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I think you should look into blown in cellulose if cost is a concern, and sprayed in foam is going to be especially expensive.
Search for "Mooney Wall", or find Mike Smith's "Adverse Conditions" thread in the photo gallery section. Scroll through the pages until you find the insulation section. He uses a stud wall and horizontal strapping to avoid thermal bridging, and blows cellulose behind a mesh fabric before drywall goes up. Cheap and effective.
Blown in cellulose and rigid foam would be another option. FG usually has more voids and cold spots than cellulose.
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
Does blown cellulosu in walls settle adn leave voids at teh top of the wall?
NO, not if the cellulose is packed tightly when it is installed. 3 lbs per cubic foot is what we use. The natural settled density is just under 2 1/2 lbs per cubic foot. To reach density higher than that mechanical asstiance in needed.Garett
How do you determine the 3lbs (as in how do you know when you're at 3lbs)?
jt8
"One of the fondest expressions around is that we can't be the world's policeman. But guess who gets called when suddenly someone needs a cop." -- Colin Powell
grott.... all our cellulose charts say settled density is 1.4 lb/cf
and the blow-in wall tables assume 2.7 lb/cf
once we get to 3 lb/cf, we assume dense pak
my guess is the theoretical max is 8 lb/ cf which is what our bales are before we open them..
anyways.. it would seem that anything above 1.4 cannot settle...
EDITED TO ADD:
in looking over my notes from Steve Zerby ... who quotes FredL quite a bit... they seem to agree with you that no settlement occurs after 2.5 lb/cf
and air-sealing occurs at 3 lb/cf... >>>>>
do you have different data than that ?
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 2/15/2007 3:46 pm ET by MikeSmith
That depends on whether the instaler has any idea what he's doing
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Greetings j,
That subject has been addressed here on Breaktime a number of different times in the past.
While waiting or in the event you fail to receive the information you desire, you might find it in the archives.
If you scroll to the upper corner of your screen there is an advanced search function that will take you to previous threads dealing with whatever you type in the search bar.
If you type in 'fiberglass batt', 'fiberglass insulation', 'foam insulation' or other keywords of the subject matter you'll get a supply of data from those old threads.
It's has been said that unlike foam insulations, fiberglass R values will actually decrease proportionally to the colder the temperatures get.
Cheers
only life affirming platitudes allowed -Doud '07
Would a full cluster of enemies be called an enema? -Piffin
Rez:
Although I'm very familiar with the discussions of FG (good) vs. cellulose (better) vs. foam (best) and the drop in R value of FG with lower temperatures, I've often wondered how effective properly installed FG batts in sealed wall cavities would be when 3/4" blue board is applied over outside the OSB board). The local Habitat for Humanity group here (<!----><!---->NE Ohio<!---->) uses this approach believing that the foam board minimizes the declines of the FG R-value. Have there been discussions on this approach? (P.S. we built a house last year and paid extra for the blown in (damp) cellulose into the wall cavities).<!----><!----><!---->
Rookie<!----><!---->
<!----><!---->
So another poor soul buried in NE Ohio snow.
My personal observation as one less than a rookie would lean towards seeing the foamboard insulation on the exterior side of fiberglass batts in a heating climate being beneficial towards keeping the fiberglass batt R-value from lessening,
in that keeping the harshness of the coldest temps buffered to connect to the fiberglass by the foamboard.
However, I say that only as an uninformed observer without the use of technical testing data.
It would seem that somewhere in the abyss of the BT archives discussion dealing with the like most probably exists but finding those specific threads can prove daunting without the help of the other board members.
Hang on, maybe we'll get lucky.
be a squinting eye and .44 magnum saying 'are ya feeling lucky?'
only life affirming platitudes allowed -Doud '07Would a full cluster of enemies be called an enema? -Piffin
So another poor soul buried in NE Ohio snow.
we got 11.3" in 24 hrs. Doesn't sound impressive to me, but the news folks are calling it a 'blizzard'. Blizzard my a.., that was just a bit of snow.jt8
"One of the fondest expressions around is that we can't be the world's policeman. But guess who gets called when suddenly someone needs a cop." -- Colin Powell
Isn't laying foamboard over studs, whether inside or outside, a royal pain? More material, more labor, and certainly a pain to reframe around all teh windows and doors in order to allow for trim.
Some are content with canned beer,
some with bottled.
Some have to make their own.
Some a balance of flavor and how problematic to produce and
some pull out all the stops to reach a desired end.
be a Mooney wall.
is today Saturday?
In Alaska, the foam must be on the inside of the wall. 50/50 which side is best in OhioTests showing Fg batts to be porr were done in sealed wall cavities
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
thanks to all who responded seems i need to do some more searching the archives..has anyone heard of the moisture problems with sprayed in eurathane (even with hrv)....thanks
No such thing with sprayed in urethene. It ios closedcel and eliminates the dewpoint
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Do a fair amount of searching the web on info on managing movement of both heat and water vapor. Most often cited reference is http://www.buildingscience.com. As to foam, note the difference between open and closed cell foams. The open cell, nominally 0.5 lb/cuft., is a lot less money, but has R value in the range 3.6-3.8/inch and has higher permeability than what usually passes as vapor retarder. The number I have seen is 6-10 perms for 3" thick. Permeability goes inversely with thickness, so 6" would be 3-5 (vs. 1 for a "VR"). Closed-cell foam is nominally 2 lb/cuft, has an aged R value of 6.0 or so per inch. It also is a lot less permeable as far as water vapor goes, so it doesn't need a VR (although the BI may want to see one). Both, if applied properly, will seal against the sheathing and joints with framing, to keep out air infiltration and to avoid convective transport of inside air through the wall to cold spots. Use a HRV for fresh air and humidity control. In your climate, I wouldn't use FG in the walls or ceiling, because of the now well-known loss of R value as temperature difference across the wall gets more than 25 F (and gets progressively worse as the difference increases and thus the difference in air densities on cold and warm sides gets greater. Do a search for the report from the Oak Ridge Lab Large Scale Climate Facility, done around 1990; that covers FG vs. cellulose in an attic floor. It's all out there to see on the web and mull over.
Here is the Mooney thread
http://forums.taunton.com/tp-breaktime/messages?msg=65624.1
Mike Smith has the most experience with the Mooney. I'm giving it a try on my current project. Prior to decided on the Mooney, I had been thinking of FG batts in the 2x4 bays and then 1" EPS then either horizontal blocking/drywall, or just drywall without the blocking.
But I really don't like fg batts and am always willing to try something else.
jt8
"One of the fondest expressions around is that we can't be the world's policeman. But guess who gets called when suddenly someone needs a cop." -- Colin Powell