Using EPS for sub-slab insulation
My understanding is that XPS has better ‘water repellent’ properties than EPS so is superior for sub basement slab insulation. I would prefer to spec EPS for its lower Global Warming Potential and I know there are several densities for EPS.
我需要为低年级应用规定某种类型的EPS吗？
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This used to be the prevailing wisdom, and I still tend to subscribe to it. But some studies have shown little water absorption and no freeze-thaw deterioration from subgrade EPS after many years. I would certainly use a higher-density board if it's available, which would have both a higher compressive strength and less air and water permeability.
If you're considering using it sub-slab - or any other structural application - then it should be at least 25 psi foam.
J,
Plenty of people are successfully using EPS under slabs. One popular type for this application is Type 9 EPS with a density of 2 pounds per cubic foot and an R-value of 5 per inch.
To my knowledge, the Greenhouse Gas impacts of Expanded Polystyrene (EPS) is far more serious than the impacts of Extruded Polystyrene (XPS). Durability shouldn't be a problem if the material is completely buried and good site drainage is provided. These are necesseties with both types of foam. Water intrusion is usually a much more serious issue as it pertains to wall assemblies. Generally, I would reccomend XPS for this application.
According toAlex Wade, including both the plastic and the blowing agents, XPS has 50 times the lifetime Global Warming Potential of EPS.
Thanks for the quick feedback.
Tony according to an article Alex Wilson wrote for the June 1, 2010 publication of Environmental Building News titled "Avoiding the Global Warming Impacts of Insulation" XPS and ccSPF stand out as having a greater impact compared to others insulation options because of the blowing agent (HFCs) currently in use.
This won't help me for this project but I am also wondering if rigid board mineral wool insulation is a good option of sub slab (not sub footing) insulation.
Robert beat me to the draw. I'm referencing the same article.
Robert thanks for providing the link.
j,
type IX EPS has been used on a few PH projects in the NW.
As far as I'm aware, no semi-rigid mineral wool insulation is rated for sublab installation, but I don't see why it wouldn't work on a floating slab that had no floor drain or other plumbing penetrations that might be disturbed by slight settling (though I expect all settling will occur during the pour and not after).
它需要在矿物质羊毛顶部的蒸气屏障膜，以防止水泥浸润。
4英寸的平板重约50 psf死负荷，甚至40 psf的活载荷量仅为0.625 PSI（Roxul排水板在10％变形时的抗压强度为2.3 PSI，R值为4.3/英寸）。
Here are the minimum specs for the various types as published by the EPS Molders Association.
http://www.epsmolders.org/PDF_FILES/C578%20Chart.pdf
美国Passivhaus的一个gal告诉我，EPS的吸水“被证明是神话”。几年来，这里的一位超绝隔构造的构建器一直在浅霜保护的基础下使用25 psi EP（24英寸），我认为平板下有15 psi，没有“无问题”。不是暴露于冻结解冻循环任何子泡沫的祸根？
Robert,
Roxul的屋面保温更高的压缩机essive strength, 10-12 psi. It also has an optional facing that should keep out cement paste. The green cred may be compromised by embodied energy, because the material density is much higher than other mineral wool panels. R-value is also lower.
板栗，
David Pill used 4" EPS boards underneath his basement slab, although I couldn't find any mention about board density. See the third picture in this link:
//m.etiketa4.com/homes/energy-comes-sun-wind-and-earth-vermont-leed-platinum-home
We've found in the South where we have the occasional termite that the Performguard EPS (Expanded PS) with Borates from ACH is our best bet for under slab and in ground applications. The 1 lb. density is 15 PSI and the 2 lb. weighs in at 25 PSI. My understanding is that moisture retention is not a problem with this product. If I'm reading Alex WIlson's article correctly regarding the global warming potential of the Expanded Polystyrene within reason.
Martin - What is Type 9 EPS?
My understanding (from a recent conversation with the ACH rep) is that the ASTM C272 test for water retention is a 24 hour test, and therefore misrepresents their expanded foam product. Apparently the extruded foam boards will hold more water over a long period of time with a significant loss in R-value. Expanded polystryrene is more permeable, and drys faster. I like to use the Performguard 2 lb.density / 25 PSI over a vapor barrier under a slab, especially with a radiant slab.
We use blue billets of extruded for floating docks.
They do no soak up water.
我们建造了闭孔喷雾泡沫码头，并在20年后将它们全面登录。
If you use insulation under ground, get your drainage details right. Then use expanded foam with confidence.
That said I look forward to non fossil based solutions to in ground insulation.
Joe,
IX型EPS（或9型）的最小密度为1.8磅。每立方英尺，最小R值为每英寸4.2。许多分销商出售具有更高密度和R值的IX型EPS；我熟悉2.0密度EPS，R值为每英寸5。
More information here:
http://www.epsmolders.org/PDF_FILES/C578%20Chart%203.pdf
Water absorption by EPS is not a "myth", but the ASTM C 272 test involves 24 hour soaking.
In actual sub-grade conditions with well-drained soils, actual absorption is much less.
Type IX EPS is 1.8 pcf EPS with 25 psi compressive strength and R-4.2/inch.
Standard (type II) EPS has 30 times the water absorption of standard (25 psi) XPS.
通过标准ASTM测试，以下是蒸气渗透和吸水的比较：
Foamular 150 (15 psi) XPS
Water Absorption (% by volume max): 0.10
水蒸气渗透（perm max）：1.1
Type II EPS (15 psi)
Water Absorption (% by volume max): 3.0
Water Vapor Permeance (perm max): 3.5
Type IX EPS (25 psi)
吸水（数量最大为％）：2.0
Water Vapor Permeance (perm max): 2.0
马丁，
According to the chart you linked to (and any such specifications I've seen) EPS - even at 40 psi - does not offer more than R-4.2/inch.
Robert,
Thanks for the correction. You're right.
I just called Branch River Plastics for a clarification. The rep there, Kelly Smith, had told me that their Type IX EPS has an R-value of 5 per inch. After I called again, she admitted that the quoted R-value only occurs at 25°F -- in other words, the R-value was not tested according to the usual protocol required by the Federal R-value Rule, and is therefore not useful for comparing products.
At 25 degrees? Lacking way too much information to know what that means.
Delta t, one side at x and one side at y.
什么是三角洲？
What is x?
What is y?
What is 25 degrees f referring to?
Polystyrene rigid foam boards have the inverse quality of fiberglass (which diminishes in R-value as it gets colder).
Here is an ASTM chart of EPS and XPS specifications:
AJ Builder,
These are ASTM C 518 results. The convention for reporting ASTM C 518 results is to report the mean temperature.
According to the Federal R-Value Rule, "The tests must be done at a mean temperature of 75 deg. Fahrenheit." The test that Branch River Plastics reported was performed at a mean temperature of 25 degrees.
We install only eps for sub grade insul. Whether low density or high density depending on application and have never had complaints... from clients.
Here's what I found awhile back. Testing was done @ 72*
http://www.foam-control.com/downloads/brochure/Foam-Control-EPS-Water-Absorption-Facts.pdf
不幸的是,匿名提供的订单信息sters cannot be considered credible.
That "study" was based on a single anecdotal incident of a non-identified EPS and XPS that was dug up from an old building. It has been used by EPS manufacturers in the same way that a single Dow test on freeze-thaw resistance was used by them to "prove" the advantages of XPS.
Before you jump on your horse sir Robert, might you look throught the site.
我可以指出这项研究是由第三方完成的。水膨胀或化学挤出；想知道如果可以的话，哪个听起来更友好或绿色。