How Uneven Can a Floor Be for Laminate? (Complete Guide)

Laminate flooring can not be installed over an uneven floor. This issue raises a very important aspect of how uneven a floor can be for laminate that is unsuitable or needs fixing before installing laminate flooring over it.

Knowing this probably you would also want to know the answer if you have an uneven floor and you want to install laminate flooring. 

So, to help you out with installing laminate flooring over an uneven floor, this article is going to answer this question with facts and explanation. 

How Uneven Can A Floor Be For Laminate?

A floor that has deep plunges and bumps which have a depth of more than 3/16 inch in any direction is considered as uneven floor. And laminate flooring can’t be installed over such a floor because the level of tolerance of laminate flooring on a floor is 3/16 inches on a 10 feet span. 

Any floor regardless of concrete or wood has serious gaps and plunges with a profundity of more than 3/16 inches in either way is deemed as an uneven floor for laminate flooring.

Because laminate flooring can withstand a subfloor with a maximum of 3/16 inches deep void/plunges/bumps within 10feet span. 

Therefore, if anyone wants to install laminate flooring on such an uneven floor, he needs to fix the hills and valleys first.

How Flat Does The Floor Need To Be For Laminate?

For a 10 feet radius, the floor needs to be flat within 3/16 inches for laminate flooring to be installed over it. This measurement is only for the floors with slight bumps and gaps. 

Explaining it precisely, if any floor is slightly bumpy and has gaps but the depth of the lumps and gaps are not more than or exactly is 3/16 inches within 10 feet radius then the floor can be considered as a flat floor for laminate.

And this measurement is suggested by most of the manufacturers or professional laminate floor installers. 

Also, this measurement is constant and applicable for most types of flooring. 

Can Laminate Flooring Be Installed Over Uneven Floors? 

Laminate flooring can be installed over uneven floors. But before installing the planks on the floor, you must install interlocking sheets on the floor. 

These interlocking sheets are known as subfloor and they are not attached to the ground. However, these sheets provide quite some flat and even subfloor for laminate flooring to be installed over it. 

However, you are never recommended installing laminate flooring over an uneven floor. 

What Happens If You Put Laminate On An Uneven Floor?

When you put laminate flooring on an uneven floor, clasp between the planks and loosen-up bars occurs when the floor starts to settle down in the new installation. 

Moreover, an uneven laminate floor causes creaking and squeaking sound. As the surface is uneven, so there are voids that are filled up with air. So when someone steps on the floor, the upper flooring gets pressurized and meets the air pockets underneath, causing a sound popping. 

How To Prepare And Level Uneven Floor For Laminate?

Since laminate flooring is installed over two types of the floor which is wooden and another is concrete, so steps for preparing both types of floors are given here.

Wooden floor

Look For Loose/Squeaky Floorboards

Begin the preparation by looking for squeaky or loosen-up boards. 

Secure The Floorboards 

If you find any squeaky/loose board, secure it by attaching the board to the joists underneath with 1-3/4 inch nails or screws. Then, if you find any stray nails, just pull it up or tap it back to the floor with a hammer. 

Identify Higher/Lower Areas

Place a long level on the floor and see if there are any high/low areas or not. 

Sand Down Higher Spots

Then take a hand sander and sand down those high areas until it becomes even like the surrounding surface. 

Clean The Floor

After that, clean the floor very thoroughly. 

Fill Gaps/Dips In Low Area

Fill the gaps in low areas with leveling compound, and feather the perimeters of patched spots as well. let the floor dry. 

Concrete floor

Scrape Away Gunks

First off, scrape out all existing mortars or gunks. 

Identify Higher/Lower Areas 

Place your long level over the floor to spot all the high/low areas, plunges/dips, bumps. 

Grind The High Areas

Then, use a concrete grinder to grind down the high areas and to remove bumps so that it becomes even with the surrounding surface. 

Clean The Floor

After that vacuum the floor to clean it nicely. 

Even Out The Low Area/Gaps

And apply leveling compound in the low areas and gaps/plunges to fill it. Feather the perimeter as well. Let the compound dry.

How Do You Lay Laminate On An Uneven Floor? 

For your convenience, step-by-step guidelines have been provided below. So that you can lay laminate flooring on an uneven floor all by yourself. 

Find The Loose Boards/Adhesives 

If you have a wooden floor, first find the loose or squeaky floorboards. And if you are a concrete floor owner then first you should find all those spots with existing adhesives, cement, or concrete. 

