Guides
Moisture and mold guides
Humidity, condensation and smells, and the mold that follows them: how to tell what you’re looking at, what you can clean yourself and when to call a professional.
Humidity and condensation
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Start here
Basement humidity: ideal levels and how to measure
Keep basement humidity below 60%, ideally 30–50%. How to measure it properly, what your readings mean and what to do next.
Read the guide: Basement humidity: ideal levels and how to measure -
Basement dehumidifiers: size, drainage and placement
How to size a basement dehumidifier with ENERGY STAR’s chart, why ratings changed in 2019, and how to drain and set it so it actually works.
Read the guide: Basement dehumidifiers: size, drainage and placement -
Dew point and condensation on basement walls
Check whether a basement wall, pipe or floor will condense with your readings, and how to tell condensation from a leak.
Read the guide: Dew point and condensation on basement walls -
Musty and sewer smells in the basement
How to tell a musty smell from a sewer smell, where each one usually comes from, and what actually gets rid of it.
Read the guide: Musty and sewer smells in the basement
Mold
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Mold in basements: causes, cleanup and when to call a pro
Why basement mold means a moisture problem, how to clean small areas safely, and when a basement mold job needs a professional.
Read the guide: Mold in basements: causes, cleanup and when to call a pro -
Black mold: what it is, what it isn’t and what to do first
"Black mold" isn’t a species, and color won’t tell you the risk. How to tell mold from soot and stains, what to do first and when to call a pro.
Read the guide: Black mold: what it is, what it isn’t and what to do first -
White mold, efflorescence or mildew? How to tell what’s on your basement wall
White fuzz on a basement wall can be salt, mold or "mildew." How to tell them apart by surface, light and a drop of water, and what each one means.
Read the guide: White mold, efflorescence or mildew? How to tell what’s on your basement wall -
Mold on wood: joists, subfloors and sill plates
Mold on floor joists or a subfloor is usually on the surface, but rot isn’t. How to tell them apart, what moisture readings mean and when to call a pro.
Read the guide: Mold on wood: joists, subfloors and sill plates -
Mold inspection and testing: when it’s worth it
When a mold inspection or lab test is worth paying for, what it should include, what it costs, and why home test kits tell you little.
Read the guide: Mold inspection and testing: when it’s worth it -
Mold remediation cost in crawl spaces and basements
What mold remediation costs in basements and crawl spaces, what a complete job includes, and the red flags in a quote. Prices from Virginia jobs, 2026.
Read the guide: Mold remediation cost in crawl spaces and basements
