How To Level A Concrete Floor That Slopes

Sep 22, 2021 | Concrete Tips, DIY Tips

Concrete has for a long time been the best material used for making a steady foundation. That’s because it boasts excellent strength and durability. A structure made of concrete has a lifespan of decades, if not its lifetime.

However, concrete is still susceptible to damage. Areas such as the garage, laundry room, basement, and landscape surrounding your home are often prone to imperfections. In short, a concrete surface with high traffic or exposed to chemical damage like salt may eventually crack, sink, heave, and slope.

When you notice a change in gradient in your home, you may wonder how to level a concrete floor that slopes.

The process is pretty easy and includes the following steps:

1. Determine how serious the floor is sloping
2. Measure how much the floor slopes
3. Identify the cause of sloping
4. Inspect the type of material underneath
5. Prepare and clean the current concrete floor
6. Mark off the sloped areas and grind down high points
7. Prepare the bonding agent
8. Prepare the leveling concrete
9. Apply the leveling concrete

Here’s our detailed guide on how to level a concrete floor that slopes:

Determining the Seriousness of a Sloping Floor

Most homebuyers and homeowners tend to ask, how serious is their house’s floor sloping or sagging? To find the answer, you’re looking for. You’ll need to have answers to some of the questions. They include:

1. To what extent is your floor sloped?

Here, you must determine the exact measurement variations of the slope. Is it sloping ¼ inch in 10-ft or 20-ft?

If yes, but you can’t see any other noticeable problems in your home, then it is possible that the sloping isn’t that serious. However, if the sloping is 2-inches in 20-ft, it is a significant concern, and you must investigate it.

2. Are there any indicators that your structure has problems apart from having sloping floors?

A building may have some issues if it has stayed for a long time. Here, you may need to check for possible structural damage warning signs like:

  • Cracked walls and ceilings
  • Cracked base
  • Leaning walls on either the exterior or interior
  • Creaked concrete slab
  • Differential slab or settlement of the structure’s foundation
  • Windows and doors that don’t open or sticks
  • Soil movement problems like soil creep

The magnitude of these structural issues can help you determine the severity of slopping in your home.

3. To what extent does the area in your home slopped?

If so, where exactly? Is it a section that’s sloped, or is it your entire house’s floor?

4. Is the house or property newer or old?

5. Does the sagging problem show signs of stabilizing, or is it worsening over time?

These are some common questions you might want to answer to determine how bad your floor is slopping. Besides, they can help you know the reason(s) for the sloping floor and decide how best to make it right.

Measuring How Much the Floor Slopes

When it comes to determining how sloping your house floor is, guesswork never applies. The only way to tell the seriousness of a sloping floor is to know how much it sags or slopes.

You’ll also need to know the specific place where it slopes (is it in one room, in the hallway, or the entire house?). Plus, determine to what direction the floor is sloping. Here, you may need to try the following ways:

Use a Marble, Golf Ball or Steel Bearing

Home inspectors often use a golf ball or marble to measure how much a floor slopes. And when they suspect that your floor slopes, they’ll place the marble or golf ball on the floor.

Then they watch it as it moves on the floor surface. If the marble or golf ball rolls away, then this means that the floor isn’t level. In most cases, the ball will move much faster if the sloping is greater.

For this method to work, your floor must be uncarpeted or non-ceramic. However, you may not precisely know how great your floor is sloping; For instance, you can’t tell if there’s a 3/8 or 2-inch difference in 10-ft or 20-ft.


This method uses short torpedo levels, which may be 3 foot long levels, 6-foot long levels, etc. These will enable you to determine the presence of a slope on your floor. If you want an extended distance, you can sometimes lay a short level on a long 2 by 4.

The thing is, longer levels work better than shorter ones. A 9-inch short level may not give you an accurate picture of the floor’s levelness like what a 6-foot level does.

Laser Levels

Laser levels tend to project a beam for extended distances. You can buy them on Amazon or at big box stores. They are super easy to use, making it easier to measure your house’s slope. You may also use them to check the drainage slopes in your home, including hanging pictures.

The best part is that these self-leveling levels offer precise measurements than non-self-leveling ones. Unfortunately, it’s tricky to set them up properly. That’s if you want to move the levels around your home to take different measurements.

Phone Level Apps

Measuring the sloppiness of a floor has never been this easy. Thanks to the improved technology, you can download different apps on your phone to help you estimate the level of something.

Some of these apps are accessible online, while others can be purchased. Unfortunately, phone level apps are suitable for use on a small floor area.

Layout Grid

If you want to measure the levelness of an entire house, a layout grid would be more preferable. Here, you can make a floor plan that shows a 5-foot increment. Then, mark and write the height at every point while measuring.

By doing so, you’ll get a clear picture of the areas the floor is sloping. And also by how much. This gives you helpful information that will help you diagnose the severity of a sloping floor.

How to Level a Concrete Floor That Slopes

Now that your floor is sloping, what next? You may want to know how to level a concrete floor that slopes. This section comes in handy to discuss the various steps you can follow to fix the problem.

Identify the Cause

Fixing a sloped concrete floor begins by knowing what caused the issue. By doing so, you can understand how best to repair the concrete. You’ll also determine if the bottom requires you to replace the entire floor or just a section.

