| Title |
Moisture Stability of Lightweight Wood Frame Constructions by Vapor Barrier in Energy Conservation in Buildings |
| Authors |
김민주(Kim, Minju) ; 류현진(Ryu, Hyunjin) ; 김석환(Kim, Sughwan) |
| DOI |
https://doi.org/10.5659/JAIK.2025.41.3.269 |
| Keywords |
Vapor Barrier; Water Vapour Diffusion-equivalent Air Layer Thickness; Lightweight Wood Frame Construction; Moisture Stability; Energy Conservation in Buildings |
| Abstract |
Lightweight wood frame constructions have been being built in Korea with increasing demand for eco-friendly, low-carbon buildings. A vapor
barrier in these constructions are essential for protecting from wood decay ensuring durability. However, definition of vapor barrier and
waterproof vapor permeable membrane are often conflated, so it results in many moisture problems in the constructions. This study evaluates
the moisture stability of a standard configuration of lightwood frame construction across Korean climates, specifically Daegwallyeong, Seoul,
Busan, and Jeju, using eight types of materials approved as vapor barrier in Energy Conservation in Buildings. Five evaluation criteria of
DIN 4108-3 were used. In terms of total moisture content, equilibrium within 10 years was achieved in all configurations and locations.
Short-term OSB decay was found in a year when vapor barriers with low Sd-values (≤1.3 m in Daegwallyeong, ≤0.3 m in Seoul) used,
and when non-vapor barrier was used in Busan and Jeju. Long-term OSB decay evaluation indicats that vapor barriers with Sd ≤ 0.3 m are
unsuitable in all climates, while the ZIP System®(Sd = 2.5 m) is inadequate for Daegwallyeong. Interstitial condensation on the insulation
layer was found in Daegwallyeong and Seoul with the vapor barrier of Sd ≤ 0.3 m in winter. The possibility of mould growth increases
across all climates if a vapor barrier with an Sd-value of 0.3 m or lower is applied. It was observed even with vapor barrier having
Sd-values of up to 2.5 m in Daegwallyeong. Thermal transmittance shows no decline over the ten years. Moisture problems in lightweight
wood frame constructions were found in Daegwallyeong due to the vapor barriers with Sd-values of 2.5 m or below. For Seoul, Busan and
Jeju, no moisture problems were found if vapor barriers with Sd-values of 1.3 m or higher were applied. However, as this study focused
only on the current vapor barrier standards, a further detailed study is required for the range of Sd-value from 0.5 m to 10 m. Additionally,
for lightweight wood-frame constructions with rainscreen applications, it is critical to establish vapor barrier performance standards adapted to
each climate zone in Korea. |