Can I Lay Hardie Board Over Concrete?

Hardie Board

• Hardie board is actually a type of cement fiber board. This is a type of durable construction board that is made from core materials covered with a layer of cement mortar. Many boards use fiberglass mesh or a similar material for the core, but Hardie board materials do not use any type of glass mesh. It is sturdy, very water-resistant, and has heat-resistant properties. However, it is designed to be installed over plywood, not concrete.

Problems

• It can be difficult to find a good subfloor material to lay over concrete. Hardie board has its advantages, but the cement fiber boards cannot easily form strong adhesive bonds with concrete. Moisture can also be an issue, since the porous concrete floor can allow moisture to pass through, trapping it under the Hardie board and causing long-term problems.

Other Hardie Materials

• There are a number of other Hardie construction materials, but switching to a different problem will not solve your concrete issue. Neither 1/4 inch nor Hardiebacker 500 is designed for use on concrete. The other products are not designed to be subfloors at all. Hardiewrap can help seal the outer walls of a basement to manage moisture problems, but you will need to find a new solution for your concrete preparation.

Alternatives

• If you have a concrete leveling issue, you can use an epoxy leveling compound to fill in depressions in the surface to prepare it for flooring. Look for a flooring you can install directly over concrete, like certain types of vinyl or manufactured wood. You may also be able to find a floating subfloor designed to be used over concrete surfaces.