Secure The Loose Boards/Scrape Away The Adhesives 

Now that you have found the loosen-up boards or the boards make a squeaky sound, you need to secure them to the joists underneath with 1-3/4 inch nails or screws. Or if you find any stray nails, just pull them out or use a hammer to hammer them back in their place. 

For concrete floor owners, you have to scrape the existing adhesives from your floor. 

Find Higher/Lower Spots 

Use a carpenter’s level to find out the spots that are higher or lower than the surrounding surface. This step is for both the concrete and wooden floor. 

Even Out The Higher Spots 

Now, for a wooden floor, use a hand sander and sand down all the higher spots you have found. Sand until it becomes level with the rest of the surrounding surface. 

And for the concrete floor, take a hand grinder and grind down all the higher areas. And remove bumps and lumps. Make the floor level and the bumps sit evenly with the rest of the floor. 

Clean The Floor 

Again this step for both types of floors. You need to vacuum the floor thoroughly leaving no dust or debris. 

Fill Lower Areas/Voids 

This step is also for both types of floor. Use floor leveling compound to fill any gaps/plunges on the floor. Feather the edges with a leveling compound too. And let it dry for 24 hours. 

Acclimate The Flooring Planks 

Keep the flooring planks for 48 in the room where they will be installed so that they can get acclimated to the temperature of the room. 

Install The Laminate Planks 

Keeping the required expansion gap, place the planks from the doorway to the back of the room in a perpendicular way to the walls. That’s how to install the first row against the corner wall. 

Make sure that the tongue of the planks is facing the wall and the groove is facing out. Snap the tongue of the planks of 2nd row into the groove of first row planks.

Keep staggering the boards as you are placing more planks. The joints should be kept less than 12 inches distant. And cut the edges of the boards to resize them.  

Keep placing rows of laminate until they cover the room. 

*Generally, laminate flooring requires an underlayment underneath the flooring planks, especially when it is being installed over an uneven floor.

So, if the laminate flooring planks you have chosen don’t have underlayment installed in them, you must lay underlayment sheets. Lay an underlayment after preparing and drying out your uneven floor.*

How Do You Fix An Uneven Subfloor For Laminate Flooring? 

Generally, two types of subfloors are seen, wooden subfloor and concrete subfloor. Therefore, the fixing process of both types has been described below in brief. 

If you have a wooden subfloor, start the fixing process by spotting the higher and lower spots. Depending on the conditions, either sand down the higher spots or place shims underneath the subfloor. Also, fill up the lower areas with leveling compound. And fix the subfloor by making it even. 

For the concrete subfloor, scrape out the adhesives first, then flatten the floor’s higher spots by grinding them. And even out the lower spots with leveling compounds. You can use the concrete compound to make the subfloor smooth. And you’ll be done fixing it too. 

Does Underlayment Help With Uneven Floors? 

Underlayment is one of the most important elements that you cannot miss out while installing flooring over another floor, particularly if it is uneven.

Underlayment over an uneven floor gives a flat and even-looking subfloor surface for the flooring planks there about to be installed. Underlayment supports the flooring planks and as a result, it doesn’t get damaged too soon. 

What Is The Best Laminate Underlay For An Uneven Floor?

Super Velvet is considered as the best laminate underlay for an uneven floor because it has a heavy-weight structure.

Hence, it has a heavy-weight structure, the underlayment will sit properly on the uneven flooring. And will not let the laminate planks to feel any bumps, gaps, or plunges. It will create a smooth surface for the floating planks. 

What Is The Best Laminate Flooring For Uneven Floors?

Laminate planks that are 4 feet long, 3inches wide, and 7mm-12mm thick are the best type of laminate flooring for uneven floors. Thicker laminate flooring planks help to cover uneven floors more. Pergo TimberCraft+WetProtect Laminate Flooring is the best pick for uneven floors. 

When your floor’s dips/bumps are more than 3/16 deep with 10 feet radius, assume it as an uneven floor for laminate. So, always make it level before you install laminate flooring.

Frequently Asked Questions:

Can You Put Laminate Flooring Under Toilet And Sink?

Can You Stack Laminate Flooring to Acclimate?

Does Laminate Flooring Burn?

Does Laminate Flooring Need to Settle?

Do Laminate Floors Fade in The Sun?

How Long Can You Run Laminate Flooring?