Your Guide to Basement Subfloor Options

You may not think much about your basement beyond just seeing it as a place to store stuff. Often, basements are left to the kingdom of cobwebs, darkness, and grandpa’s old baseball card collection. But your basement also needs care and attention if it is to last a long time. A basement is an important structural element in a lot of homes, and it’s also a part of the house that is exposed to a lot of different forces such as moisture, temperature changes, and shifting ground.

For this reason, it’s important to put time and effort into designing your basement so that it is the best it can be, and a huge part of that means getting a good subfloor installed. A basement with a decent subfloor will better stand up to floods and will be able to weather all challenges nature throws its way all while keeping your stuff safe.

What is Basement Subfloor?  

Before you can put down some flooring to spruce up your basement, you’ll need to install a subfloor. This basement subfloor will sit above the bottom-most floor (typically concrete). The point of the subfloor is to increase insulation and act as a buffer against moisture invading your basement. Because a basement is dug into the ground and lined with concrete, it’s only a matter of time before ground moisture starts making its way in. A high 8-foot ceiling would help keep your basement dry, but most basements are not taller than 7 feet. 

Avoid Moisture in Your Basement

As such, the basement subfloor is an absolute must-have if you plan to install some nice flooring material such as carpeting or laminate in your basement. So if your goal is to transform your basement from a dingy storage space into a liveable everyday room in your house, you’ll need to add a subfloor. As such a subfloor isn’t necessary for every basement, especially if you don’t want to convert your basement into usable space. But if you choose to do so, basement subflooring will play a big role in keeping a basement warm, dry, and cozy.

There’s another compelling reason to install a subfloor beyond just wanting to turn your basement into the ultimate rumpus room. Excessive moisture can cause or contribute to structural problems, and since most homes have their foundations in the basement that could be a real problem. A good basement subfloor will work wonders in keeping your foundation in good shape and will help your home’s structure stand the test of time.

Basement Durability Is of Utmost Importance for the Long Run

Your Top Basement Subfloor Options

Oriented Strand Board (OSB)

OSB is so named because it is made up of a bunch of strands of 4-inch wood that are layered in an interlaced crossing pattern. OSB is typically glued and pressed together making for a very dense wood surface that is much more absorbent than regular plywood. This is good news because it means that OSB can handle a lot more moisture than a regular plywood subfloor.

OSB Stands Against Moisture Much More Than Plywood Usually Does

OSB is installed the same way as a plywood basement subfloor using glue or nails to secure the subfloor to your basement’s floor joists, so installation is a cinch. However, OSB usually needs some extra layering to add stability to the subfloor. This limits the options you have for flooring that can go over your subfloor. Ideally, you want to use bamboo or some other wood flooring material since this will strengthen the basement floor’s structure.

You might also have to add a plywood underlayment (under the subfloor) to further increase your subfloor’s strength. Products such as DRIcore Subfloor are OSB sandwiched with a moisture barrier and offer a shortcut so you don’t have to go through the trouble of adding an underlayment yourself.

The More Secure Your Subfloor Against Moisture, the Better

Concrete Slab

Believe it or not, a concrete basement subfloor can also be effective at solving your basement moisture woes. Once it’s dry, a concrete subfloor does a good job at absorbing moisture and can be a solid, durable, and dependable subfloor for years to come. It works especially well if you’re planning to add tile or natural stone flooring to your basement. Concrete subfloors are especially good for hotter parts of the country since the cold subfloor will help keep things nice and cool.

There are some things to consider though if you want to get a concrete subfloor. For one, concrete is made using water and needs to be left to dry before it can be used as a subfloor. This can take a while and once the concrete is dry you’ll still have to add some plastic underlayment to act as a moisture barrier since concrete is not completely immune to water. Also, because it’s cool, concrete won’t be a good choice if you have cold winters. You should avoid using a concrete subfloor if you want to add hardwood flooring.

Prioritize Insulating and Waterproofing Your Basement

Plywood

When it comes to basement subfloors this is the most common option. It was the only option available to most homeowners until the 1980s, so it’s no surprise that it can be found in most basements today. Plywood has some simple yet huge benefits that make it an excellent choice as a subfloor. Because it is made with sheets of wood that have been glued and pressed together, it’s quite dense and solid.

As such it doesn’t contract or expand as much as regular wood does when exposed to moisture or fluctuating temperatures. It is also able to absorb more moisture than solid wood. Plywood subfloor is installed using the tongue and groove method, and this makes it the perfect base for almost any flooring material. A plywood subfloor can support hardwood,  bamboo, and laminate alike. For more flexible flooring materials such as laminate or carpeting, half-inch plywood subfloors should do just fine, but you’ll want something thicker for nail-down hardwood or floor tiles.

The only real disadvantage with plywood is that it can move around and squeak when walked over, but this is easily fixed by applying glue to your basement’s floor joists.

Plywood Is Simple and Popular for Basement Subflooring

High-Performance Panels (HPP)

This is the next level above plywood and OSB basement subfloors. High-performance panels have many of the same advantages as these two materials but minus the disadvantages. They are specifically designed to be moisture resistant and have a moisture-proof resin injected into them.

Unlike plywood or OSB, high-performance panels are much less prone to swelling, warping, delaminating, or cupping due to moisture. This allows for basement subfloors to last longer and reduces the amount of maintenance needed. HPP is both stiffer and more durable than OSB and plywood, making it easier to install and easier to keep in good shape. It costs a bit more than more basic alternatives, but if you gotta have the most durable type of subfloor out there, HPPs are a sure bet.

HPP Is Among the Most Durable Options You Can Get for Basement Subflooring

Wood Plank Subfloor 

Many mid-century homes used wood plank subflooring before the advent of plywood and other materials. While wood plank can be relatively sturdy, it does come with its issues as any homeowner who has wood plank subflooring will know. These planks, usually made of pine, fir, or other softwood become loose with time, leading to squeaky and uneven floors. If you happen to have a wood plank subfloor, fret not for there is a way to fix it up nice.

A wood plank subfloor can be leveled and strengthened in two ways. The first way is to cover it with particleboard. This will help bridge the gap between uneven planks and is a good solution if you want to put down carpeting. Alternatively, installing a hardboard underlayment will achieve the same effect, although it will require a bit more work.

Wood Planks Can Be a Good Alternative for Basement Subflooring