NorthernStar, DOE, Foundations & Basements Recap

Thanks to Michael Anschel we are able to provide the second day of the NorthernStar Conference which was covering foundations & basements on this day. (The first day & more information) This event was composed of individuals from DOE, Verified Green & the University of Minnesota among others working on creating better guidelines for the Northern Climate zones. With that said, many of the items discussed do apply to basements here in the south also.

• How complex are the calculations for hydrothermal conditions in foundations? So complex they crashed a CRAY! (hmmm – it couldn’t have been the actual programming, nah, programmers always blame the hardware)
• Study found bulk water in XPS…fully saturated… Just from vapor transfer
• Convective loop on a basement wall is opposite from what you might think. Warm at the bottom and cool at the top.
• Four year study of XPS and EPS showed saturation of XPS and a total failure of EPS.
• Pressure gradient trumps vapor gradient in below grade condition. Ultimately vapor pressure wins.
• Hybrid insulation and bulk water assemblies. BSC is working on ideas.
• Insulating outside the foundation is the best way to insulate a basement. Period.
• Insulating the exterior of the foundation eliminates the condensation surface. Like removing the third rail.
• Kota – “you are ventilating your house through your basement”
• Insulating the ceiling in your basement is just never a good idea. Almost impossible to air-seal, and energy losses not recaptured. (hmmm let’s not forget crawl spaces either)
• Wow! Deep energy retrofit that included insulated the ceiling tested out with over 1400cfm at 50! Total failure! Haha.
• Soil is at 100% relative humidity. Never forget that. Concrete is highly porous. Never forget that either.
• Priorities for dealing with water: air, vapor, capillary, convection, drainage…. The list goes on and on and on…
• Earth heaves in the direction of the heat loss.
• Adfreezing. Soil bonds to concrete and the pulls the concrete when it heaves. Not possible on insulated structures. Whew!
• AVID system (air/vapor/insulation/drainage) : interior drainage with half height insulation Goldberg & Farkas 2004 using open cell foam on the interior, good performance, low moisture accumulation. Frost in Zone 7 is possible
• WTF!? Seriously BSC.. Jack up the house to “insert” a vapor barrier between the rim and the foundation? Get real.
• Dimple face sheathing must be air sealed at the top otherwise high humidity air is directed directly to the wood joists.
• Drain tile and sump must be connected to dimple sheeting.
• Damp proofing is not water proofing.
• CMUs are moisture chimneys. You MUST seal the top of the blocks.
• …If the basement is damp/wet, the solution needs drain plane, drain tile, and sump.
• Finishing your basement may be the riskiest thing you can do.
• Insulating your rim joist means it stays colder for longer.. Less drying potential…
• » any basement (below grade). The rim joist is a weak point and we have almost no good data on moisture accumulation in the rim.
• If your slab is not insulated below, putting carpet down is the worst thing you can do.
• The moisture in the soil will condense under the carpet. Mold. Gross. Unhealthy.
• » The best solution I’ve seen is peel and stick over the block, under the rim, tied to drain tile, then insulate.
• Research demonstrates once again that we allow things to be done to our homes that should never be allowed.
• Wow! Uninsulated slab on grade home had heating cost of $2000. Insulated slab was only $300.
• In mixed humid climates unvented crawlspaces radically outperform vented. Of course in cold climes, we must vent!
• Intense debate on foundation wall drawing here. Interesting to see how disconnected the researchers are from common practice
• Firm statement for researchers. The code approved basement finishing detail is not safe, not sound, not acceptable.
• We need to have a study on flash and batt. Too variable, too inconsistent, and too many unknowns for it to be used.
• You can tell people a hundred times that vinyl flooring and wallpaper is not compatible with Air Conditioning, and they still install it.
• We need to end the practice of blowing cellulose into old stucco homes. Picture of yet another energy efficiency victim http://img.ly/au6E
• Solutions that require “perfect installation” are not solutions. Period.
• The fact that there is no consensus on how to finish a basement in this group should make remodelers and homeowners very nervous.
• All of the good solutions we have for foundations are expensive, but American consumers don’t value quality construction.
• This conversation has gotten radically depressing. Builders and remodelers won’t build it right. Consumers won’t pay. So why even bother?
• Thanks for all the RTs today… Important info for our most valuable asset; our homes.

Once again I would like to thank Michael for not only tweeting this, but giving us this opportunity to provide the transcript so you may get a better feeling for where the industry is now & make better decisions as a result.

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