Waterproofing the cellar

The June monsoons appear to be over and work resumed today—a week later than we’d hoped. Vilen Construction is back on site to waterproof the foundation walls around the cellar. We’re using a material not routinely used to waterproof residential foundations in this area; Volclay panels are a “biodegradable kraft board filled with high-swelling, sodium bentonite.” As the Volclay absorbs water it gradually expands several (as much as 15) times its current size, filling in air pockets and creating a clay-like, low-permeable seal around the foundation.

To be sure, there are other ways to waterproof the foundation, but we really like the environmentally-friendly touch this provides. [And coincidentally, the Big Horn Bentonite used in our installation is mined in an area of northern Wyoming and south central Montana we know well, ‘just down the road’ from where our Montana kids live!]

Looking back at the previous couple of weeks, between seven and eight inches of rain fell over the area June 20-25; for us it meant having to wait most of the past week for things to dry out—but for the area it meant flash flooding, a county-wide state of emergency, washed out bridges and culverts just around the bend, and a slightly-rechanneled trout stream and Root River adjacent to our property. We’re very grateful to have escaped with simply having to wait it out.



Lanesboro, Minnesota
Climate Zone 6 (cold/moist)
Latitude: 43° 44' 18'' N
Longitude: 91° 54' 48'' W

House Size

Net Treated Floor Area: 1,514 SF
Gross Square Footage (House only): 2,210 SF

Building Envelope

Roof: R-99
Wall: R-61
Ground: R-53

Windows & Doors

Glazing: U-0.10 BTU / hour / sq. ft.
Solar Heat Gain Coefficient (SHGC): 0.48”
Frame: U-0.19 BTU / hour / sq. ft.

Modeled Performance

Specific Primary Energy Demand (Source Energy Demand): 12.1 kBTU / sq. ft. / year

Specific Space Heat Demand: 7.0 kBTU/sq. ft. / year

Peak Heating Load: 7,047 BTU / hour

Space Cooling Demand: 0.44 kBTU / sq. ft. / year

Peak Cooling Load: 3,625 BTU / hour

Pressure Test Goal: Whole House Air Changes Per Hour (ACH) = 0.4 ACH 50


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