Subfloor Requirements
For Hardwood Flooring Installation

One of the most important parts of your hardwood flooring installation is the part that’ll never be seen – your subfloor.

The subfloor is what lies beneath the planks of solid or engineered hardwood flooring. It’s the foundation that provides a solid place for your hardwood to sit for years to come. Because so much is resting on the strength of your subfloor, it is critical that you ensure all the subfloor requirements are met before you install.

Here are some factors to consider as you determine whether your subfloor is up to the task of protecting and supporting your new hardwood floors.

Types of Installation

The first thing to consider is the type of installation. Stapling or nailing your flooring to the subfloor is the most common way to install solid hardwood. With engineered floors, you can also opt for glue-down or floating installations. Subfloors, such as vinyl, carpet, concrete, or ceramics cannot support a solid hardwood installation and should be removed before you install. An engineered hardwood can be installed over a concrete, wood, tile and full adhered vinyl subfloors when installed as a floating or glue-down floor.

Be sure to read the manufacturer requirements of your subfloor before you begin installation.

Flooring Grade

The grade of your flooring matters too. The flooring grade is based on the ground outside. For example, basements are almost always below grade, since they are below ground level.

Solid hardwood floors should not be installed below grade, or below the ground outside. This makes it difficult (if not impossible) for moisture to escape. Instead, you should consider engineered hardwood floors if you want to install below grade. These floors look similar (if not identical) to hardwood floors, but they offer better protection in below-grade environments.

If you’re installing your floors above grade, you must consider the strength of the structure where you’re doing the installation. Is the subfloor rigid or strong enough to support your hardwood flooring? A wood subfloor should be OSB or plywood of 3/4″ or thicker for a hardwood floor installation. Particle board and chipboard are unacceptable for solid hardwood installations, but may be used in an engineered flooring install.

Moisture Levels

The room where you plan to install your floors matters quite a bit too. If you plan to install your flooring in a bathroom, kitchen, or mudroom, make sure you have enough ventilation to keep your subfloor just as dry as the top surface of your flooring.

Moisture is damaging for solid and engineered hardwood floors. No matter where the moisture hits the floor, it can ruin the integrity of your installation. Make sure the subfloor is sealed from cracks and doesn’t have any uneven areas where water could pool below the surface.

Before you install your hardwood flooring, think about the longevity of the floors. To keep them lasting for generations to come, you must start by meeting all of the subfloor requirements.

Click to learn more about how to prepare your wood subfloor or your cement subfloor.

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