How to Insulate a Concrete Floor Properly Before Making Any Mistake

If you want to do something about your concrete floor, knowing how to insulate a concrete floor properly can really help. You should know that concrete floors are commonly damp and cold.

If you want hardwood flooring on top of your concrete floor, it’s better to insulate it first to prevent heat loss. Insulation can prevent heat transfer between the concrete and your hardwood floor.

Adding insulation can also prevent moisture from entering your wood, ruining and damaging it in the long run. The concrete floor is quite porous, you know?

Can You Insulate an Existing Concrete Floor?

Why not? In fact, the easiest way to do so is to install the insulation right on top of the concrete floor. But let’s not forget about the added extra height. Yes, insulation will affect the floor height quite significantly. So, if you want to insulate your concrete floor, make sure to do it before installing flooring.

how to insulate a concrete floor

There are basically two ways to insulate the concrete floor. First, you use rigid foam insulation to cover the concrete. After that, add plywood (two layers of it) and the finish flooring.

The second method is to attach the wood sleepers right onto your floor. Then, by using rigid foam insulation, fill in the gaps. Afterward, apply the subfloor and add the finish flooring.

What Is the Best Way to Insulate a Solid Concrete Floor?

Not only you need to know how to insulate a concrete floor, but you also need to know the best options for your floors. So, what are they?

  • Radiant Foam Insulation

This insulation is commonly made from extruded polystyrene (XPS) or expanded polystyrene (EPS). This is a popular option for insulating concrete slabs and basement walls. However, although this option is greatly effective for the walls, it’s only performing so-so for the floorboards.

  • Fiberglass Floor Foil

Not only it’s a popular option for different types of homes, but it’s also great for RV implementation. It has impressive thickness, but it doesn’t have enough compressive strength. It means that you should expect somewhat ‘squishy’ subfloor material.

Moreover, such insulation won’t be compatible with electric radiant floor heating, so you may reconsider it.

Read also: Why is Rubber a Good Insulator?

  • Plastic Film Vapor Barrier

This insulation can prevent condensation from happening. It can also prevent risky moisture from developing into mildew or mold. As a moisture barrier, this insulation is impeccable.

But then again, its insulative qualities are quite inferior. It has no R-values, meaning it’s substandard for the concrete floors.

  • Sleepers or Plywood

The sleeper comes as (dimensional) lumber installed on the concrete floor’s top area. The purpose is to provide solid support and ‘nailing spots’ for the hardwood floor (or any other flooring material).

You can use sleeper and plywood to create a durable, tough, and sturdy subfloor structure.

But then again, wood isn’t exactly a great insulation. Sure, it is great when you want to install hardwood flooring, but don’t expect it to provide impressive insulation quality.

  • Rigid Boards

Rigid (foam insulation) boards are basically almost similar to the radiant foam type. But this rigid board has no, whereas radiant foam insulation has a reflective face.

Read also: Attaching the Rigid Foam Insulation Between Studs

If you want to use this board for insulation, choose the one with the proper compressive strength, so it would be suitable for subfloor material. Keep in mind that different brands will have different quality and characteristics.

Moreover, you should also know that most of these foam rigid boards have different thicknesses. They commonly range from one to two inches, affecting the floor height. Let’s not forget that this insulation isn’t the right one for underlayment, especially for (electric) radiant floor heating.

Final Words

Consult the expert if you are considering insulation over your concrete floor. Learning about how to insulate a concrete floor can help you understand your floor better while planning out a better arrangement for flawless finish.

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Insulator is a skilled author and Insulation expert with years of experience in the field. He has authored several articles and books on various aspects of insulation installation, maintenance, and repair.