Did you just rip the carpet off and want to put a luxury resilient floor but got stuck? I am pretty sure you are looking at that uneven concrete floor in your basement and confused. What to do and how to fix it so it’s livable?
You have a few options: Grind the floor, use a self-leveling compound, or use a subfloor to get it pretty close to even as possible. I have listed a couple of forgiving flooring materials – carpet and vinyl – to use over uneven concrete floors.
Fixing an uneven floor is just more than leveling. You need more planning that you may expect.
Find and understand all the potential issues that you have on hand. Especially, think through to see why the floor became uneven.
Was it due to a bigger issue that you are trying to solve – or – is it due to a poor workmanship of the builder?
Address the root cause of the issue before fixing the uneven concrete floor in your basement.
Understanding Moisture Issues
If you are up against the uneven concrete floor and thinking how to fix uneven floors in an old house, then this is for you.
One thing that you want to consider before doing any basement project is moisture.
In this case, you are going to put in a floor right on top of the concrete.
As you know concrete is a very porous material and right beneath the concrete is moist dirt that breathes moisture into your basement space.
Now, if you have a perfect concrete this might not be a major issue.
However, since you are here due to imperfect concrete floors, I am pretty sure you have cracks and crevasses.
Now through those cracks, the soil under the concrete is directly exposed leaving vapor in the basement.
You need to fix it.
Refer to other useful articles on moisture related issues and how you can deal with it.
Concrete Preparation Before Fixing
Remember one thing when working on concrete.
Dust is going to be flying all over. So preparing your space is super important. That will save you work down the line.
First off, remove all the furniture and object from your basement space and move it to a closed room where dust would get to.
Remove carpet, rugs, padding and padding strips. If you have old vinyl or any other flooring over uneven concrete, demo and remove all debris.
Use your judgment to see what will be in the way and remove those. All you need is complete access to your concrete floor area.
Remove all debris, dust and loose particles off the floor.
This might mean, booming, vacuuming and cleaning using wet mop too.
Do not start any concrete fixing until you have convenient access and a basement floor that has no debris or dust.
Find all the spots where you find visible cracks and try to seal them with a hydraulic cement. Or a product specific to fix such cracks.
Check this article to see how you can paint over the concrete (if you are planning to not install other flooring products over the concrete, that is)
Uneven Concrete Floor Options and Solutions
You can go one of three possible routes
- Do Nothing (Just fill the cracks and seal the floor)
- Masking with a flooring material and covering it up
- Make it right – Grinding and filling it up
Both from a cost and usage perspective, before spending time and money.
First off you need to identify the high and low spots.
What you do is this.
Get a straight edge. You need at least an 8-foot run.
A 2×4 will work well, but use caution when doing so.
The store-bought 2x4s are not straight. Due to moisture and pressure, they are usually slightly curved. If you want to use those. Use a table saw and cut them straight.
I mean perfectly damn straight. Or you can use a laser leveler if want to be sophisticated.
Then keep the straight edge on the floor. Keep one edge fixed and start rotating the other edge, creating a virtual circle.
Find all the low and high spots as you notice and start making marks.
Leave the Concrete Floor As-is
If the amount and level of imperfection are not noticeable and you are not using the concrete floor in question very much, then you might be fine with leaving it as is.
If it’s just one room that has this issue, then you may consider using that has a storage room.
Think creatively here
Where is the uneven spot in that room? If it is by one corner of the room, you may consider using a furniture to hide it, without doing anything.
If it’s relatively big, and if you think you can use it as a laundry room, then see if the washer dryer and other shelves can cover it up well.
But, what to do when the imperfection is noticeable, big and in a room that you can’t convert to a storage or utility closet?
Never mind. Our next step is to see whether we can mask it, so it’s not noticeable.
In any case, make sure to fill the cracks and at least try to seal it so you don’t have moisture related issues.
As they can affect your indoor comfort and in worst cases can even lead to mold.
