Insulation batts are flatt!

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

Hass

Minister of Fire
Mar 20, 2011
528
Alabama, NY
Early this year I bought more insulation than I needed (about 13-14 extra rolls)
It's all R-13, 32' length.

Now that I'm using them, they're all flat as a pancake.
Well maybe not that flat, but they're not 3 1/2.
They rolls are about 2", some spots are 2 1/2" thick.
If I throw it in the wall, will it eventually expand to regular thickness?
Or should I fluff it up before I put it in?
Fluffing it will be a mess, time waster, and frankly it's a pain in the rump.
I'm assuming it's just because of how tightly they are rolled, and over time it will fluff to it's normal thickness.
It hasn't been damp or anything like that.

I think I may go ahead and add 1/2" or 1" of foam board in there before I throw the batts in... since it's 3 3/4 to 4" thick walls (not 3 1/2")


humm... $120 to do all the walls with 3/8 board.


EDIT:
Nevermind.
Aside from the fact that the walls are 18" OC and it's a pain to insulate, I'm just going to blow it in.
Put up the first 48" Panel all around the house, blow it in so it's easy to avoid the blocking @ 40".
Then put up the rest and pop a hole and do it that way.
Don't have to worry about not getting it all the way through, or stapling it up, or making sure I properly insulate around the blocking, etc....
 
You still need a vapor barrier on the inside. Maybe if you tack up plastic sheeting well enough, you can just blow it in through that and then put up the wall board. Most rockers put the top sheet up first and work down...
 
CTwoodburner said:
You still need a vapor barrier on the inside. Maybe if you tack up plastic sheeting well enough, you can just blow it in through that and then put up the wall board. Most rockers put the top sheet up first and work down...

Code says no vapor barrier on the inside of a dwelling, if the exterior has foam or a vapor barrier (tyvek)
Moisture gets trapped and rots your studs and the cold air meets the warm air and forms condensation between your walls.
Although how that moisture gets in between your walls in the first place I'm not sure... :|
 
Hass said:
CTwoodburner said:
You still need a vapor barrier on the inside. Maybe if you tack up plastic sheeting well enough, you can just blow it in through that and then put up the wall board. Most rockers put the top sheet up first and work down...

Code says no vapor barrier on the inside of a dwelling, if the exterior has foam or a vapor barrier (tyvek)
Moisture gets trapped and rots your studs and the cold air meets the warm air and forms condensation between your walls.
Although how that moisture gets in between your walls in the first place I'm not sure... :|

Then why does everyone insist on tyvek when getting their siding done?
 
When did Tyvek become a vapor barrier ?


It is supposed to stop drafts and water, like a raincoat that breathes.

Warm heated moisture laden rooms need the vapor barrier to protect the insulation.

Down South with air conditioning I guess they use nothing. Or it is on the outside.
 
billb3 said:
When did Tyvek become a vapor barrier ?


It is supposed to stop drafts and water, like a raincoat that breathes.

Warm heated moisture laden rooms need the vapor barrier to protect the insulation.

Down South with air conditioning I guess they use nothing. Or it is on the outside.

Quite right. Tyvek actually breathes. After thinking about this i called my buddy to discuss. Tyvek has tiny 'pores' and does breath but repels wind and water.

PS - and your vapor barrier needs to be on the inside/warm side of the house.
 
billb3 said:
When did Tyvek become a vapor barrier ?


It is supposed to stop drafts and water, like a raincoat that breathes.

Warm heated moisture laden rooms need the vapor barrier to protect the insulation.

Down South with air conditioning I guess they use nothing. Or it is on the outside.

Sorry, Vapor retarder.

Poly on the inside + tyvek on the outside = mold + rot in the middle, from when cold air meets the warm conditioned air, drawing the moisture from the air, dripping down your walls.
Kraft on the inside + tyvek on the outside = okay in most cases.

Tyvek + Foam is my route.
My house is sitting on a single row of cinder blocks, with a tiny bit of stone underneath them.
It's pretty damp... so I'm not taking chances with rot. About 8" of the house is below grade.

My insurance agent wouldn't believe me when I said the house has no steps. She kept telling me, she needs pictures of entrance ways and every stair MUST have a railing. I'm like, there are no stairs... WHAT DO YOU MEAN THERE ARE NO STAIRS? There are no stairs ma'am... Ok well any set of stairs needs a railing. don't take pictures of stairs without a railing. /sigh.

CTwoodburner said:
Then why does everyone insist on tyvek when getting their siding done?

Some people prefer #30 asphalt felt.
Kraft and tyvek is fine.
Poly and tyvek is not... unless you live way up north.
 
Status
Not open for further replies.