BPI's June Stump the Chump!

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Permalink Reply by Mike Kandel on July 16, 2012 at 7:06am

Congratulations to Kevin Hanlon of Horizon RES NH LLC in Concord, NH for providing the correct answer and proper evaluation of last month's stumper! There were a number of great responses, but Kevin's illustrates the most comprehensive understanding of the problem. As a reminder, Ken Tohinaka of the Vermont Energy Investment Corporation provided this tricky scenario (scroll down) and asked readers to evaluate the use of a bio-mass boiler and additional insulation in reducing ice-dams and increasing the building's efficiency.

Kevin suggests that a bio-mass boiler "wouldn't make the building more efficient, it would just be a heating system that would be more efficient at contributing to heat loss and ice dams."

Kevin also notes that additional insulation might not solve the problem. Additional insulation "is not the answer unless the pressure barrier of the ceiling assembly of the additions was fixed first, and proven to be complete and effective."

Finally, Kevin explains that a visual inspection, blower door pressure test across the attic, and a pre and post data logging exercise would be good ways to determine the cause of the ice dams and ultimately determine an appropriate solution.

Ken adds that it is important to recognize "the trombe wall which extends above the attic floor plane, the wood shop vacuum, and the auto shop ventilation systems that depressurize the additions."

"The streaking in the fiberglass batts, particularly at the juncture of the additions, indicates that heated air from the classrooms is being drawn into the main attic by the shop equipment, adding to the heating from the trombe wall extending above the attic floor plane. The air is then pulled into the shops by their mechanical equipment through insulation and dropped ceilings."