Leveling Basement Floor Joists How-To (2 Hour Fix!)

Let’s talk about something that’s foundational (literally!) to the health of your house: your basement floor joists.

A level and stable foundation is the unsung hero of any home. It’s what keeps everything else aligned and prevents a whole host of problems down the road.

Basement floor joists are absolutely crucial. They’re the backbone that supports the weight of everything above – your floors, walls, furniture, and even you!

Addressing issues with these joists isn’t just about fixing a squeaky floor; it’s about ensuring the long-term structural integrity of your home and boosting its value.

I’ve seen firsthand how neglected joists can lead to major headaches, and I’m here to tell you that you don’t have to let that happen.

In this article, I’m going to walk you through a straightforward, step-by-step guide on how to level your basement floor joists yourself.

And the best part? You can likely tackle this project in about two hours!

Whether you’re a seasoned DIY enthusiast or just starting out, I’m confident that this guide will empower you to take control of your home’s foundation.

So, grab your tools, and let’s get started!

Section 1: Understanding Basement Floor Joists

Okay, let’s dive into the nitty-gritty of basement floor joists. What exactly are they, and why are they so important?

Simply put, floor joists are horizontal structural members that span the distance between foundation walls or support beams.

Their primary purpose is to support the weight of the flooring, walls, and everything else above.

Think of them as the “bones” of your floor system.

You’ll typically find floor joists made from wood. That includes solid lumber or engineered wood products like laminated veneer lumber (LVL) or I-joists.

Each material has its pros and cons in terms of strength, cost, and resistance to moisture.

Now, why is proper leveling so critical? Well, uneven or sloping joists can trigger a domino effect of problems.

I’m talking structural damage, uneven floors (which can lead to tripping hazards and furniture wobbles), and even increased risk of pests and mold due to moisture accumulation in low spots.

According to the American Society of Civil Engineers, unaddressed structural issues can reduce a home’s value by up to 20%! [^1^]

So, how do you know if your basement floor joists need some TLC? Here are a few telltale signs I’ve encountered over the years:

• Bowed floors: This is a pretty obvious one. If your floor visibly sags or dips, it’s a good indication that the joists underneath are out of whack.

• Cracks in the walls: Uneven settling caused by unlevel joists can put stress on your walls, leading to cracks, especially around doors and windows.

• Doors that stick: If you’re constantly fighting with doors that won’t open or close properly, it could be a sign that your floor joists are causing the door frame to shift.

• Squeaky floors: While squeaks can be caused by other factors, they can also indicate that the floorboards are rubbing against unlevel joists.

• Visible sagging or warping of the joists: Take a close look at the joists themselves. If you see any obvious signs of sagging, warping, or rot, it’s time to take action.

If you’re noticing any of these symptoms, don’t panic! It doesn’t necessarily mean your house is about to collapse. But it does mean it’s time to investigate and take steps to correct the problem.

Section 2: Tools and Materials Needed

Alright, let’s get down to brass tacks. To tackle this leveling project, you’ll need to gather the right tools and materials.

Here’s a comprehensive list of what I recommend having on hand:

Tools:

• Leveling jacks or shims: These are your primary weapons for lifting and supporting the joists. You can find adjustable leveling jacks at most home improvement stores. Shims, which are thin, tapered pieces of wood or metal, are great for fine-tuning the level.

• Carpenter’s level: This is essential for determining how far out of level your joists are and for ensuring that you’re making accurate adjustments. I prefer a 4-foot level for this task.

• Measuring tape: You’ll need this to measure the span between joists and to determine the height of shims or jacks needed.

• Hammer and nails: For securing shims and wood blocking (more on that later).

• Saw: If you’re using wood shims, you might need a saw to cut them to the appropriate size. A hand saw or circular saw will do the trick.

• Safety gear: This is non-negotiable! Always wear safety glasses to protect your eyes from debris and gloves to protect your hands.

Materials:

• Shims (wood or metal): As mentioned earlier, these are crucial for fine-tuning the level of the joists. I recommend having a variety of thicknesses on hand.

• Wood blocking: This is used to provide additional support to the joists, especially if you’re raising them significantly.

• Fasteners (screws, nails): To secure the shims and wood blocking in place. I prefer using screws for added holding power.

Now, I can’t stress enough the importance of using quality materials. Don’t skimp on the cheap stuff!

Your floor joists are a critical part of your home’s structure, and you want to make sure your fix is long-lasting.

Invest in pressure-treated lumber for wood blocking, as it’s more resistant to moisture and rot.

And when it comes to shims, I recommend using hardwood shims, as they’re less likely to compress over time.

I’ve seen many homeowners making this mistake, and they end up with the same problem after a few months.

Section 3: Preparing for the Job

Before you start swinging that hammer, let’s talk about preparation. Taking the time to properly prepare your workspace will make the leveling process much smoother and safer.

First things first: clear the workspace. Remove any debris, furniture, or obstacles from the basement that might get in your way.

Give yourself plenty of room to move around and access the joists.

Next, inspect the joists for signs of damage or rot. Before you start leveling, you need to make sure the joists are structurally sound.

Look for any soft spots, cracks, or signs of insect infestation. If you find any significant damage, you may need to replace the affected joists before leveling.

I always recommend consulting with a qualified contractor if you’re unsure about the extent of the damage.

While you’re down there, take a look at the overall condition of the foundation walls and surrounding areas.