Masking Uneven Concrete Floors
I know you want to use that space efficiently. But if you are looking for a temporary solution that is on the easier side, then this might be it.
Carpet and foam
Carpet is soft and a cloth-like material, so contouring around imperfection is a piece of cake.
Check my other in-depth guide on Berber carpet to see if that’s something you like.
Add in a plush foam, which is rubbery and will bridge the gap and even provide the bouncy feel, so no one call feel the imperfection.
This is by far the easiest, quickest and cheapest option to mask the issue. However, you do nothing to fix the problem.
All you are doing is hiding it under the rug. Pun intended 😉
Using a subfloor
Never ignore the moisture barrier. First lay them regardless of what product you use.
If you want to use a product similar to DriCore, then (after the moisture barrier layer) try to get the underlayment set.
Where you have imperfect spots, use shims to level that section before moving on with the installation.
Shims is how you will install a readymade product.
Instead, you can do it yourself using 2x4s.
Since the 2x4s will go on the concrete directly, use a pressure treated lumber in this case.
Find all straight lumber, then lay it on the floor and try to level it. Where you have imperfect spots, use shims.
Fixing It the Right Way – Repair the Flaws
Grinding the high-spots
Have access to a power grinder? Awesome. You don’t have to worry about humps and bumps in your floor.
You can rent one if you don’t have it. They are super important if you have big bumps
If you have a small void on the floor that’s not a big issue because the floor material on top is going to bridge that gap. As long as the gap is small.
But, it’s a pain working with bumps. Even if you have a small bump that is sticking out.
First, you start with the grinding high-spots. Because that will give you a perfect high throughout the room.
Then you can go around with the straight edge and start looking for low spots.
Filling the low-spots
The best way is to use concrete and refinish, but that’s an involved process.
Instead what you do is clean and apply a primer.
The primer is going to help with the adhesion of the new concrete leveling product over an existing concrete pad.
Then use one of the self-leveling concrete products.
Level and mark the area where you want the low spots filled. Then add in self-leveling concrete and spread it over using a straight edge.
Remember to work quickly as it dries out faster and it’s a heavy concrete product. So, you must work all the concrete and remove any excess concrete off the floor.
Leave at least a few days for the flooring fill product to completely cure. Read the manufacturers instruction.
Different products have a different cure time, but it’s always good to leave the floor undisturbed for three days.
Vinyl Plank Flooring on Uneven Concrete
Vinyl planks are awesome. Hands down my latest favorites when it comes to flooring.
In fact, not only on the uneven floor but on any floors.
This is super resilient. Moisture repellent, so mold is not an issue. Doesn’t give, bow or crack. Easy to install and is not expensive. Did I tell you can get any look you want?
What to avoid with vinyl over uneven concrete
Remember to grind down the high spots. They will telegraph through and will be a nightmare after installation.
Sometimes you may not even notice while installing. However, as people start walking you will start seeing the impression coming through.
Secondly, don’t forget to make note of sharp changes in height.
Such as a lump, or room transitions. If you have two different rooms poured concrete at two different height, make note of it.
Now what you can do is to grind the high spots, but also stop the vinyl install near the seams and use a transition strip before continuing the other side.
The transition will not only provide a nice look but also provide an illusion of both being on the same level. That is for a height difference of less than ¼ of an inch.
Vinyl is a super product. It is one of the best flexible floorings for uneven floors.
Well, you have space, but the floor looks horrible. You are confused on how to level uneven concrete floor. I get it.
As a recap this is what you do:
Remember to use the room where you don’t invite guests. Or at least make that an occasional one.
But if you are left with no choice but to host them and use the space actively you have a few different options.
Mask it with carpet or similar product. Grind the high spots and put on a resilient flooring material. Or fill the low spots to make the floor even.
Or use your judgment to use the combination of the individual strategies to see as it fits your situation.
Good luck with the transformation.