Building Science Puzzles: Wine Room Weirdness—Part 1 – GreenBuildingAdvisor

Building Matters

Test your skills as a building science investigator. What’s causing the moisture issue in the wine room?

In the Building Science Puzzle series, the GBA audience is part of the building science investigation team looking into a building science problem. Each “puzzle” consists of at least two posts. The first discusses the reasons for the investigation, explains the process, and shares the observations, data, and other findings that were collected. The second post, which is published a week later, details the answer, or at least a hypothesis of what is going on. There may be additional clues to the puzzle in the comments section below as the author responds to members’ questions and comments, so be sure to check regularly.

Water where it shouldn’t be

Your clients call you one August day to ask if you can come look at an odd problem. You built a wine room in their house near Washington, D.C. (climate zone 4) the previous year. They have had some brown liquid dripping down the wall at the thermostat. When they clean it off it comes back, and they’re concerned about it.

The wine room is an interior room in a one-story house of slab-on-grade construction. It’s about 8 ft. by 10 ft., with a tile floor and gypsum board walls and ceiling. An exterior-type door with double glazing, full weatherstripping, and a threshold and sweep completes the enclosure. A ductless minisplit-type indoor HVAC section is connected to a specialty wine refrigeration outdoor unit. The thermostat is set to 57°F.

Inside the room there’s also some staining in the glass dome of the ceiling light, and some around the door trim below the interior HVAC machine.

Knowing that HVAC systems create condensation as part of their normal operation, and that this sometimes leaks for one reason or another, you take the door trim and HVAC system covers off to see if…