cellulose vs. fiberglass
- Thread starter stigedis
- Start date
Radix2
Well-known member
There are recent studies that show fiberglass is less effective in cold climates due to how easily air passes through it. So a given level of inches/r-value for cellulose will be more effective. I was convinced enough that I took back a truck full of fiberglass for blowing in an attic and bought the cellulose instead.
I didn't find much difference in cost - what are you seeing ?
I went with a closed cell foam flash followed by dense packed wet cellulose in walls, and regular blown in cellulose in ceilings. Cellulose also blocks noise very effectively.
I didn't find much difference in cost - what are you seeing ?
I went with a closed cell foam flash followed by dense packed wet cellulose in walls, and regular blown in cellulose in ceilings. Cellulose also blocks noise very effectively.
lazer50
Well-known member
I went with an older friend to get insulation for an older house.i did some research but didnt understand it all.so at the store a build specialist explained that cold air passes thru fiberglass much easier than cellulose and i believe it took less material.cost was similar so we went with cellulose and blew it in.
kwschumm
Well-known member
We had cellulose installed at our house. It is supposed to be fire treated with boric acid which, supposedly, will kill ants but it didn't kill OUR ants. They treated it like an ant farm (we could see them through the fabric in the unfinished basement). We also found cellulose to settle some in those walls even though they said it wouldn't. Still, we would go with cellulose again. The energy calcs showed it to give better performance than fiberglass and no worries about airborne glass fibers (http://inspectapedia.com/Fiberglass/Fiberglass_in_Air.php).
gregtwojeeps
Well-known member
Blew in cellulose in attics and existing walls as a business of my brother and I for years in the 70's and liked it then.....
Blew my homes attic in 2009 that we just moved from. Still like it. The only problem I had in 2009 was I had to use Lowes blower. What a mess. NO air control adjustment and the attic was full of dust and it "fluffed " the insulation needlessly and even with a 3M respirator mask I about puked from the dust.
I had a Hagen Pro blower in 1974 that I could tune the air down to where the insulation came out of the hose like a rope, and I barely needed a mask, and still would not clog up the hose. JMO
Blew my homes attic in 2009 that we just moved from. Still like it. The only problem I had in 2009 was I had to use Lowes blower. What a mess. NO air control adjustment and the attic was full of dust and it "fluffed " the insulation needlessly and even with a 3M respirator mask I about puked from the dust.
I had a Hagen Pro blower in 1974 that I could tune the air down to where the insulation came out of the hose like a rope, and I barely needed a mask, and still would not clog up the hose. JMO
toyotadriver
Well-known member
- Joined
- Dec 30, 2010
- Messages
- 1,586
I just built a house and we insulated it with damp spray cellulose in the walls and dry blow in for the attic. I like it and would use it again.
75gmck25
Well-known member
Have you also looked at mineral wool? I bought some Roxul Safe&Sound to use for sound control and it seems fairly easy to work with. Its also fireproof, which would seem to be a good feature in a garage.
Bruce
Bruce
zmaxmotorsports
Well-known member
I've always used fiberglass in walls just because its,easy,but I definately prefer blown in cellulose in attics.
Especially if I have to spend any time working up there.
Especially if I have to spend any time working up there.
theoldwizard1
Well-known member
How long do you have before you have before you must cover (drywall) the sprayed on cellulose ? Any issues putting up the drywall ?
theoldwizard1
Well-known member
theoldwizard1
Well-known member
Which is why you need a house wrap !
YEP ! Kraft faced 'glass is an easy DIY.
jbwilkins
Well-known member
Depends on the temperature, current relative humidity, and how wet it was when you sprayed it in...if you wait a few days to a week you should be ok.....However there were issues in Dallas with a national builder why sheet rocked over wet blown cellulose to quickly and it caused mold, primarily in the 2x6 walls though....
One thing about cellulose in walls that the batt guys typically bring up is settling.....Cellulose does settle, just blow your attic to 10" or so and come back in a few months and measure it, you'll probably be at 9" or less in depth.......In a wall you're looking at 8' of depth settling once it's dried and the adhesive has given way....I've never been involved in deconstructive testing on the stuff so I don't know if this is true or not, but something to think about.....I'm talking new construction here, retrofit tends to 'pack' the cavity so settling shouldn't be as big an issue....
It does a better job air sealing than batt insulation (product is denser, and fills voids) and it goes in easier (no need to split batts to go around wires, fills in behind electric outlets, etc.) and it makes the structure seem quieter.....It's also typically treated with borate as a flame retardant, which also kills/repels bugs (think roach proof).....
I'm not an expert, but there is one consideration that's been overlooked....weight. If you have a situation where you want/need to limit the amount of weight you're adding, cellulose is heavier than fiberglass for the equivalent R value.
When I built my shop I talked to the truss company and building inspector about it because I was planning on adding a steel liner panel ceiling, 4' wide roll insulation between the trusses (it was free) and then blowing cellulose over the top and wanted to make sure I wasn't going to wind up with an issue (mostly from the inspector).
When I built my shop I talked to the truss company and building inspector about it because I was planning on adding a steel liner panel ceiling, 4' wide roll insulation between the trusses (it was free) and then blowing cellulose over the top and wanted to make sure I wasn't going to wind up with an issue (mostly from the inspector).
Yes, but holes in top plates for wires, holes for outlets and switches need to sealed also.
toyotadriver
Well-known member
- Joined
- Dec 30, 2010
- Messages
- 1,586
Depends on lot of factors. I waited about a week. No issues.
No problems with the drywall.
Need to do that regardless, whether fiberglass or cellulose.
Maybe but it doesn't get done that often
Radix2
Well-known member
I have an area that has been up uncovered for about a month so far, the binder used to hold the stuff together stops it from falling out or settling. I don't see why it wouldn't stay up for years unless knocked out. If you want to get the moisture way down, it takes a week for the dampness to go away.
The insulator told me that most of the time the builders are right on his tail so the drywall goes up with only a day or so to dry. I said not on my house...we waited about 5-6 days.
engineer2
Well-known member
I would only do cellulose if you could absolutely seal the exterior walls against rodents. Turns out mice love the stuff. I have found tunnels in many of our walls where mice got in. They actually chew through the exterior sheathing to get in.
Sealing the holes in top plates and other inter-floor penetrations is required by building code here whether you insulate or not for fire blocking. Doesn't seem to make sense when the whole wall framing is open anyway. But the inspectors are very particular about it
Last edited:
theoldwizard1
Well-known member
I would wait also. At least a week, maybe 2.
I do know that dry, blown in cellulose will settle, but I wonder about the wet stuff.