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Winterplace at Okemo Pool and Spa

Case Study for High-Moisture Environments

In the late fall of 1998, Mr. John Neal, the Winterplace facilities manager, contacted FOAM-TECH, primarily to resolve the leaks he attributed to ice dams on the pool and spa roofs. had heard of our work with ice dam remediation at other ski-area complexes around the Okemo Resort. The leaks were so severe that they had planned to remove the skylights because they believed that many of the problems with melting snow, roof leaks, and condensation resulted from the skylights and their flashing.  During our inspection of the building, we discovered that severe mold and mildew problems existed in the attics.

We also determined that the leakage only occurred in the winter. The ice dam and attic moisture symptoms were so severe that we proposed to address those two problems and then reassess the skylight performance.   This would reduce costs and possibly save the natural light the skylights provided. The overall plan included managing how the HVAC systems were insulated and sealed where they passed through the attics, as well as installing an air leakage and vapor control materials at the scissors truss ceiling of the Pool and the roof slopes of the Spa portion of the building.  The building envelope work included the skylight wells.

After the first round of repair work, which included testing the air barrier, the roof leaks had stopped and the skylights were able to be kept as an aesthetic feature of the building.   There was only one localized melt area (and related ice formation) remaining on the roof.  Follow-up testing revealed that the make-up air supply for the large hot water boiler still originated in the attic, rather than extending to the outside. This was only a problem when the boiler was not firing and the stack-effect of the building would reverse the normally inward flow of cold outside combustion air, pumping hot, moist pool room air into the attic.  Since this was addressed, the roof and attic have been performing well. Only the clean-up of the mold and mildew in the pool attic remains to be completed.
The “before” photo of the roof melt pattern on the spa indicates the warming of roof surface caused by heating and ventilating equipment in the attic.  The melt area starts just above the ceiling insulation.

The “after” photo shows that insulating the roof slope instead of the flat ceiling in this attic brought the mechanical equipment “inside” the thermal envelope and stopped the roof melt and ice dams.

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