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A professional wearing a blue cap and striped shirt uses a spirit level to check the evenness of a newly sanded and refinished wooden floor. The floor appears to be light gray-stained oak wood, showcasing a smooth and modern finish.

How to fix floors that are not level?

Posted on March 26, 2025

Wood Floor Repairs Articles

How to Fix Floors That Are Not Level: A Comprehensive Guide

Ah, the charm of old houses! They come with history, character, and an undeniable warmth that new builds often lack. But with that charm comes a few quirks—like uneven floors. If you’ve ever walked across a room and felt that unmistakable slope beneath your feet, you know the frustrations of dealing with floors that are not level. Whether you’re an avid DIY enthusiast or a homeowner simply trying to maintain the integrity of your home, knowing how to fix unlevel floors is essential.

In this extensive guide, we’ll walk you through the causes of uneven floors, the different methods to rectify the issue, and some tips for preventing future problems. So grab a cup of tea, settle in, and let’s get started!

A professional wearing a blue cap and striped shirt uses a spirit level to check the evenness of a newly sanded and refinished wooden floor. The floor appears to be light gray-stained oak wood, showcasing a smooth and modern finish.

Understanding the Causes of Uneven Floors

Before we dive into the ‘how-tos,’ it’s crucial to understand why your floors might be uneven in the first place. Uneven floors can arise from several issues, including:

1. Foundation Problems

The foundation of your home is crucial for its overall stability. If your foundation is sinking, shifting, or settling due to poor soil compaction or moisture issues, this can lead to uneven floors. In older homes, especially, this is a common problem as the foundation may have settled over time.

A close-up view of a wooden floor frame under construction, featuring light pine wood beams securely fastened with blue metal brackets. The structure is being prepared for flooring installation or refinishing.

2. Moisture Damage

Wooden floors can warp and buckle when exposed to excess moisture. This could stem from a leaky pipe, high humidity, or poor ventilation. When wood absorbs moisture, it expands. If the moisture is not evenly distributed, this can create an uneven surface.

A close-up view of a corner where a light oak laminate floor meets the wall. Visible gaps and unfinished edges suggest the need for sealing or refinishing to improve the flooring's appearance and durability.

3. Improper Installation

If your flooring was not installed correctly, it might lead to uneven surfaces. This can be due to insufficient underlayment or failure to account for the natural movement of the flooring material.

A close-up view of a glossy hardwood floor showing slight gaps between planks, highlighting the need for repair or refinishing. The floor appears to be light ash wood with a polished finish.

4. Natural Settling Over Time

Every home experiences a little settling as it ages. This is a natural process, but it can lead to floors that are not level, especially in older properties.

5. Support Beam Issues

If the support beams or joists beneath your floor are damaged or not properly installed, this can lead to sagging in the floor above. Issues like rotting wood or insect infestations can exacerbate this problem.

A view of a wooden ceiling frame under construction with exposed beams and electrical wiring. The structure uses light pine wood for framing, while the older ceiling features dark-stained wooden planks in need of sanding and refinishing.

Diagnosing the Problem

Before you start fixing your uneven floors, you need to diagnose the problem. Here’s how you can check if your floors are level and understand the severity of the issue.

1. Visual Inspection

Start with a visual inspection. Look for noticeable dips or bumps in your floor. Pay attention to areas where the floor meets the wall; if there are large gaps, this could be a sign of underlying issues.

2. Use a Level

A simple spirit level is one of the best tools for this job. Place it in various locations across your floor. If the bubble in the level is not centred, you’ve got yourself a problem. A laser level can also be helpful for larger spaces.

3. Check Doorways

Do doors open and close without obstruction? If you find that they stick or do not swing freely, this may indicate a problem with floor level.

4. Look for Cracks

Inspect your walls and ceilings for cracks, particularly near door frames and windows. If you notice cracks, this could be indicative of shifting foundations or other structural issues.

5. Consult a Professional

If you’re unsure about your findings, or if the problem appears severe, it’s worth consulting a professional. Structural engineers or building inspectors can provide valuable insight and recommend the best course of action.

The enthusiastic Mr. Sander® team poses together, wearing black and green branded shirts, showing their excitement and professionalism. The team is gathered in front of large windows, sitting on a bench, and cheering. The floor beneath them is a dark, polished hardwood, reflecting their expertise in floor refinishing.

Methods To fix floors that are not level

Once you’ve diagnosed the problem, it’s time to explore your options for fixing those pesky uneven floors. Depending on the severity of the issue and your level of expertise, there are several methods you can employ.

1. Shimming

Shimming is a straightforward and effective solution for minor unevenness in floors. Shims are small, wedge-shaped pieces of wood or plastic that can be inserted under flooring materials to provide support.

