Pre-Listing Mold and Moisture Checks for Sellers

A pre-listing mold inspection is a moisture and mold check of your home done before it goes on the market, so you find problems before a buyer's inspector does. It covers the attic, basement, crawlspace and the areas around plumbing, using a flashlight, a moisture meter and often a thermal camera. Sellers who do it get to fix issues on their own schedule and avoid a surprise in the middle of a deal.

Why check before listing

Once an offer is conditional on inspection, every finding lands on a deadline. You have a few days, the buyer is nervous and the repair gets negotiated at its most expensive. The same finding six weeks earlier is an ordinary maintenance job. Checking early also lets you correct the cause, give the area time to dry and have your documents ready when the listing goes live.

Where to look: a seller's walk-through

• Attic: lift the hatch and shine a light on the underside of the roof deck. Look for dark staining, especially on the north side and near the eaves. Check that bath fan ducts run to the outside.
• Basement walls and floor: look at the bottom 30 cm of every wall, the corners, and behind stored boxes and furniture. White powdery deposits on concrete mean water has been moving through it.
• Finished basement: press on baseboards and the bottom of the drywall. Swollen, soft or stained material means moisture behind it.
• Crawlspace: check for bare soil, wet or fallen insulation and a musty smell.
• Under sinks and behind toilets: look for stains, warped cabinet floors and slow drips at shutoff valves.
• Water heater, laundry and furnace: rust at the base, stains on the floor, a leaking or disconnected condensate line.
• Windows: black growth on sills and frames from winter condensation.
• Bathrooms: the ceiling above the shower, the caulking, and whether the fan actually pulls air.
• Outside: downspouts that end at the foundation, soil sloping toward the house, window wells full of leaves.

What a professional pre-listing mold inspection adds

Your eyes and nose catch the obvious. A professional check finds what is hidden and measures it. A thermal camera shows temperature patterns that point to damp areas behind drywall and under floors. A moisture meter then confirms whether the material is actually wet, and how wet. You end up with photos, readings and a plain list of what needs attention. Our leak detection and moisture inspection runs $249 to $549. It is not a full home inspection. It does not cover wiring, the furnace or the roof shingles, so some sellers book both.

When to do it

Four to six weeks before listing is comfortable. That leaves time to book a repair, let materials dry and have a contractor repaint or replace drywall if anything was opened. If you are listing in spring, look in the attic during a cold spell in winter, when frost and condensation on the sheathing are easiest to see. Check the basement after a heavy rain or during the spring thaw, when the clay-heavy soil around London is saturated and foundations are under the most pressure.

Simple fixes worth doing before the photos

• Extend downspouts well away from the foundation.
• Reconnect or reroute bathroom fan ducts so they discharge outside.
• Pull insulation back from the soffit vents.
• Run a dehumidifier in the basement through the humid months and make sure it drains properly.
• Replace failed caulking around tubs and showers.
• Move stored cardboard and fabric off the basement floor and away from the walls.
• Replace old rubber washing machine hoses with braided ones.

What to do with the results

If the check comes back clean, keep the report. It is a useful thing to hand a buyer's agent. If it finds mold or wet materials, get a written quote, have the cause corrected and the growth removed, and keep the clearance report with its before and after photos. Most attic jobs here run $2,300 to $6,500 and most basement jobs run $1,200 to $9,500. What you have to tell buyers about past problems is a question for your realtor and lawyer. A documented repair is a far easier thing to talk about than an open problem.

Start this weekend with a flashlight and your phone camera. Photograph anything dark, damp or soft and note the room. Within an hour you will know whether you need a second opinion.

Common questions