff. Anytime I add a circuit, soon I will be adding bridging, or just walking on the flooor, I get fiberglass on me, boxes, and in my air.

I will be removing the fiberglass to shore up a bouncy floor, I want to NOT put it back, and wondered what are my alternatives. I want insulation that won't be declared a hazard on a couple decades(yeah fiber glass is heading there). So after this ramble, can anyone offer a suggestion?

tom

[Eigenvector]

What about that denim/cotton insulation? I've heard that it's pretty decent stuff really, and it doesn't shed microscopic particles of irritating glass.

[Wayne Whitney]

I'm facing the same situation, and I've thought about it some, although I haven't decided on anything yet. Another poster suggested cotton batt insulation, which seems like a good idea and is one I'm considering. The other option I've thought of is to attach a small continuous angle bracket to the bottom of the sides of each joist and use this to support rigid insulation.

Cheers, Wayne

[Joseph Meehan]

I suggest removing it, doing all the work you need done, then putting it back in (why waste good insulation) then cover the whole thing with plastic or house wrap like Tyvek?

[Tom The Great]

I saw something like that on "this old house", now my memory serves me, they said it offered sound dampening properties above fiberglass because of its density. Might be an option, I have a 4 year old that jumps too much and an office in the basement. I wonder how 'readily' avalible this stuff is. Thanks for your suggestion.

tom @

[Tom The Great]

I have duct work, and wiring in joist area. Rigid seemed like it had to be 'cut' perfect, or lots of gaps could be an issue. I was thinking about a rail system close to the edge, and sliding the foam boards up like drop ceiling tiles. I have to now find a product that matches my imagination. So I can make comparisons.

thank you,

tom

[Tom The Great]

Can tyvek be left exposed? Serious question, since vapor barriors on insulation says they need to be covered with fire barrior. Just thinking out loud, will look this up. Thank you!!!!!!!

tom

[Joseph Meehan]

Good question. I had not thought of it as an inhabited space, but ... ??

[Wayne Whitney]

There are two makers of cotton insulation batts,

and For a discussion of the material, see

Cheers, Wayne

[Wayne Whitney]

If you are concerned with leaving tyvek exposed, then that would rule out rigid insulation, as I'm not aware of any that can be left exposed to an inhabited space.

Cheers, Wayne

[Tom The Great]

Good point, I thought the metal foil stuff was ok.

tom

[Wayne Whitney]

Oh, I don't know about that stuff. But I guess if you are treating the basement space as habitable, why insulate between it and the first floor? You could include the basement space in the thermal envelope and insulate its boundary.

Cheers, Wayne

[Joseph Meehan]

Tom The Great wrote: ..

I just did a little search and found this from DuPont:

1. Can DuPontT Tyvek® be used in attics? On roofs? Under Floors? On the interior?

In 2006 DuPont introduced Tyvek® AtticWrapT, a unique, breathable membrane that helps create an airtight seal to reduce air leakage and energy loss through the roof. All other DuPontT Tyvek® products in Canada and the US have been tested and approved as a product to be installed behind exterior walls.

[Tom The Great]

It's 'unfinished', meaning not insulated, and not heated(zero vents). It's typically 10 degrees colder than the house. So the house came with the floor joist area insulated, and made sense, I have warm floors.

As for habitable, washer dryer, work area and computer is down there. I tend to work with a jacket, and have not immediate plans to insulate or heat the space.

tom