Musty Smell in an Older Home

Mold gives off compounds with an earthy, musty smell. You often smell it before you see it, especially when mold grows inside walls, under floors or behind cabinets.

Check under kitchen and bathroom sinks, around toilets and tubs, behind the washer, near the water heater, closets on exterior walls, ceilings below flat roofs and the base of walls on the irrigated side of the house.

Galvanized pipe leaks inside walls, old cooler openings in ceilings, roof leaks under flat roofs and irrigation water wicking into walls are common moisture sources in mid-century homes.

A basic moisture meter shows damp spots in walls and floors. A professional thermal camera can show cooler, wet areas behind plaster without opening it.

A small patch, a few square feet on a hard surface, can be cleaned with detergent and water while wearing gloves, eye protection and an N-95. Dry the area and watch for return.

Call a professional for larger areas, mold inside walls or ceilings, mold after sewage or irrigation water, or a smell you cannot trace; see mold inspection and removal.

Removing mold without fixing the leak does not last. Find the pipe, roof, irrigation or drain problem and fix it first.

Children, older adults and people with asthma or allergies are most sensitive. The EPA mold guidance has background.

Dry any leak within 24 to 48 hours, use bathroom fans, keep irrigation water away from walls and fix drips quickly.

Closets on exterior walls stay cooler and can collect moisture, especially if stuffed with clothes and boxes that block airflow. Bathrooms without working exhaust fans hold humidity after every shower. Clearing closets, adding a fan and fixing small drips often removes the smell for good.

Some older homes still have the ceiling opening where an evaporative cooler once blew in. If the roof patch above it leaks, mold can grow around the opening. A musty smell near an old vent is worth checking.

If the musty smell appears when the air conditioning runs, the source may be the air handler, its drain pan or the ducts. An HVAC technician can check for standing water or growth.

A few older homes have raised wood floors over a crawl space instead of a slab. Leaks and poor ventilation under the floor can cause musty smells throughout the house. A provider can check the crawl space safely.

Musty smell you cannot trace? Call (602) 878-3892 for a local provider who can find the moisture.

If the home had a leak months or years ago that was not dried properly, mold may have grown behind the repaired wall. A smell that lingers near an old repair is worth checking with a meter.

Once the source is fixed and moldy material is removed, the smell should fade within days as the area dries. If it lingers, moisture is still present.

Spraying bleach on plaster or drywall, painting over stains, running fans across moldy areas and putting off fixing the leak all make mold worse or hide it until it spreads.

Follow the smell to the moisture, fix it and the smell goes with it.

A musty smell in a mid-century home is not something to ignore or cover with air fresheners. It is the house telling you that moisture is getting in somewhere. Follow the smell, find the source, fix it and dry the area, and remove anything that has grown mold. Most of the time the smell disappears once the moisture is gone.

If the smell is strongest in one spot, start there. Check below and above it, behind nearby cabinets and along the base of nearby walls with a meter. If you cannot find the source, a provider with a thermal camera usually can, without tearing walls apart. Once the moisture is fixed and moldy material removed, the smell fades quickly.

If you cannot find the source yourself, call (602) 878-3892 for a local provider who can check moisture with meters and a thermal camera. Most hidden sources are found within a single visit. Act early, always.

A musty smell is a moisture clue. Follow it, fix the source, clean small patches and call for anything larger or hidden.

Questions about musty smell in an older home? Call (602) 878-3892 to reach a local North Central Phoenix provider, 24 hours a day.