Ventilation Modified In Hotel,

Menlo Park, case study

Initially Eastman Roofing & Waterproofing was called to estimate a repair for a roof leak. After speaking with the chief facilities engineer and analyzing theinadequate ventilation caused dry rot in this Menlo Park roof structure, we informed them it was not a roof leak–Rather a design flaw – inadequate ventilation coupled with “vapor drive” (Moisture vapor will naturally move from the warm side of a wall to the cooler side) causing dry rot in the building.

Some of the unvented areas were designed to be firewalls and could not be vented. To eliminate the vapor drive in these areas, spray foam insulation was applied to fill the space between the roof deck and dry wall (the “firewall”).

Some of the areas did not have adequate intake and some had no air space above the insulation at areas that were covered by a cathedral ceiling. Vapor drive caused extensive dry rot. Additional intake ventilation was installed and a 1-inch air space was created above the insulation to achieve proper air flow, which resulted in elimination of the vapor drive problem. The solution also vented the attic space correctly, which kept the inside space cooler, reduced air conditioning costs, and qualified the roof for the manufacturer’s long-term warranty.