Condensation Potential in High Thermal Performance Walls. Hot, Humid Summer Climate.
Abstract
To observe actual moisture patterns and the potential for condensation due to long periods of air conditioning in a hot, humid climate, a test structure was constructed near Gulfport, Mississippi, for exposure of eight types of insulated wall panels at controlled indoor conditions and typical outdoor weather conditions. Panels were instrumented with moisture sensors and tested without (Phase 1) and with (Phase 2) penetrations (electrical outlets) in the indoor surface. There was no sustained condensation in any of the walls during either winter season. One type of high thermal performance wall had sustained condensation during both summers, but the wall dried out as the weather became cooler, and moisture content of framing never exceeded 17 percent. Low-permeance sheathing appeared to provide resistance to the buildup of moisture during summer in walls with high overall 'R' values. Penetrating the walls with electrical outlets resulted in slightly higher moisture levels in all of the walls throughout the year. This paper should be useful to building designers, builders, and building code officials in establishing vapor retarder requirements for walls. Keywords: Condensation, moisture control, vapor retarder, air leakage, wood-frame walls, foam sheathing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1985
- Accession Number
- ADA158002
Entities
People
- G. E. Sherwood
Organizations
- Forest Products Laboratory