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How is my insulation system?
Last Post 02 Dec 2008 06:50 PM by Naudi2u. 20 Replies.
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aardvarcus
Basic Member
Posts:222
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| 11 Nov 2008 08:55 AM |
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I will be building a new custom home in Tennessee, 1300sf on a main floor and an equal sized finished basement. Almost all of my basement will be below grade, with the small walk out area insulated the same as the main story. Here is what I was thinking for my insulation system-
Attic=Drywall, Zip system OSB Taped,Prefab Trusses with 3' Blown fiberglass(only 2' at edges due to 4' overhang, 6/12 roof), and 1/2 R-Max boards, reflective side up.
Main Walls=Brick, Air Gap, 1/2 Dow Foam Board, Advantech, 2*4 24" OC wall w/ fiberglass batts, OSB, 2" R-Max Board, 2" R-Max Board with joints staggered and taped, 2*4 24" OC wall w/ fiberglass batts and all wiring, OSB, Drywall.
Basement Walls= 1/2 Dow Foam Board, 12" Blocks(Waterproofed inside and out), 2" R-Max, 2*4 24" OC wall w/ fiberglass batts and all wiring, OSB, Drywall.
Basement Floor= 4" Monoslab (Waterproofed on top.), 2" R-Max, 2" Rmax, Advantech (Floating),Underlayment, Laminate.
So what do you think? |
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PanelCrafters
Advanced Member
Posts:666
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| 11 Nov 2008 09:51 AM |
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Posted By aardvarcus on 11/11/2008 8:55 AM
I will be building a new custom home in Tennessee, 1300sf on a main floor and an equal sized finished basement.... So what do you think? Is there any reason that you are not considering SIPS, ICF's or spray foam?
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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aardvarcus
Basic Member
Posts:222
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| 11 Nov 2008 12:34 PM |
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I had considered each of them, and here is why I chose against them.
Spray foam does an excellent job of air sealing, but so will foil faced boards with taped joints. Because all my wiring and plumbing is on the inside of this air retarder, I will not have to worry about sealing around these fixtures. Spray foam does nothing for the heat loss across the studs of the cavity it is sprayed in. It is also very expensive, and I can DIY fiberglass and Foam Board to save some cash. If the price drops to a reasonable amount, I will probably frame my double stud wall and just spray it full, however I don't see the price dropping that much anytime soon.
Same thing with sips, but also I will be doing a lot of the work myself (plumbing, wiring, insulating, ect.) to cut costs. Since sips have this built in, I would essentially be paying someone else to do this, which is not in my budget.
Most of my blockwork will be below grade, and I am unsure of how the foam will stand up to years of rodents, moisture, and insects. My dow board on the outside of by blockwork is just to protect my waterproofing during backfill. Also, a normal block wall with R-Max on the inside is also cheaper for the same installed R-Value. Lastly, Nobody around here uses them. I would probably have to find someone from quite a distance away to be able to properly install them, which just adds time and cost.
Its not that I dislike this stuff, its mainly a matter of budget.
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PanelCrafters
Advanced Member
Posts:666
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| 11 Nov 2008 07:12 PM |
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Posted By aardvarcus on 11/11/2008 12:34 PM
Its not that I dislike this stuff, its mainly a matter of budget. Yea, if this is a mostly DIY project, I agree. Otherwise, it becomes a bit more complicated: Balancing the energy savings with the costs. I think your plan sounds good! For extra sealing, and if you like it messy, you might research using a bituminous sealant on the outside of the studs(or sheathing) prior to attaching your foam boards. Good Luck!
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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wes
Advanced Member
Posts:533
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| 11 Nov 2008 07:34 PM |
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Sounds OK for Alaska or Canada, but don't you think it might be overkill for Tennessee? |
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Wes Shelby
Design Systems Group
Murray KY
wandr@ainweb.net |
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slenzen
Basic Member
Posts:289
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| 11 Nov 2008 10:47 PM |
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Anyone have info on AirKrete insulation? |
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aardvarcus
Basic Member
Posts:222
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| 12 Nov 2008 11:10 AM |
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I realize that it seems excessive, but I don't really see it as overkill. I am planning on owning this home for the rest of my life. I consider the cost of the insulation to be an initial investment in an annuity. It will pay me dividends (in the form of lower utilities) for the rest of my life, with the payback increasing as the cost of utilities increases. Who wouldn't want to be able to invest some money and be guaranteed 20-30% interest a year, with that figure increasing as fuel increases?
