cellulose in walls for insulation ?????
| Putting up a new workshop …. 3500 sq ft …. 16 ft walls … 1000 sq ft attic for storage (so 4500 total). So, I have been reading posts for two days and am completely confused. I was looking at blown fiberglass in the ceiling but I read that fiberglass losses its R value as the temp drops … and we do get cold here in Vermont .. like -30 cold. With batts it is hard to insulate between the trusses. So it looks like blown in Cellulose … about 20″ The walls are confusing me … Fiberglass batts are easy to put in and relatively cheap. I read about dry packing blown cellulose but am not sure. Seems after a few years it settles and you can get a gap at the top of the wall. I read about wet packing …. I know they say you can’t do it yourself but I would be willing to try (a water spray nozzle on the end of my blower hose). Again, I read two posts talking about settling even with it being wet. Plus I am not sure about mold .. they talk about 6 months to dry out. I did read one post where someone mentioned “glue” … could you add something like white glue to the water when spray …. maybe just say 2 to 5 % ???? Plus I keep thinking,if they are getting settling on an 8 ft wall … how much will I get on 16 ft ? This is a shop and I am on a budget so things like spray foam are out of the question. I am a DIY guy … just finished building a 4800 sq ft house … so I will be doing this myself. Any thoughts or ideas ????? Thanks …. Mike | |
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Replies
Suggest mineral wool batts for the walls. Easier than fiberglass to install correctly. has higher R-value, and much smaller convective losses at low temperatures. Does not sag.
https://www.greenbuildingadvisor.com/article/mineral-wool-insulation-isnt-like-fiberglass
You can blow cellulose into walls. Put up some sort of sheathing, drill holes in it (generally two per stud space) and blow it in.
It does take some skill/training to do it right and fill the cavity.
The cost on spray foam has come way down. You may wish to investigate. Closed cell foam makes a huge difference.
Good luck.
I really would love to go with spray foam. We used it on the house I just built on the rim and on two ends of a vaulted ceiling.
Still it is about 4 times the price ... cheaper than it was (was up about 10 times a few years back) but still out of the budget for a workshop.
I am just trying to get my best "bang for the buck".
Mike
I love wet pack cellulose for walls but I don't think it's reasonable to do it without the proper tools. I haven't priced it lately but it always seemed good value compared to fiberglas. In your case some of the value judgement needs to consider the cost of your conditioning. If you do it all on paper it will usually reveal a clear choice.
. Some places around here will loan you a blower if you buy cellulose to blow in the attic. My choice there even if you spray foamed first.
I hate just about everything about fiberglas but the cost. Not so sure about the value. I just insulated a small wall with 3.5" owens corning ecotouch which claims r-15. I'm not sure what all is in it but it claims to be 55% recycled material. It certainly was easy to work with for batts and it did seem to be a better install/fit than normal fiberglas batts. It was also inexpensive but I think that was just the supplier smiling on me, looking at home despot prices online it looks pretty pricey.
Thanks ...
Here if you buy 10 batts, they lend you the blower ... but it is a dry unit.
I can rent one ... same problem ... dry unit.
This is the only reason I am thinking of just putting a small adjustable water jet on the end of the hose ... from looking at pictures, it looks like this is what the factory does.
I try asking around ...on one in this area (northern Vermont) has used the wet process ... I even called three insulation companies ... they all offer foam .... batts in the walls and ceilings .... and blown dry cellulose for attics.
I have used fiberglass all my life (and had dry cellulose blown in the attic for me) ... might be the way to go ... just keep reading how cellulose in the walls is much better.
Mike
Mike,
I had wet cellulose installed in my 2x6 residential walls fifteen years ago and I love it. The home is quiet and heats well.
The dry cellulose had a glue powder mixed in and that was blown through a fine water mist at the end of the blower hose. When I handled the activated (wet) insulation it felt like it had Aquanet hairspray on it. Tacky but not actually wet. Mine was installed in the winter and dried quickly. I gave it a week or two then hung the drywall.
Mold is everywhere. Control moisture in the building and you'll be fine. If a building has enough moisture to support mold growth in cellulose it will also support mold growth on wooden members and other organic things.
Jack
You answered the question I have been searching for all day!
I figured there had to be some kind of glue in it.
Thanks !!!!!!!!!!!!!
Mike
Our 1996 home in Virginia had cellulose insulation blown into ceiling of our sunroom. I'm guessing they filled to the top of the 8" rafters. The cellulose had compacted down to about 4". I chose to top off with blown in fiberglass. Amazing difference in comfort. I have added access to all ceiling and added blown fiberglass. Not happy with the sunroom cellulose. Is that compaction normal?
Hmmmm ... I would like to know this also!
I looked at blown fiberglass ... it is actually a bit cheaper than cellulose.
Two problems ... and maybe someone can help here ....
1) The R value of fiberglass seems to go down as the tempurature differential goes up ... that is it may be an R40 at 75 deg in and out of the building but might only be an R20 when the weather outside is 20 and inside 70. Is this true ????
2) I read something about blown fiberglass not working as well also because of the open top in an attic. It said cellulose "fills" or packs tight and the insulation value is based on the the material. In fiberglass, the insulation value is based on it hold air pockets ... which is a problem if one side of the insulation is exposed. Is this correct ????
I tried a few "energy" sites ... even our own Vermont energy could not give me a straight forward answer.
Thanks ... Mike
1) True. Fiberglass is a fairly open structure, so convective air flow within the insulation reduces the effective R-value. The bigger the temperature difference across the insulation , the larger the loss.
2) Almost Correct. The cellulose has small air pockets with the product itself, and when blown in, traps air between the cellulose particles as well. The cellulose will settle and close off the convective air movement better than the fiberglass does. Fiberglass does not have any significant R-Value in the glass fibers, relying on the air pockets to provide the insulation. Convective air movement will move the warm air upward, and if the top of the insulation is open, escape.
Normal cellulose compaction is 15 to 20%. The original application was closer to 5" deep.