Choosing the right underlayment for a concrete subfloor is critical in basements and slab on grade homes where moisture is a real concern. Why? Because concrete is porous. Over time moisture will wick it's way through the concrete and into your home. This is why the right subfloor system is necessary to protect your flooring. In case your wondering, NO Wood subfloors are almost never used in basements or slab-on-grade. They are typically used for floors installed Above ground.
What to Look For in an Underlayment for Concrete:
- Moisture resistance or vapor barrier built-in
- Compression strength (especially under furniture or heavy foot traffic)
- Thermal break to reduce the cold from the concrete
- Breathability and airflow to prevent trapped moisture
- Flooring support for: laminate, carpet, engineered wood, etc.
What to Avoid on a Concrete Subfloor:
- Standard foam underlayments that don’t block moisture
- Plywood or OSB without a moisture barrier underneath
- Products not rated for below-grade or slab-on-grade installations
Ideal Underlayment's for Concrete Include:
- Vapor barriers with a dimpled design to provide an air gap.
- Subfloor systems that allow airflow and drainage
- Hybrid underlayments with vapor protection
The Final Word:
The proper underlayment for concrete must do more than cushion. It must protect your flooring from moisture, and provide strong and stable surface for the flooring you choose.