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Face it, EPS is the victim of years of a bad rap that just doesn’t have much basis in reality.
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bout 6 months ago I reported on a Canadian 2 year research program on expanded olystyrene (EPS) rigid foam board insulation (RFBI) below ground on a concrete foundation.
The full report has been published in the October 1999 issue of the Journal of Thermal Envelope & Building Science and is entitled: "In situ Performance of Expanded Molded Polystyrene in the Exterior Basement Insulations Systems (EIBS)."
Skeptics and believers with questions contact Mike Swinton at NRC Canada,
(613)993-9708. I do not know his e-mail address. GeneL
*Mike Swinton's e-mail address is: [email protected]. Patrick has doen a synopsis of this research report. Read it on the first part of this BT--the one just after Th Woodshed Tavern. GeneL.
*Extruded poly styrene rigid foam board insulation (RFBI)is not immune to water absorption. Under the right conditions: a high temperature differential. For example, place a 2x8 piece on water od of a swimming pool on a good hot sunny day. The high trmperature difference between the top and the bottom of the board, will cause it to absorb so much water thatit takes two persons to lift the sheet out of the pool. GeneL.
*Back in 1989 The Society for the Plastics Industry (SPI) sponsored a three year field study conducted by Twin City Testing Lasboratory in St. Paul, Minnesotas. Technicians installed 8 foot sheets of expanded polystyrene aro*und the below ground foundation of a building in St. Paul. Two types of ESP were tested: one with a desnity of 1 pcf and the other with a desnity of 1.5pcf. the RFBI sheets were buried 8 feet down into the earth.The results of the 3 year burial showed that ESP is but little affected by the freeze-thaw cycling, and the R-value dropped less than 10% over the three year test period.At about the same time the University of Minnesotsa did a 59 house field study of buried EPS. They found that there was less than a 1% moisture retention, and less than a 4% reduction in R-value. GeneL.
*Installing EPS below grade to gain some inslulation value is not worth the risk for future termite damage.The moisture that forms between the foam and foundation provides a easy path to your framing. I have yet to see anyway of certainty to stop this from occuring. RogerH
*Roger. Good point. But let's not confine it to EPS. This is true--termites--about any rigid foam board insulation (RFBI). Indeed, it can happen even with RFBI on the interior of the foundation wall. GeneL.
*.......well, this is certainly the horns of the dilema...the strategy i'm thinking of using on my next crawl space... is spraying the RFBI (man at last i found out what THAT was) with Bora-care and using Performgard as the RFBI....I'm also going to get all my foundation framing, including the garage walls, treated with Bora-care..insulating the floor always seems counter-intuitive unless we're using in floor radiant heat...I notice that National Fiber is using 100% Boric Acid and Borax in their Class 1 Cellulose spec... any of the studies talk about this as effective vermin control?
*Stopping termites is easy. Just move further north. Why do you guys down south in termite country insist on insulating below ground anyway? Gene you must have some cost vs benefit insight here?
*Face it, EPS is the victim of years of a bad rap that just doesn't have much basis in reality.
*MIKE.I'm at fault for not deciphering RFBI. I foolishly assumed that everybody on BT by now knows that it means Rigid foam Board Insultaion. I usually don't make that assumption. It may the the heady stuff on Whole house Humidification that got me.SCOTT. Oak Ridge National Laboratory (ORNL) has done considerable research on the benefits of insulating foundations. Tjhey released two publications in 1988: Assessment of the Energy Savings Potential of Building Foundation Research, and Building Foundation Design Handbook,However, the University of Minnesots is very much involved in the subject. see their web page. TEDD. Unfortunately you are correct. Perhaps the 3 studies I mentioned will help ESP to shed its u ndeserved bad name.GeneL.
*....got the rep from Branch River Foam meeting with me this afternoon... i'll give you the latest poop on Performguard....hah!
*Gentlemen. For those of you who like a copy of the National Research Council Canada, study casll thomas /Greeley's office at BASF 800-526-1072 extension 3908. And also ask him for a copy of the Minnesot Study. For Canadians his e-mail is [email protected]. I would imagine Canadians might be able to get a free copy from NRC. GeneL.