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newbiejohn
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Posts:141
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| 03/30/2009 5:22 PM |
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If in a traditional basement I was to use the Dow Blue Board Insulation on the exterior of the wall, im assuming you cannot go all the way to the top ? Meaning, there is generally a few feet of insulation above grade showing, is there anyway to go all the way to the top to insulate the entire basement and cover that part above grade with something else ?
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thagreen
Registered Users
Basic Member
Posts:120
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| 03/31/2009 7:09 AM |
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I believe the use of parging or stucco is common practice for this application. Proper install is according to manufacturer. In place of dow why not go w/2'' 2x8 sheets eps, keeps its insulating factor much longer and less costly. Found a study on this if your interested but i'm sure I've put it up for discuss on the forum.
Cheers! |
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newbiejohn
Registered Users
Basic Member
Posts:141
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| 03/31/2009 7:40 AM |
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| Yes can you post the list for me...curious to read it... |
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thagreen
Registered Users
Basic Member
Posts:120
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| 03/31/2009 8:08 AM |
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here it is. www.foam-control.com/downloads/brochure/Foam-Control-EPS-Water-Absorporation-Facts.pdf
Cheers! |
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Dan Morrison
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New Member
Posts:20
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| 04/14/2009 10:17 AM |
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Yes, you can go all the way up, just like an ICF would, right? You can parge with synthetic or real hard coat stucco. Or you could use a cement board to protect the outside.
But that seems like a lot of extra work when you can make it easier by stopping the blue board just below grade and insulating the top of the wall on the inside with spray foam making sure to hit the rim on the inside as well.
Regarding the type of foam to use, here's an excerpt of an article on rigid foam that we haven't published yet on www.GreenBuildingAdvisor.com yet (coming soon):
Expanded polystyrene
The least expensive of the three, EPS has an R-value of about 4 per in. It can be manufactured in different densities to in-crease its compressive strength but it’s still not as strong as extruded board and it’s more susceptible to crumbling at the edges and to other job-site damage. EPS is relatively open to the passage of water vapor with a permeance of 2 to 5, depending on the density of the board. This makes ita semi-permeable material. EPS can absorb more water than either of the other two types, from 2% to 4% by volume, making it a second choice for below-grade installations. EPS is often used on walls and roofs and commonly as the core material in structural insulated panels and in insulated concrete forms.
Extruded polystyrene
Stronger and more expensive, extruded polystyrene (XPS) also is a better thermal insulator, rated at R-5 per in. It’s more water-resistant than EPS and has much lower permeance to water vapor(1.1 per in.). When the thickness is increased to 2 in., the permeance drops to 0.55, making this a semi-impermeable material. Because of its higher strength and water resistance, XPS is often used below grade to insulate slabs and foundation walls.
Polyisocyanurate
With higher insulating values (up to R-6.5 per in.) and the elimination of ozone-depleting blowing agents, polyiso board has some advan-tages over XPS for above-grade use (it’s not recommended for below-grade applications because it can absorb water). Polyiso often comes with
a foil facing, which gives the material a very low vapor permeance of 0.03.
Good luck,
Dan |
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Dan Morrison
Managing editor
GreenBuildingAdvisor.com |
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Polycore
Registered Users
New Member
Posts:64
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| 04/16/2009 4:55 PM |
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Dan that was a great post about different types of foam, very informative. The only thing to add is that Extruded polystyrene is subject to ozone-depleting blowing agents being released over time, "Off Gassing."
Expanded Polystyrene is the most cost effective and readily available of the three types of rigid insulation, in my opinion. |
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Polycore Canada Inc.
www.polycorecanada.com
1-877-765-9267 |
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aardvarcus
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Basic Member
Posts:176
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| 04/17/2009 11:24 AM |
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It depends on your application really. Because of the lesser R/inch, it takes more inches of Expanded to equal the same R value of Extruded. For example, a wall sheathed with expanded will be thicker than a wall with extruded for the same R value, and will either eat up interior space or my lead to the foundation having to be enlarged. In this way, a more expensive foam can actually be cheaper overall.
However, for slapping against a below grade wall, anything goes. If you want to save some money, try to find a good source of missized or cull pieces, my dad found expanded poly sheets 2 3/8" thick 3'-3" *7' for $3 each.
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