Are there any signs of water damage or cracks in the foundation? Addressing these issues before leveling the joists can prevent future problems.

Now, let’s talk safety. Basements can be damp and poorly ventilated, so it’s important to take precautions.

Make sure you have proper ventilation in the basement by opening windows or using a fan.

And as I mentioned earlier, always wear safety glasses and gloves to protect yourself from debris and splinters.

If you’re working with power tools, make sure you’re familiar with their operation and safety features.

I always unplug power tools when I’m not using them to prevent accidental starts.

A little bit of preparation goes a long way in ensuring a safe and successful leveling project.

Section 4: Step-by-Step Guide to Leveling Basement Floor Joists

Alright, here’s the moment you’ve been waiting for: the step-by-step guide to leveling your basement floor joists.

Follow these instructions carefully, and you’ll be well on your way to a level and stable foundation.

Step 1: Assessing the Current Level

The first step is to determine which joists are out of alignment. Grab your carpenter’s level and place it perpendicular to the joists, spanning across several of them.

Observe the bubble in the level. If it’s centered, the joists are level. If it’s off-center, the joists are out of alignment.

Repeat this process at several points along the length of the joists to get an accurate assessment of the overall level.

Step 2: Identifying Low Spots

Once you’ve identified the joists that are out of level, it’s time to pinpoint the low spots where adjustments are needed.

Use your measuring tape to measure the distance between the bottom of the joist and the floor or support beam below.

Compare these measurements across multiple joists. The joists with the largest gaps are the ones that need to be raised.

Mark the low spots with a pencil or marker so you can easily identify them later.

Step 3: Installing Leveling Jacks or Shims

Now comes the fun part: installing the leveling jacks or shims. If you’re using leveling jacks, position them underneath the low spots you identified earlier.

Make sure the base of the jack is resting on a solid, stable surface. Slowly raise the jack until it makes contact with the bottom of the joist.

If you’re using shims, start by inserting them into the gaps between the joist and the floor or support beam.

You may need to use a hammer to gently tap the shims into place. Start with thin shims and gradually add thicker ones until the joist is level.

Important Note: When raising the joists, do it slowly and carefully. Avoid raising them too much at once, as this can put undue stress on the surrounding structure.

I usually recommend raising the joists no more than 1/4 inch at a time.

Step 4: Adjusting the Level

After you’ve installed the leveling jacks or shims, it’s time to fine-tune the level. Place your carpenter’s level back on top of the joists and observe the bubble.

If the bubble is still off-center, make incremental adjustments to the jacks or shims until the joists are perfectly level.

This may require some trial and error, but be patient and keep making small adjustments until you achieve the desired result.

Step 5: Securing the Joists

Once you’re satisfied with the level of the joists, it’s time to secure them in their new position.

If you’re using leveling jacks, tighten the locking mechanism to prevent the jack from slipping.

If you’re using shims, secure them in place with nails or screws. Drive the fasteners through the shims and into the joist and the floor or support beam below.

For added stability, you can also install wood blocking between the joists. Cut the wood blocking to the appropriate size and nail or screw it into place.

Step 6: Final Inspection

After you’ve secured the joists, it’s time for a final inspection. Double-check the level with your carpenter’s level and make any necessary final adjustments.

Also, inspect the surrounding area for any signs of stress or damage.

If you notice any cracks in the walls or ceilings, it could be a sign that you’ve raised the joists too much.

In that case, you may need to lower the joists slightly and add additional support.

And there you have it! You’ve successfully leveled your basement floor joists. Now, let’s talk about what to do after the repair.

Section 5: Post-Repair Actions

Congratulations! You’ve leveled your basement floor joists. But the job isn’t quite done yet. Here are a few post-repair actions to ensure a long-lasting fix:

First, replace any flooring that may have been affected during the process. If you had to remove any floorboards to access the joists, make sure you replace them securely.

Use the appropriate fasteners and adhesives to ensure a tight and seamless fit.

Next, inspect the basement for any other potential issues that need to be addressed.

Now that you’ve leveled the joists, you may notice other problems that were previously hidden, such as water leaks or mold growth.

Addressing these issues promptly can prevent further damage and maintain the health of your home.

Here are a few tips for maintaining your newly leveled joists over time:

• Keep the basement dry: Moisture is the enemy of wood. Make sure your basement is properly ventilated and that any water leaks are repaired promptly.

• Inspect the joists regularly: Take a walk around your basement every few months and inspect the joists for any signs of damage or movement.

• Address any issues promptly: If you notice any problems, don’t wait to address them. The sooner you take action, the less likely the problem is to escalate.

I recommend routine checks at least twice a year to catch any future issues early.

Conclusion

So, there you have it! Leveling your basement floor joists is a proactive measure that can significantly impact the long-term health and stability of your home.

It’s not just about fixing a squeaky floor; it’s about protecting your investment and ensuring the safety of your family.

And the best part? You can do it yourself in just a couple of hours! With the right tools, materials, and steps, homeowners can successfully tackle this issue.

I’ve seen firsthand the satisfaction and empowerment that comes from completing this job yourself.

It’s a great feeling to know that you’ve taken control of your home’s foundation and made a lasting impact on its safety and stability.

So, go ahead, grab your tools, and get to work! You’ll be amazed at what you can accomplish. [^1^]: American Society of Civil Engineers, “Report Card for America’s Infrastructure,” 2021.

Learn more