Basement flooring
The best basement floor is the one chosen after the slab has been tested, not before.
Concrete in contact with soil gives off moisture, and it does so invisibly. A floor that is glued to a damp slab fails slowly, with curling edges, a musty smell and a smooth board that turns up at the seams. That is why the slab is tested before the floor is chosen.
Test the slab first
Moisture in a slab is measured, not guessed. Flooring makers publish limits for their products, and those limits are tied to standard test methods: in-slab relative humidity probes (ASTM F2170) or a calcium chloride test of vapor emission (ASTM F1869). The plastic-sheet-taped-to-the-floor trick is a rough check of whether there is a problem, not a measurement of how big it is. Each product's installation instructions tie it to a test result, so ask to see the maker's requirements before you buy.
If the slab fails the test,
the answer is not to use a stronger glue. It is to fix the source of the moisture, or to choose a system that sits above the slab with an air gap or a moisture layer.
Which floors tolerate the below-grade world
| Floor | Strength | Watch for |
|---|---|---|
| Tile on a decoupling membrane | Handles moisture and water well; easy to clean | Cold underfoot unless warmed; the slab must be flat |
| Luxury vinyl plank or tile | Water-resistant surface, forgiving of small moisture | Moisture trapped below some products; follow the maker's slab limits |
| Dimpled subfloor panels with a top floor | Warmer, with a built-in air gap and moisture layer | Costs floor-to-ceiling height |
| Carpet tile | Warm and replaceable one square at a time | A damp slab will grow mildew under it |
| Sealed or epoxy-coated concrete | Low height; good for gyms, workshops and storage | Moisture below the coating can lift it; surface prep matters |
| Solid hardwood | Not suited to below-grade rooms | It swells and cups; engineered products have limits too |
Not sure what applies to your house?
Send photos of your basement with an estimate request, or call 847.962.4689. Robert will tell you what he would look at first.
What a floor does to your ceiling
Every layer on the slab comes out of the room's height. In a basement where a bedroom needs a minimum ceiling height, the floor system is part of that calculation, so it is decided with the ceiling and not after it.
Leave a way in to the drain
Most older basements have a floor drain, and some have a cleanout. A finished floor that buries either is a future problem. Plan a removable cover or a floor that can be opened.
Questions
Can I put hardwood in a basement?
Solid hardwood is not suited to a below-grade room. Some engineered products have limits that depend on the slab, so check the maker's requirements before you buy.
Is a rug on bare concrete enough?
Sometimes it is fine for a storage or play area. Under furniture, a rug can trap moisture against the slab. Lift a corner now and then.
Homes where this comes up
Keep reading
Tell Robert about your project.
Call, email or send an estimate request with photos. You deal directly with the person running your job. Robert replies within 2 business days.