The best flooring for uneven floors due to its attractiveness and durability is epoxy, which can also be designed to mimic a wide variety of appearances.
One of the most common ways to level uneven concrete basements floors is to apply a high quality self-leveling underlayment. To level an uneven concrete floor with a self-leveling underlayment, start by thoroughly cleaning the concrete floor and removing all dust and residue.
For very uneven flooring, laminate sheets or tiles may be a better bet. This material is more flexible, but may reveal the imperfections in the surface. The most durable and attractive option for an uneven floor is often a pour on option, such as epoxy.
Vinyl and Laminate flooring:
Both vinyl and laminate floors are versatile and durable options that can be installed over slightly uneven surfaces. They are relatively inexpensive, easy to clean and maintain, and come in a wide range of patterns and colors so you don't have to sacrifice style for function.
The easiest way is to use a self-leveling compound, also called liquid floor underlayment or floor resurfacer, within sections of level-cut rails. The material flows out like thick syrup, then hardens into a smooth, perfectly level surface, sometimes in less than an hour.
When you're installing a vinyl plank floor or any rigid type of new flooring, it's important for the underlying layer to be both level and flat. If you're installing vinyl planks on top of a concrete floor, the standard tolerance required is for the floor to be level to 3/16” within a 10' radius.
Creating an Even Surface
On the areas with the highest measurements, use a concrete grinder to sand out the bumps, creating a smooth, level concrete floor. In places where the floor dips too low, use a filling agent to create a level surface. Lowes Creative Ideas recommends using a cementitious leveling compound.
Underlayment can help smooth things out, though, but the type you choose will vary depending on your specific reasoning for wanting an even subfloor. That can make choosing the right one for you rather tricky, so here's a quick guide that should lend a helping hand in getting the best underlayment for uneven subfloors.
You can install vinyl on many types of subfloor, including concrete and wood. But that floor must be flat for your installation to be a success. An uneven subfloor can lead to potential problems, such as planks having varying heights that will make the flooring unstable and wear down more quickly.
Uneven floors are rarely caused by problems with the floor itself. The cause is usually settling or shifting of the foundation underneath the floors. If the floor beams and joists are made from wood, like the ones above a crawl space, they will usually bend rather than crack.
Forgetting to level the subfloor
The subfloor must be level before installing laminate flooring. If the subfloor is leveled, the laminate planks will not lay properly, causing uneven and unsightly floors. If the subfloor is not level, you can use a self-leveling compound to level it out.
The most suitable materials for basement flooring are those that are waterproof or moisture-resistant. These include vinyl, engineered wood, rubber, and even carpet as long as it's marine-grade. Tiles made from porcelain or ceramic are also suitable.
All-weather carpet, luxury vinyl flooring and porcelain or ceramic tiles are some of the best flooring options to go over concrete in basements.
Luxury vinyl tiles or planks can also work very well on uneven floors. They are available in the form of tiles or planks that have a click and lock installation method. Like engineered hardwood, it is also a floating floor. Uneven sub-floor prevents vinyl planks to click together.
In short, vinyl flooring itself can be completely self sustainable and does not require an underlayment to function properly. Another reason underlayments may be suggested for vinyl flooring is if the vinyl flooring type is thin. When the vinyl flooring is thin, it becomes a lot easier to flex and bend.
But, just like with any other permanent product, it's imperative that the existing floor is clean and dry, in excellent condition, and most important, level. A flat and level floor is key so that the adjoining vinyl plank flooring don't have varying heights.
If you want to raise the height of a floor, the cheapest and easiest way is to add a thick underlayment designed for the job. There are other options too like adding a framed wooden subfloor or floor leveling compound before installing new flooring.
Fibreboard Underlay
It works to smooth uneven floors, reduces noise, and acts as a thermal barrier. If the subfloor is uneven, fibreboard works to even dips and dents you can't level out. It's also necessary to add a DPM if you're installing fibreboard on top of a concrete subfloor.
Sand Mix, Portland Cement & Gypsum-Based Compound are practical alternatives to the self-leveling compound. These options are cost-effective materials that are ideal for smoothening up your floor. At the same time, you can also try Drywall Compound and Foam.
APPLICATION: Apply CONCRETE LEVELER up to 2" (5.1 cm) thick. For thicknesses greater than 2" (5.1 cm), extend each 50-lb (22.7-kg) bag with 25 lb (11.3 kg) of clean, dry 3/8" (0.95 cm) pea gravel. When extended with aggregate, CONCRETE LEVELER may be placed up to 5" (12.7 cm) thick.
The Causes
A basement floor that is uneven is most commonly caused by soil settlement near the foundation or underneath the footer and slab itself. However, less commonly, a basement slab may be uneven due to conditions present at the initial pour.
Therefore, because concrete is porous, it's a good idea to install a vapor barrier over your concrete subfloor before installing your flooring. This way you can stop the vapor drive of water upward to your floors, protecting them from any damage (source).
As you don't have to install underlay for Vinyl Flooring or LVT, this can go directly onto the concrete subfloor. However, allow 24 hours for your flooring to acclimatise by leaving it out of its packaging. When it's ready, unroll your vinyl flooring and cut to size after measuring your room.