How to Shim Your Floors:

  • Identify the low spots: Use a level to determine where the floor dips.
  • Lift the flooring: Depending on your flooring type (carpet, laminate, hardwood), you may need to lift it carefully to access the subfloor.
  • Insert shims: Place the shims under the affected areas, gradually raising the flooring until it’s level. Make sure to keep the shims flush with the subfloor.
  • Secure everything: Once level, re-secure the flooring to prevent movement.
A work-in-progress flooring installation setup, showing plywood boards with blue and red spacers placed in alignment. Tools and equipment, including drills and screws, are visible in the background. The underlying floor appears to be dark-stained hardwood, awaiting refinishing.

2. Self-Leveling Compound

For more significant unevenness, a self-leveling compound might be your best bet. This product is designed to create a smooth, level surface over an existing floor.

How to Use Self-Leveling Compound:

  • Prepare the area: Clean the floor thoroughly and remove any debris. You may need to prime the surface with a suitable primer for better adhesion.
  • Mix the compound: Follow the manufacturer’s instructions to mix the self-leveling compound. Aim for a consistency similar to pancake batter.
  • Pour the compound: Starting at the lowest point, pour the compound and use a squeegee to spread it evenly across the area. The compound will seek its level, so you don’t need to worry too much about precision.
  • Allow to dry: Follow the drying times outlined in the product instructions before walking on the floor again.
A worker uses a yellow spirit level to check the alignment of wide wooden planks during a floor installation project. A miter saw and other tools are visible in the background, suggesting ongoing preparation for sanding and refinishing. The planks appear to be reclaimed oak wood with a rustic finish.

3. Reinforce Joists or Support Beams

If your uneven floors are caused by issues with joists or support beams, you may need to reinforce these structures.

How to Reinforce Joists:

  • Access the crawl space or basement: Ensure you can safely access the area beneath the affected floor.
  • Install blocking: Add blocking between the joists for additional support. This can be done by cutting pieces of wood to fit snugly between the joists and securing them with screws.
  • Use a jack post: If a joist is sagging significantly, consider using a jack post to provide temporary support while you work on repairs.
A view of a wooden ceiling structure undergoing renovation, featuring dark-stained wooden planks supported by light blue beams. A metal jack post is used to stabilize the framework, indicating ongoing repair and restoration work.

4. Replace Damaged Flooring

If your flooring material is warped or damaged, you may need to consider replacing it altogether. This is particularly true for hardwood or laminate flooring that has absorbed moisture.

How to Replace Damaged Flooring:

  • Remove the damaged boards: Carefully lift and remove any warped or damaged planks.
  • Install new planks: Ensure you choose the same material and style to maintain a consistent look. Follow the manufacturer’s instructions for installation.
  • Level the subfloor: Before laying new flooring, check that the subfloor is level, using shims or self-leveling compounds as necessary.
A partially restored wooden floor showing exposed pine floorboards with tools laid out on the surface. A hole in the floor reveals the space beneath the boards, indicating ongoing repair work. Tools like a power saw, hand saw, pliers, and a pen are scattered around the workspace, suggesting a floor replacement and sanding process in progress.

5. Consult a Professional

If you’re facing significant structural issues, or if the problem seems beyond your DIY capabilities, it’s wise to consult a professional. Structural engineers and contractors can provide tailored solutions to restore your floors and ensure your home remains safe and stable.

Mr Sander® team in Westminster, WC1: Our skilled professionals are ready to transform your floors. With years of experience and dedication, we provide top-quality services. Step into our office and witness the excellence that awaits you.

Preventing Future Issues

Once you’ve tackled the immediate problem of uneven floors, you’ll want to take steps to prevent similar issues in the future.

1. Monitor Moisture Levels

Keep an eye on humidity levels within your home. Use a dehumidifier if necessary to maintain a stable environment, especially in basements or areas prone to dampness.

2. Ensure Proper Ventilation

Good ventilation can help prevent moisture accumulation, especially in areas like bathrooms and kitchens. Ensure vents are unobstructed and use exhaust fans where necessary.

3. Regular Maintenance Checks

Periodically inspect your home for signs of foundation problems or water damage. Catching these issues early can save you from more extensive repairs down the line.

4. Invest in Quality Installation

If you plan to lay new flooring, invest in professional installation. Properly installed floors are less likely to suffer from issues of unevenness.

5. Address Repairs Promptly

If you notice any signs of sagging or unevenness, address them quickly. The longer you wait, the more severe the problem may become.

Two images side-by-side showing a worker from Mr. Sander® performing wood floor repairs. In both images, the worker is wearing a bright green shirt with the Mr. Sander® logo on the back. On the left, he is kneeling on a light-coloured wooden floor, inspecting the surface. On the right, he is repairing a dark and worn section of the floor in a different room. Tools and equipment are visible, indicating the ongoing repair process.

Conclusion

Uneven floors can be a nuisance, but with the right knowledge and tools, they’re not insurmountable. Whether you choose to shim, use self-leveling compounds, or consult a professional, you can restore your home’s floors to their rightful level. Remember, understanding the cause of the problem is the first step towards finding an effective solution. With a bit of effort and care, you can maintain the charm and integrity of your home for years to come.

So, roll up your sleeves and get to work—your level floors await!

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