vapor barrier location w/insulation

[Cheeky]

i'm getting rid of the fiberglass insulation in my basement ceiling. replacing it with denim (this stuff rocks btw...no itch, and ok on the lungs).

so it will go in between the joists. is there a need for a vapor barrier? if so, does it go below or above the insulation?

the denim isn't paper-backed.

[iceman61]

I have to chime in here

The vapor barrier on insulation is always installed towards the living space. The moisture is coming from your heat. A vapor barrier is designed to keep moisture that is in your home from getting inside your walls, much like the condensation that can occur on the inside of your windows on a cold day.

The vapor barrier on wall insulation should always be stapled on front of the studs & not to the sides of the stud. This creates more of a seal after you tack up the wallboard.

In the attic, it's not as important to attach & seal the vapor barrier since your attic is supposed to have proper ventilation. Some people think that building wrap is a vapor barrier but it is actually designed to let your walls breath to the outside thus letting your insulation breath.

If your basement is finished you won't need a vapor barrier in the ceiling. You only need a vapor barrier in a basement if there is alot of moisture. If it is under a house as in a crawl space, a vapor barrier should be installed directly on the ground & not on the bottom of floor joists.

Hope this helps

[lkazista]

IN actuality, if your basement is heated, then you should remove the ceiling insulation, and NOT replace it. You really do not want to isolate the two spaces from one another if they will both be climate controlled.

May I ask why you with bother with removing the fiberglass? Why not just seal it in with ceiling pieces? Any finishing job will be easier than ripping out fiberglass and stuffing it into garbage bags.

Lee

[Cheeky]

May I ask why you with bother with removing the fiberglass? Why not just seal it in with ceiling pieces? Any finishing job will be easier than ripping out fiberglass and stuffing it into garbage bags.

Lee

i'm replacing it because I received quite a bit of the denim for free. secondly, i found someplace that will recycle the glass (for boating purposes I believe).

i would seal it in, but fiberglass cannot be sealed 100%.

[Tom Slick]

here is the material's website, it has a little insight.
http://www.bondedlogic.com/installation.htm

I only use the denim material when I do projects now, much less hassle and better performance.

[JimD]

In the southeast, they do not put a vapor barrier in walls toward the living space as is recommended in the north, because in the long summer time the humidity is high and the moisture could move into the wall and condense against the vapor barrier. Around here, they do not use a vapor barrier.

Insulation in the ceiling can help with sound transmission even if both spaces are heated and cooled.

Jim

[gerti]

Rule of thumb (AFAIK): moisture barrier should be on the 'warm' side. If it were on the cold side, warm air would condensate on the moisture barrier and create problems. That is why in Minnesota we rebuild our houses every spring and fall...

[jackellis]

We're designing a house that will be built in the California mountains (elev 6000) using spray foam insulation. Three reasons: 1) higher R-Value so lower energy use, 2) little or no air infiltration, so no drafts, 3) 1 and 2 allow a smaller heating plant. The idea is to minimize energy use in wintertime, even though we expect to get the bulk of our heat from a wood stove.

Fiberglass is cheap but it's not the best choice IMHO for colder climates because it becomes less effective as temperature drops, it becomes less effective with age (sags and droops) and it leaks air. Denim, cellulose and other loose fill insulations have the same drawbacks, although to a lesser degree. If you're going to put in new insulation anyway, you ought to put in the best stuff you can while you can. I wish we could to that in our current house, which is uncomfortable in our (short) winters despite the relatively mild climate.

Foam has a higher initial cost but if you think you're spending a lot to heat your home now, you ain't seen nothin' yet. We're not running out of energy, but the demand for it around the world is going to continue to drive the price up. The payback is probably about 15 years at current prices.

[Cheeky]

We're designing a house that will be built in the California mountains (elev 6000) using spray foam insulation. Three reasons: 1) higher R-Value so lower energy use, 2) little or no air infiltration, so no drafts, 3) 1 and 2 allow a smaller heating plant. The idea is to minimize energy use in wintertime, even though we expect to get the bulk of our heat from a wood stove.

Fiberglass is cheap but it's not the best choice IMHO for colder climates because it becomes less effective as temperature drops, it becomes less effective with age (sags and droops) and it leaks air. Denim, cellulose and other loose fill insulations have the same drawbacks, although to a lesser degree. If you're going to put in new insulation anyway, you ought to put in the best stuff you can while you can. I wish we could to that in our current house, which is uncomfortable in our (short) winters despite the relatively mild climate.

Foam has a higher initial cost but if you think you're spending a lot to heat your home now, you ain't seen nothin' yet. We're not running out of energy, but the demand for it around the world is going to continue to drive the price up. The payback is probably about 15 years at current prices.

the spray foam is just impractical for the basement application. i totally agree with the expanding foam's superiority, but considering the pipes and electrical are run through the joists, it would be too much of a hassle.

I'm having somebody come out in the spring, to spray the garage walls and ceiling (there's a cold bedroom over it) and some parts of the attic. I've decided to go with the soy product, seems like the least harmful method.

[Garasaki]

We're designing a house that will be built in the California mountains (elev 6000) using spray foam insulation. Three reasons: 1) higher R-Value so lower energy use, 2) little or no air infiltration, so no drafts, 3) 1 and 2 allow a smaller heating plant. The idea is to minimize energy use in wintertime, even though we expect to get the bulk of our heat from a wood stove.

Fiberglass is cheap but it's not the best choice IMHO for colder climates because it becomes less effective as temperature drops, it becomes less effective with age (sags and droops) and it leaks air. Denim, cellulose and other loose fill insulations have the same drawbacks, although to a lesser degree. If you're going to put in new insulation anyway, you ought to put in the best stuff you can while you can. I wish we could to that in our current house, which is uncomfortable in our (short) winters despite the relatively mild climate.

Foam has a higher initial cost but if you think you're spending a lot to heat your home now, you ain't seen nothin' yet. We're not running out of energy, but the demand for it around the world is going to continue to drive the price up. The payback is probably about 15 years at current prices.

How you gettin fresh air into this house?????

I don't think I'd wanna spend much time in a vacuum sealed house with a wood burning stove going.

Good luck, hope you don't die