Most manufacturers recommend that the floor be flat to within 3/16” in a 10 ft. radius. These measurements are consistent with most other types of floor coverings. On floating floors, vertical movement needs to be kept to a minimum.
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.
The best option for slightly uneven subfloors is a direct stick installation (involving nails & glue) if this is a viable option. Floating flooring is not recommended for uneven floors as this increases risk of the planks moving or splitting apart.
Floor Flatness is measured by tracking the difference in elevation between two points 1 foot apart and comparing them with every other 1-foot elevation change across a measured distance or “run.” Floor Levelness on the other hand compares the change in elevation over a distance of 10 feet, by determining the net change ...
Check the Level of the Subfloor
To check for small high or low spots that may not even be visible, place a long level or straight pipe on the subfloor. Move it around to different areas and mark any high or low spots you find with a pencil or marker. Most floors will have at least some slight variations.
Use a self-leveler on low spots on concrete. Self-leveler creates a flat, smooth surface in flooring projects. Self-leveler dries quickly. Pour the self-leveler onto the subfloor, using a trowel to smooth it out.
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.
On average, you are looking at about $3 – $5 per square foot. So, for a 100 square foot slab, it would generally cost between $300 and $500.
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.
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. Not only will epoxy finish out the floor, but it'll also even it out.
For only slightly uneven flooring, sturdy materials such as luxury vinyl plank can also be used for full coverage. The benefit of sturdier types of flooring is that they will give the floor the illusion of being more even than it actually is. For very uneven flooring, laminate sheets or tiles may be a better bet.
The main things that you need to consider when choosing the thickness of your laminate floor are the evenness of your subfloor and any reason you may have to be worrying about noise reduction. If you have a subfloor that is in any way uneven, it pays off to choose a thicker laminate.
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.
Extra Padding Poses a Risk
By adding unnecessary cushioning, you could actually be causing more harm to your floor than good. The added friction could cause the underlayment to wear down quickly and make your floors less stable over time, causing stress on the floating floor's locking system joints.
Self-leveling compound products can be used on concrete floors, wood subfloors that are uneven but still in decent shape, and even over ceramic tile floors—eliminating the task of tearing out the old tiles. Check to ensure that the product you purchase is compatible with your floor.
Self-leveling compound, for example, is an easy way to level and flatten out a vinyl floor before laying laminate planks over the top. Keep in mind, though, that installing new flooring over the old means that you are increasing the overall height of the floor.
Thoroughly vacuum the existing floor, and use a long floor leveler and tape measure to ensure the subfloor is level within 3/16 inch for every 10 feet. You'll need to know how to level a floor: Just sand any high spots and fill the low spots with leveling compound.
No subfloor is perfectly level, but any signs of unevenness and high or low spots must be remedied. Please follow these requirements: Subfloor unevenness cannot be greater than 3/16 of an inch over a 10-foot span or 1/8 inch over a 6-foot span. Subfloors must not slope more than ½ inch per 6 feet (25 mm per 1.8 m)
Ff of 20-30 is a marginal, very obviously bumpy and a poorly finished floor. Ff 30-50 might be considered an “average” industrial floor placed without laser screeds and perhaps typical of work done 20 years ago. Today Ff of 50+ is common with some contactors routinely doing Ff70+ work.