Detecting Basement Mold
Careful inspection is required to find basement mold. Look for any signs of water intrusion. Check all pipes that pass through the basement ceiling from the floor above. Look around each pipe for indications of leaks, such as wood discoloration or stains on the basement floor. Any discoloration of the wood surrounding any plumbing indicates a water problem.
Examine the floor joists that support the house and floor above the basement. Follow each joist its entire length, looking for wood discoloration. Examine all basement walls and the entire floor. Moisture is easily detected in cinderblock and concrete floors. If the basement floor has water stains, or if the walls are excessively damp, the cause must be determined. Most leaks are due to groundwater seeping in from the outside. Gutter drainage problems are the cause most of the time, or it may be due to a negative ground slope, directing the groundwater toward the home instead of away from it.
Sump-pump drains are pretty much an open invitation for mold. Many of these pumps are seated in wet wells, basically water in a hole, and that moisture increases the chances of mold. If the hole is dry and is intended as a safeguard against minor flooding, there may not be a basement mold problem.
In an unfinished basement, items leaning up against the foundation walls or resting directly on the floor are cooled in warm weather by the concrete. Moisture can then condense on these surfaces and microorganisms will grow. We often find mold growth on the bottoms of cardboard boxes resting on a basement floor. Sometimes, if the floor has been very damp, when you lift the box its imprint will be left in mold, or the bottom of the box will be so deteriorated that it sticks to the concrete.
Mold in Finished Basements
When basements are finished with carpeting, paneling, and other materials, inspecting for basement mold can be more complicated because the signs are hidden. The first clue is a musty, mildew smell. If unwanted water or home moisture has entered the space, mold spores may be growing, fed by everything from carpets and drywall to wood or upholstered furniture, and anything else stored in the area.
Flooring and Basement Mold
Carpeting should be carefully considered on basement floors. The problem with carpet in a basement is that organic materials eventually settle in the carpet and act as a food source for mold when the moisture level rises. In finished below-grade rooms, carpeting and pad that rest on the concrete floor can be soaked by floor flooding or dampened by water diffusing through the concrete if it is not sealed by resilient tile or vinyl, or by water vapor from the air. This leads to mold and mite infestations.
A synthetic carpet with a porous carpet pad offers the advantage of allowing moisture vapor to migrate through and into the air where it can be ventilated or dehumidified. Vinyl flooring or resilient tile is durable and can be cleaned more easily, but it also acts as a vapor barrier when placed over a concrete slab. Typically, a concrete slab will have consistent vapor pressure trying to migrate out of the concrete into the drier surrounding air.
Walls and Ceilings in Finished Basements
Finished walls, particularly near the concrete floor, are also cooled by heat loss to the foundation, and they too can become colonized with basement mold. Microfungi can grow on dust, often in an unseen film on basement wall paneling and the unfinished surfaces of wooden furniture, and hidden in cushions (especially where food was spilled), upholstery, and carpeting. And if the relative humidity is high, white acoustical ceiling tiles can occasionally be covered with barely visible mold colonies. When this happens, as with any unseen fungal growth, the room can have a ubiquitous musty smell, even when the area looks clean.
Basements are often used as playrooms, studies, exercise rooms, bedrooms, and home theaters. These rooms are often beautifully decorated and all too often infested with concealed microfungi. Many of these rooms were designed for leisure activities, so people spent hours there, breathing in spores. If you exercise in a room with basement mold, your exposure is even greater because of your increased respiration rate. Read the Centers for Disease Control and Prevention’s Facts about Mold and Dampness.