How Much Will You Spend Replacing Your Subfloor?

Planning a home renovation in today's economy is tough enough. When it comes to flooring, if you need a new subfloor, there are multiple costs to consider. The basic average range is between $428 and $2,978 (via HomeAdviser) for a room measuring approximately 300 square feet. But there's a lot more to consider, which we'll be discussing. If you're wondering whether you really need one, there are a few telltale signs to look for. Most of the time, the subfloor will last for the life of the home, but sometimes it can become damaged.

One sign is if you have sinking sections of floorboards, this typically indicates moisture has caused extensive damage to your subfloor. Another big sign is tiles that begin to crack and pop out of place. In this case, it's possible that the proper underlayment was not used on top of the subfloor. Cupping floorboards is another possible sign of damage underneath. You won't want to put new flooring on top of a defective subfloor, so let's break down some of the costs involved.

Depending on the material you choose for your subfloor, per square foot prices typically range from $3 to $10, per Angi. However, this is just for materials and doesn't include labor. Labor costs will add $25 to $35 per hour to your end game, but unless you have some decent experience, it's not advised as a DIY project. The material you use for the subfloor is the biggest consideration. The most common type is plywood is ⅝ inch thick panels that are going to run between $2.50 and $3.50 per square foot, and of course the thicker you go, the higher the cost.

In basements or bathrooms, you may want to opt for moisture-proof engineered panels called Amdry panels, for about $3 per square foot. You'll also need connectors for these at $20 for a 15-pack. OSB is cheaper than plywood, but can't be used for ceramic tile or stone, and it's weaker than plywood. Concrete will run about $6 per square foot. Additionally, if you're putting in radiant heating, a Warmboard subfloor will be required, costing you about $7 per square foot.

There are a few other costs to take into consideration when replacing a subfloor. For example, you will need to have the joists inspected and may have to replace one or more, depending on the extent of the subfloor damage. According to HomeAdviser, joists can cost between $100 and $2,000 each. All subfloors should have an underlayment, as well, which may or may not have to be replaced. If you're installing a different type of flooring, it may require a special underlayment, or the one you had may have become damaged.

Another factor is of course the top layer of your flooring. If you weren't planning on replacing it anyway, then this is going to be another cost. Count on anywhere from $4.50 to $30 per square foot for installation of new flooring, per Bob Vila. Carpet represents the least expensive, while tile and stone options are on the high end. Just keep in mind all of these things that can affect the total investment when replacing your subfloor.