A room that is always evaporating

Every open water surface releases vapor, and a heated indoor pool or spa releases a lot of it. In a dry climate like the Front Range, it is easy to assume the air will absorb it. Inside a closed room it cannot, and the moisture has to be removed mechanically, usually by a dedicated pool dehumidification unit sized for the water area, temperature and use.

When that equipment is undersized, poorly maintained or turned down to save energy, humidity climbs. Warm, humid air then finds the coldest surfaces in the room: window frames, skylights, exterior walls and the ceiling. In winter, those surfaces can be cold enough for condensation to run down the glass and soak sills and drywall. Moist air can also leak through ceiling penetrations into an attic, where it condenses on the roof sheathing.

Points that matter in a pool room

Pool covers
Covering the water when not in use sharply reduces evaporation
Room pressure
Pool rooms are commonly kept slightly negative so humid air does not push into the house
Water temperature
Warmer water evaporates faster, raising the dehumidification load
Glass and frames
The first place condensation appears in cold weather
Chlorinated air
Can corrode equipment and fasteners, which makes maintenance more important

How a pool room problem tends to develop

First winter of trouble
Heavy condensation on windows in the mornings; sills stay wet.
Weeks later
Black spots on caulk, window returns and the lower edge of drywall near the glass.
Over a season
Paint peels on the ceiling; a musty odor drifts into the adjoining hallway or guest suite.
Longer term
Attic sheathing above the room darkens, and wood trim around doors swells.

Things to have evaluated together

Remediation inside a pool room is wasted if the humidity source keeps running, so bring the right trades in at the same time.

  • Dehumidification unit: sizing, filters, coil, drain and set points, checked by a mechanical contractor familiar with pool systems
  • Air leakage from the room into the attic and adjoining spaces
  • Window and skylight condition, including frames and seals
  • Whether a pool cover is used consistently
  • Extent of growth on drywall, ceiling and trim, mapped with moisture readings
  • Condition of the vapor barrier in walls and ceiling, if it can be checked

Common questions

Is mold in a pool room different from mold elsewhere?
The remediation steps are the same: contain, remove what cannot be cleaned, clean and dry. The difference is that the humidity load never stops, so the mechanical fix has to be solid before rebuilding.

General information for Cherry Hills Village, not a quote or professional advice. In an emergency, call 911.