How to Level a Floor

How to Level a Floor

Achieving a level floor is a fundamental aspect of any renovation or construction project. It sets the stage for a professional finish and ensures the longevity of your flooring. So, it is good to know how to level a floor.

In this guide, we cover all the critical factors to consider and the processes involved in successfully leveling a floor. You’ll gain a high-level overview of variables such as floor materials, construction methods, and the extent of unevenness – all of which impact the optimal approach.

Armed with this practical knowledge, you can decide on the best way to finally achieve that smooth, level surface you’ve been dreaming of. Say goodbye to the frustrations of uneven floors and embrace a seamless, safe living environment.

How to Level a Floor

Source: / Photo Contributor: Olha Nosova

How to Level a Floor

To level a floor, you should start by identifying uneven areas. Use self-leveling compounds or shims to fill in low spots. For wooden floors, consider adding plywood to achieve an even surface. 

Additionally, we advise you to always prioritize safety by following guidelines and using appropriate tools. If uncertain, seek advice from a professional. After leveling, allow ample drying before applying any flooring material.

How to check if floor is level

You have a few options to check if a floor is level. One is using a spirit level or a straightedge. With a spirit level, you place it at different spots on the floor, making sure the bubble falls within the marked lines. 

Another method is to lay a straightedge across the floor and look for any spaces between it and the floor. These methods offer straightforward ways to assess floor levelness without requiring special tools.

What Causes an Uneven Floor?

An uneven floor can have multiple causes, such as foundation settling, water damage, and general wear and tear. Over time, as homes age, the soil underneath can shift unevenly, causing the foundation to settle. This settling results in dips, slopes, and humps in the floors above.

Exposure to moisture can cause wooden floor components like joists and subfloors to swell, warp, or rot. This leads to raised areas or depressions becoming noticeable. Even high-traffic areas can wear down over decades, concentrating this wear into visible dips or depressions.

Before leveling the floor, it’s crucial to identify the specific type of unevenness present – whether it’s dips, humps, or slopes spread across a larger area. This identification helps determine the appropriate leveling techniques and materials needed to achieve effective and long-lasting results.

How to Prepare for Floor Leveling

Cleaning and removing old flooring

You should start by thoroughly cleaning the existing floor surface. Remove any dirt, dust, or debris. This step ensures the leveling compound adheres properly. 

If the floor has old vinyl, carpet, or laminate installed, carefully remove these first using a pull bar or knee kicker to avoid damaging the subfloor underneath. Also, excess moisture can cause leveling compounds to fail. 

Cleaning and removing old flooring

Source: / Photo Contributor: Zoran Photographer

Addressing moisture issues

To ensure proper preparation, you need to start by using a moisture meter to check the levels in the subfloor. If there’s a concrete slab, check that, too. The moisture levels must be below 12% for wood subfloors and 3 lbs per 1000 sq. ft for concrete. 

If you find high moisture levels, it’s crucial to take action immediately. We advise you to Identify and eliminate the source of moisture. Installing a vapor barrier or using a dehumidifier might be necessary as a first step. 

Also, take the time to clean and remove any old flooring. Addressing these moisture issues will create an ideal surface for the leveling product to adhere to properly and cure over the long term.

Leveling Methods for Various Floor Types

To level your floor effectively, start by assessing your floor type. If it’s concrete and has low spots, opt for self-leveling compounds. Simply mix the compound, pour it onto the low areas, spread it evenly with a trowel or squeegee, and let it cure.

For uneven wooden subfloors, plywood sheets and shims are your go-to solution. So, you need to identify the high and low spots, cut plywood to fit the low sections, shim them to level, and secure them to the subfloor joists.

When dealing with isolated high spots on concrete, grinding becomes necessary. We suggest you utilize an angle grinder with a concrete turbo cup wheel. Grind down the peaks until they’re level with the surrounding surface. 

Moreover, ensure any dust is thoroughly cleaned up. If needed, patch the ground area with a self-leveling compound.

Remember, safety is paramount. Always wear appropriate gear, including eye, breathing, and hearing protection, especially when grinding concrete.

Dealing With Major Unevenness

Minor dips and slopes can usually be smoothed out using methods such as self-leveling compounds or plywood shims. However, extra caution is necessary when dealing with significant unevenness across large areas. 

If the floor is more than 1 inch uneven over just a few feet, we advise you to seek professional advice. In such cases, consulting a structural engineer or a foundation repair specialist would be prudent.

They can also assess whether bigger structural issues, like foundation settling, are causing the problem. Extensive major sloping might indicate significant underlying issues that simple leveling won’t solve permanently.

Furthermore, issues such as soil compaction, plumbing leaks, foundation cracks, bouncy floors, or sticking doors and windows could be present. Hence, a professional inspection can pinpoint the root cause. Sometimes, structural repairs may be necessary first.

These repairs could involve underpinning, foundation piering, or slab jacking. These methods stabilize the home before leveling the floors, ensuring long-lasting results. Attempting major leveling without addressing underlying structural defects can lead to future unevenness.

Installing a New Floor Covering Over a Leveled Floor

Allowing proper curing time

After successfully leveling your floor, it’s important to allow the leveling compound ample time to fully cure and dry. This step is crucial before installing new flooring. Depending on the manufacturer’s specifications, it typically takes 12-72 hours.

But we suggest you first use a moisture meter to verify acceptable moisture levels. The ideal preparation and installation approach depends on the type of new floor covering you’ve chosen. 

Choosing the right underlayment

You should opt for a calcium aluminate or polymer-modified cement-based self-leveling underlayment for rigid surfaces such as tile, vinyl plank, or hardwood. This choice ensures a flat, smooth foundation for your new flooring. 

If you’re installing flexible sheet vinyl or carpet, a more cost-effective gypsum-based compound may be suitable. However, on wood subfloors, you might need an additional moisture barrier. 

Always consult the flooring manufacturer’s guidelines for the best installation practices. With careful preparation and adherence to these instructions, your newly leveled floor will be a durable and aesthetically pleasing base for your new floors.

Choosing the right underlayment

Source: / Photo Contributor: Arturs Budkevics

Maintenance and Care

Once your floors have been skillfully leveled, it’s important to maintain them to ensure their longevity. Regularly check your floors, especially in high-traffic zones, for any signs of unevenness, such as dips or raised areas. Catching these issues early allows for targeted re-leveling, preventing them from worsening over time.

Moisture is another factor that can affect the level of your floors. Keep an eye out for leaks from various sources like pipes, windows, appliances, or the exterior of your home. 

Excess moisture can cause leveling compounds to weaken or separate from the subfloor. So, you need to address any leaks promptly and consider using dehumidifiers in areas prone to dampness, like basements.

By staying vigilant and addressing unevenness and moisture promptly, you can avoid the need for extensive re-leveling in the future. With regular inspections and proactive maintenance, your floors will maintain their smooth, even surface for years to come.


Achieving a level floor is essential for any construction or renovation project, ensuring a professional finish and long-term durability. We offered practical solutions for dealing with uneven floors caused by wobbly furniture and potential hazards. 

We also covered all critical factors, from assessing floor materials and construction methods to tackling specific types of unevenness. Now, you can confidently choose the best approach to achieving a smooth, level surface. 

Say goodbye to floor frustrations and embrace a seamless, safe living environment! 

Mark is a seasoned home services contractor and now serves as the Director of Market Research for Services Curated.