If your concrete slab is heaved or sunk, it is critical to address the initial cause of the problem before fixing it. Failure to address the cause will mean that you’ll experience the same issues even after repairing your concrete floor or slab.

Inspect the Material Underneath

When it comes to repairing concrete floors, an inspection of the material underneath is often the first step. Understand what type of material is underneath the foundation or slab to fix your sloped floor.

We often find some void space under a concrete slab caused by a subgrade’s expansion or settlement. A concrete floor made of frost-susceptible material will quickly expand and even shrink over time.

As for clay, it’ll expand during wet conditions and shrink when it dries. Here, you’ll need to get rid of the clay to at least innate elevation and below the freezing point. Also, compact a non-frost-prone subgrade on the top of the floor.

The new concrete floor will boast a robust base to support any amount of load. In short, the capacity of soils to support a concrete slab is a crucial aspect when it comes to the construction of a concrete floor.

If the subgrade below your concrete floor is of suitable bearing capacity, has a solid structure, and needs re-surfacing, you can then pour new concrete over an existing sloped floor. The next step will show you how to do it:

Prepare and Clean the Existing Concrete Floor

When it comes to any DIY project, always make your safety a priority. Put on protective gloves and safety goggles to keep you safe from any tiny materials that may fly out and harm you.

Then begin the process by removing any areas that are loose or damaged. Here, you will need to get your furniture, baseboards, appliances, and other items sitting on or surrounding the sloped floor.

After that, use a special concrete cleaner to give the floor a good and thorough cleaning. This unique tool will help you eliminate any oil, grease, debris, dirt, and stains from the surface.

You can also use a chemical cleaner. Use a scrub brush to remove dirt, oil, or grime residing on the surface. Let the floor concrete slab sit for about half an hour to allow for an excellent adherence with the bonding agent.

A clean floor guarantees you that the new concrete layer will be better and stick to the old one. If the concrete still has imperfections, such as flaking or chipped areas, a metal scraper will help you eliminate such flaws.

Finally, vacuum the whole area and wash it using a pressure washer. Rinse the concrete properly to remove the cleaner residue.

Mark Off Slopped Areas and Grind Down High Points

The next thing to do is to spot and mark off the plopping areas. To do so, place a leveling bar along the floor. Move a concrete grinder back and forth over the floor to shave down the highly elevated sections until the spots are level with the entire floor.

Once you finish this process, you can vacuum the floor to remove any remaining debris and dust. Alternatively, you can place a few marbles on the floor and let them roll away.

If you notice them moving on one side, then the floor is uneven. And if they stop on some areas, then the floor has dips. Make sure you mark these areas and grind them down to level.

Prepare your Bonding Agent

After your concrete floor is clean and dry, the next step is to prepare a bonding agent. Follow the package instructions to prepare the bonding agent correctly. You can install a mechanical bonding agent like steel fitted into epoxy to bond the two layers of concrete together.

Prepare the Leveling Concrete

Combine your concrete compound with water in the correct ratio. Then use a mixing drill to combine the two until you get dense and effortless concrete to pour. However, the agents you use and the thickness of the concrete may adjust depending on:

  • Application of the concrete slab
  • Floor surface you’re working on
  • Steps and procedures you follow
  • Chemical slabs you use in the process

Apply the Leveling Concrete

Start by covering any drains on the floor. Then, pour the concrete using a nap roller. Use a squeegee to spread it evenly to all edges and corners of your room. Make sure you use a leveling bar to level the concrete over the surface as you go.

The concrete will take about 20 minutes to start drying. So, it is advisable to apply it as fast as possible to give your new concrete slab ample time to dry out. But, the drying time may vary depending on the brand or manufacturer of the concrete.

Usually, the average drying time is about 48 hours, after which you can get your furniture and belongings back onto the floor. The whole process from the beginning to the end can last for about two days.

Sloping Floor Verses Sagging Floors

In different buildings, homes, and even companies, the floor is never leveled perfectly as desired. You may notice the floor sloping or sagging as you move around.

But, what is the difference between these floors? This section will look at the common differences between sloping floors versus sagging floors.

Sloping and sagging are pretty related to one another. A sagging floor contains a slope in each of the sides of the sag. Sagging often occurs due to poor framing or overweight of the floor.

Sloping floors, on the other hand, may also be due to framing problems. However, it is barely caused by issues related to foundation and even soil used when building.

Both sloping and sagging floors should be looked into to avoid trouble in the future. This may include damage to the floor and even much more.

Almost every home has concrete floors which are not excellently level. As such, most homeowners are unhappy living on such foundations. At times, it is advisable to check how level your floors are and inspect for any structural issues.

Always start by understanding the seriousness of the sagging or sloping floor. Then use suitable methods to measure how much your concrete floor is sloping. Once you notice unevenness, you may need to start the leveling process.

Let Us Help You get your Feet on Solid Ground

Nashville Concrete Contractors make the concrete construction process easier. From the first contact to contract, we are Nashville’s go-to concrete company; specializing in driveway and patio installation and repair, as well as decorative and stamped concrete design. Contact the NCC team today at 615-505-3595 to have our experienced concrete division assist you with your next concrete-related project.