Arkansas HVACR NewsMagazine September 2020

S tate, National, Chapter News Tech News

Dew point in an attic during mild conditions can come as a surprise. An ambient air temperature in a 110° attic with 75 percent humidity will produce a dew point of l00°, making it easy to see how condensation can form on equipment cabinets and surface of ducts. In some instances, these conditions can compromise water-based sealing components. CONSTRUCTION PRIOR TO 1950 Crawl spaces must be addressed when involved in remodeling projects that incorporate pier and beam construction. Existing crawl space ventilation must be abandoned. Grade areas should be covered with a vapor barrier and ballasted to hold the barrier in place during wet weather events. (See Figure, 5 and 5a.) When graded areas are left open, the moisture in the ground will migrate through construction materials to drier space. A portion of the moisture passing through construction materials will be trapped and cause material to swell or warp and floor or painted finishes to lift. Simply sealing below the floor is not enough; moisture will attack framing and the support system will suffer damage. Original designs of pier and beam construction enabled the entire structure to breathe. Alter that design in

part or completely, the structure is placed at risk.

(Continued on next page)