I really don’t understand why more people don’t insulate their homes better.
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tesla-was-right
New Member
Posts:29
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| 12 Nov 2008 11:20 AM |
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www.airkrete.com
Airkrete is foamed magnesite (a totally mineral based foam)
It has higher "R" value than fiberglass but not as high as urethane based foam. (forget about supposed "Bio-based" foams. All that means is they have a portion of plant based content. They still are mostly urethane.
Airkrete will not burn and will eliminate the chance of mold in a cavity-wall assembly.
Look at their website and see the burn test video--quite impressive.
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Jelly
Advanced Member
Posts:552
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| 13 Nov 2008 12:07 PM |
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Airkrete sounds like a great foam, where it's applied correctly. But those pictures where they're filling the cores of concrete block - isn't that a total waste of time, money and material? The heat/cold will transfer right through the webs - filling the cores should have practically no insulative effect.
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aardvarcus
Basic Member
Posts:222
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| 13 Nov 2008 12:21 PM |
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Your right, but it isn't a complete waste. It is easier for the heat to flow through the air gap in the blocks than the web, so by filling the cores and eliminating the air gap, you are forcing the heat to travel through the web. I agree though that you would be much better off with a continuous layer applied over the foam. But, this may have also been part of a fireproofing system, not necessarily just an insulation system. They may have been creating a solid fire blocking wall, with the added insulation just as a bonus. |
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alynch
New Member
Posts:3
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| 13 Nov 2008 12:45 PM |
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Have you considered blown in cellulose instead of fiberglass?
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aardvarcus
Basic Member
Posts:222
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| 13 Nov 2008 02:31 PM |
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I did consider it, but I am worried about the long term fire resistance of cellulose after many heat/cool cycles cause the humidity to dew and wash the chemicals out. Also, the weight of 3' of cellulose would compact the insulation that is on the very bottom.
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alynch
New Member
Posts:3
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| 13 Nov 2008 04:04 PM |
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I would suggest that you visit www.cellulose.org This is very factual and unbiased information in regards to fire safety and longevity. Attic--15 inches (not 36) of cellulose will give you an R-50. Probably over-kill in your climate. 12.25 inches will give you an R-38. When boric acid is added to cellulose it WILL NOT burn. Humidity and dew will not wash the chemicals out. You can hold a blow torch on it for 10 minutes and it won't burn. You could not do that with fiberglass. The same boric acid that prevents it from burning also prohibits mold, mildew, bugs, ants, pests, etc. The sound density with cellulose is unparalled as well. The acoustics of your home will be amazing. You can't "fluff" cellulose. It is so dense (which is what makes it so effective and also keeps it from burning as fire needs air to breathe) does a much better job of filling in around plumbing and wiring.
You're on a "Green" website. Cellulose is made from no less than 80% post consumer recyled newprint and uses 1/8th of the embodied energy as fiberglass. It is the greenest of the green. |
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aardvarcus
Basic Member
Posts:222
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| 13 Nov 2008 06:59 PM |
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I'm not saying that nobody should use it, you should just look at the facts and make an educated decision. You have made some valid points, points that I considered when I made my choice.
I would suggest that you visit www.cellulose.org This is very factual and
unbiased information in regards to fire safety and longevity.
The site is run by the "Cellulose Insulation Manufacturers Association." I usually look to someone completely unaffiliated for my testing data.
You're on a "Green" website.
Cellulose is made from no less than 80% post consumer recyled newprint
and uses 1/8th of the embodied energy as fiberglass.
True, it takes less energy to manufacture cellulose, mainly because they are ignoring everything before when the recycled newspaper shows up at their facility. I know several people who save their newspapers until they get a box full, and then drive them to the recycling center, a 15 mile trip, burning a gallon of gas round trip. All for enough paper to make about 15 lbs of cellulose. How is that saving any energy?
It is the greenest
of the green. I'm not even going to get started on "greenwashing".
