Gloved hand pulling away a piece of drywall heavily covered in mold. A representative photo of the task, not a record of work at any particular property.
How it unfolded
Illustrative example. Not a real job or customer.
A family notices that their basement guest bedroom smells musty from about June through September but seems fine in winter. A built-in bookcase covers most of the exterior wall below the egress window.
- The owners pull books off the lowest shelf and find a dark line along the baseboard behind the bookcase.
- A remediation contractor's moisture readings show the wall is wet from the floor to about knee height beneath the window.
- Walking the yard with the sprinklers running reveals a rotor head spraying directly into the window well.
- The well's gravel bottom is clogged with soil and leaves, so water pools against the window frame and seeps around it.
- The irrigation contractor relocates the head and adjusts the zone, and the window well is cleaned out and its drain checked.
- Inside, the bookcase is removed, the room is contained, and wet drywall and insulation are cut out, cleaned and dried before rebuilding.
The following summer the room stays dry, which the owners confirm with a hygrometer reading recorded each week.
Why the seasonal pattern was the key clue
Note when it happens
A problem that appears only during irrigation season points outside, not to plumbing that runs year-round.
Watch the zones run
Running each zone while someone watches the house is the quickest way to find misaimed heads.
Inspect the well
Window wells need to drain; debris and soil buildup can turn them into small ponds against the window.
Check behind built-ins
Fixed furniture on exterior walls hides staining; remove a shelf or panel to look.
Common questions
- Could the built-in bookcase have been saved?
- Often a built-in can be detached, cleaned and reinstalled if its back panel and base were not soaked for long. Particleboard parts that swelled or show growth on the back are usually replaced. Ask the remediation contractor to look at both sides before deciding.
- Why did the room seem fine in winter?
- Once the irrigation system was shut down and blown out in the fall, the window well stopped filling and the wall slowly dried. The growth stayed dormant until the sprinklers started again in spring. A seasonal pattern like that is one of the strongest hints that the water is coming from outside.
- Does every egress window well need a drain?
- Wells are generally built to drain, either to a perimeter drain or into gravel below. Requirements vary, so ask a contractor and your building department what applies to your house.
General information for Cherry Hills Village, not a quote or professional advice. In an emergency, call 911.