I am insulating my attic floor and can only fill in 6" the floor joist space. I am in a coastal southern climate so I am worried about keeping my A/C in and heat and humidity out. Also, can I put a vapor barrier (sheet plastic) over the whole floor as an added protection?
2007-04-17 02:39:51 · 6 answers · asked by smithy1023 1 in Home & Garden ➔ Maintenance & Repairs
Fiberglass will breathe better in your enviornment. Cellulose is too tight, & gets blown in wet. In an area with high humidity, it will take a long time for the cellulose to dry.
Fiberglass is the way to go, & no plastic vapor barrier, but you can put plywood over it, then you also create a small storage space.
Hope this was helpful, good luck!!
2007-04-17 02:48:18 · answer #1 · answered by Anonymous · 2⤊ 0⤋
Use the fiberglass bats and install the vapor barrier (paper) down towards the lower floor ceiling. If you install a vapor barrier (plastic) on top of the joists, it will cause moisture problems with the lower floor rooms. Vapor barriers always go towards the heated/cooled space. You could use fiberglass without vapor barrier. Blown in insulation will settle after a time and leave a gap between the attic floor and insulation.
2007-04-17 11:35:13 · answer #2 · answered by sensible_man 7 · 0⤊ 0⤋
The vapor barrier needs to be as close to the heated/cooled space as possible, between the space and the insulation. I like to use a coat of vapor barrier paint inside, just for added measure. Any good alkyd enamel will work for that.
Cellulose has a higher R-value per inch than fiberglass, and is not blown in wet in a situation like yours, so that is not an issue. Cellulose can "compost" if it gets wet and stays wet for long enough, so in your humidity...I'd go with 6" fiberglas batts, with a vapor barrier on the bottom. If you can't use batts, blow it in. (like if the floor is already laid and you don't want to pull it up.)
Be sure to ventilate the attic correctly, and take your time to seal all the holes from wires/pipes/flues and other penetrations into the heated/cooled space. Foam big holes, caulk smaller ones. Be sure the insulation has no gaps in it. If you have gaps....humid outside/attic air will condense against the A/C cooled ceiling.
2007-04-17 11:04:23 · answer #3 · answered by roadlessgraveled 4 · 0⤊ 0⤋
When I did my floor, I used a fiberglass batt with a vapor barrier already attached and just used a nailer to install inside the joists. Worked good.
2007-04-17 11:26:31 · answer #4 · answered by Fordman 7 · 0⤊ 0⤋
My definition of a properly ventilated attic is a powered ventilator with a thermostat and an on and off switch. It can be installed easily on a seal tab roof or in a gable opening. Wind turbines are not the same as I have described. I remember building a shop in NOLA for a company I worked for and we put bat insulation between the rafters as well as between the ceiling joists.
2007-04-17 23:26:18 · answer #5 · answered by Grendel's Father 6 · 0⤊ 0⤋
what would be best to use in my Michigan home? fiberglass or blow in cellulose? and should I us blown in fiberglass of roll. redoing Attic .
2014-09-22 15:04:15 · answer #6 · answered by Veronica Marion 1 · 0⤊ 0⤋