Attic--15
inches (not 36) of cellulose will give you an R-50. Probably over-kill
in your climate. 12.25 inches will give you an R-38.
After you just told me the importance of using less energy and the importance of being green you now want me to put in less than half of the R-value I was going to install? Don't you thing the energy savings of my R-120 over the lifetime of my house will make up for the little extra energy used in manufacture? A truly "green" house will try to minimize impact over its entire life, not just in construction. Can you really have overkill when it comes to helping the earth?
When boric acid is
added to cellulose it WILL NOT burn. Humidity and dew will not wash the
chemicals out. You can hold a blow torch on it for 10 minutes and it
won't burn. You could not do that with fiberglass. "http://www.cellulose.org/BuildersContractors/DispellingMyths.php"
Insulation Type |
Flame Spread |
Smoke Developed |
|---|
| Cellulose insulation |
15-20 |
0-5 |
| Fiberglass |
0-5 |
<50 |
Then why does your web site say a fire will spread 3-4 times faster on(new)cellulose than it does on fiberglass? I admit it won't smoke as much, but smoke rises, so it will leave my gable vents. Don't take my word on the humidity washing it out though. Find some cellulose that has been installed for 10-15 years, take a handful outside and try to light it. You might be surprised.
The same boric acid
that prevents it from burning also prohibits mold, mildew, bugs, ants,
pests, etc.
As long as the acid is still there, you are correct.
The sound density with cellulose is unparalled as well. The
acoustics of your home will be amazing.
I believe you mean sound transmission, and you are correct. However, the real key to any sound isolation system is lack of bridging, not the sound insulating material. Fiberglass has similar dampening properties.
You can't "fluff" cellulose.
It
is so dense (which is what makes it so effective and also keeps it from
burning as fire needs air to breathe) does a much better job of filling
in around plumbing and wiring.
Cellulose does settle, about 10-20% from when it is installed. Look it up on any cellulose installers website. That is why it is important to fluff it just a little when it is installed. For example, if you buy 12" of blown cellulose, it should be installed to a depth of 13-14". Thus when it is settled, it will have very close to the rated R-value. If you install it at 12", it will settle and have less than the rated R-value. The settling is not a problem, it is just something that needs to be accounted for. Just FYI for those of you who are going to use it.
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greentree
Basic Member
Posts:183
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| 15 Nov 2008 12:00 AM |
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Cellulose packaging gives you settled thickness coverage on the package, actually quite clearly. |
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alynch
New Member
Posts:3
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| 15 Nov 2008 08:22 PM |
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I've never heard of anybody in the "midwest" going with an R-120? |
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Naudi2u
New Member
Posts:49
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| 29 Nov 2008 11:45 AM |
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Man R120 is alot. Northern Wisconsin R30 is the norm. I think that your cost to return is is not going to help. We just built a home for a customer that sprayed a inch of poly in the walls for a extra cost of 2000, But went cheep on the windows. Spending the extra 2k on the windows would have been better spent.
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Carlo
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greentree
Basic Member
Posts:183
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| 30 Nov 2008 07:57 PM |
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Carlo, R38 is the minimum in northern Wisconsin. |
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Naudi2u
New Member
Posts:49
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| 01 Dec 2008 07:16 AM |
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right r38, that was a typo
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Carlo
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aardvarcus
Basic Member
Posts:222
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| 02 Dec 2008 08:59 AM |
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Posted By Naudi2u on 11/29/2008 11:45 AM
Man R120 is alot. Northern Wisconsin R30 is the norm. I think that your cost to return is is not going to help. We just built a home for a customer that sprayed a inch of poly in the walls for a extra cost of 2000, But went cheep on the windows. Spending the extra 2k on the windows would have been better spent.
I don't plan on going cheap anywhere. I also plan to live in this house for a long time, so I will have a long time for the insulation to pay me back. After I started looking at the cost of high quality well insulated windows, the cost of getting R-120 blown in my attic doesn't seem all that outrageous to me. The R-120 in my attic will also make my wall insulation and windows work harder for me. 120 might be a bit excessive, 80 would probably be enough, but once you have the professional on the job, getting him to blow a bit more is cheaper than having him come back later if I were to change my mind.
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