Laminate Over Uneven Subfloor? (7 Steps!)

Laminate Flooring Over an Uneven Subfloor: 7 Essential Steps

I’m a flooring contractor, and I’ve seen it all when it comes to floors.

Laminate flooring is super popular, right? It’s affordable, looks great, and seems easy to install.

But, here’s the thing: many homeowners run into a snag when they discover their subfloor isn’t perfectly even.

Dips, bumps, squeaks – the horror!

Don’t worry, though. I’m here to tell you that installing laminate over an uneven subfloor is totally doable.

You just need the right approach.

Think of your subfloor as the foundation of your beautiful new laminate floor.

If it’s wonky, your finished product will be too.

Ignoring an uneven subfloor is like building a house on sand.

It might look okay at first, but problems will surface later, like:

• Uneven Wear: High spots will wear down faster.

• Gaps: Planks can separate, creating ugly gaps.

• Squeaks: Annoying noises that will drive you crazy.

• Damage: The locking mechanisms can break under stress.

That’s why I’ve put together this guide with 7 essential steps to help you tackle this challenge.

I’ll walk you through everything, from assessing the subfloor to those all-important finishing touches.

Follow these steps, and you’ll end up with a beautiful, durable laminate floor that you can be proud of.

Ready to get started? Let’s dive in!

Step 1: Assess the Condition

of the Subfloor

Alright, first things first: detective work! We need to figure out just how uneven your subfloor really is.

This isn’t just about eyeballing it. You need to get down and dirty with some tools and careful observation.

Visual Inspection:

Start with a good, old-fashioned look-see. Scan the entire subfloor.

Are there obvious dips or humps?

Pay close attention to areas where you suspect there might be problems, like around doorways or near walls.

The Level Test:

Grab a long level (at least 6 feet is ideal). Place it on the subfloor in various directions.

Do you see any gaps between the level and the floor?

That’s a sign of unevenness.

For a more precise measurement, use a straightedge along with a feeler gauge.

This will allow you to measure the exact height of any gaps.

Spotting the Signs:

What are some telltale signs of an uneven subfloor? Here are a few:

• Dips: Obvious low spots that you can see or feel.

• Bumps: High spots that can cause the floor to feel uneven.

• Squeaks: A classic sign of movement and instability.

• Cracks: These can indicate structural issues.

• Loose Fasteners: Popped nails or screws can be a sign of movement.

Know Your Subfloor:

Identifying the type of subfloor is key. Is it plywood, concrete, OSB, or something else?

Each material has its own unique characteristics and potential problems.

• Plywood: Can warp, delaminate, or develop soft spots due to moisture.

• Concrete: Can crack, crumble, or have uneven surfaces.

• OSB: Similar to plywood but more susceptible to moisture damage.

The condition of your subfloor matters, too. Is it solid and stable, or is it damaged or deteriorating?

Documenting Your Findings:

As you assess the subfloor, take notes and pictures.

Create a simple map of the room and mark any problem areas.

Note the type of subfloor, the severity of the unevenness, and any other relevant details.

This documentation will be invaluable when you start planning your leveling strategy.

This is an example table of how the documentation can look like:

Pro Tip: Don’t skip this step! A thorough assessment will save you time, money, and headaches in the long run.

Step 2: Gather Necessary Tools

and Materials

Okay, now that you know what you’re dealing with, it’s time to gather your supplies.

Having the right tools and materials on hand will make the job much easier and more efficient.

Here’s a comprehensive list of what you’ll need:

Tools:

• Level: A 6-foot level is ideal for checking for unevenness.

• Straightedge: Use this with a feeler gauge to measure gaps.

• Measuring Tape: Essential for accurate measurements.

• Pencil: For marking problem areas and cutting lines.

• Trowel: For applying leveling compound.

• Mixing Bucket: For mixing leveling compound.

• Drill/Screwdriver: For securing plywood or fasteners.

• Circular Saw/Jigsaw: For cutting plywood or laminate planks.

• Hammer: For tapping laminate planks into place.

• Tapping Block: Protects the laminate edges during installation.

• Pull Bar: Helps tighten the last row of planks.

• Spacers: To maintain consistent expansion gaps.

• Utility Knife: For cutting underlayment and other materials.

• Safety Glasses: Protect your eyes from debris.

• Dust Mask: Protect your lungs from dust.

• Knee Pads: Save your knees!

Materials:

• Leveling Compound: Fills low spots and creates a smooth surface.

• Plywood (if needed): For raising low areas or replacing damaged sections.

• Underlayment: Provides cushioning, moisture protection, and sound dampening.

• Laminate Flooring: Choose your desired style and color.

• Fasteners: Screws or nails for securing plywood.

• Wood Filler: For filling gaps or imperfections in plywood.

• Construction Adhesive: For securing plywood or underlayment.

• Baseboards/Quarter-Rounds: For a finished look.

Sourcing Your Supplies:

You can find most of these items at your local hardware store or home improvement center.

Online retailers are also a good option, especially for specialized items or bulk purchases.

When choosing materials, consider both cost and quality.

Don’t skimp on essential items like leveling compound or underlayment.

Pro Tip: Make a list and double- check it before you head to the store. It’s always better to have too much than not enough!

Step 3: Prepare the Workspace

Alright, you’ve got your tools and materials. Now it’s time to get the room ready for the transformation!

A clean, well-prepared workspace will make the installation process much smoother and safer.

Clearing the Area:

First things first: empty the room. Remove all furniture, rugs, and other obstacles.

If you can’t remove everything, cover the remaining items with plastic sheeting to protect them from dust and debris.

Next, remove any existing flooring. This could be carpet, tile, vinyl, or even old laminate.

Use the appropriate tools to remove the old flooring and dispose of it properly.

Safety First:

Before you start working, put on your safety glasses and dust mask.

Demolition work can create a lot of dust and debris, so protect your eyes and lungs.

Ensure proper ventilation by opening windows or using a fan.

Acclimating the Laminate:

This is a crucial step that many people overlook.

Laminate flooring needs to acclimate to the room’s temperature and humidity before installation.

Stack the boxes of laminate in the room where they will be installed for at least 48-72 hours.

This will allow the planks to expand or contract to their natural size, preventing future problems like gaps or buckling.

Cleaning the Subfloor:

Once the room is clear and the laminate is acclimating, thoroughly clean the subfloor.

Sweep, vacuum, and even mop the subfloor to remove any dust, dirt, or debris.

A clean surface will ensure proper adhesion of leveling compound and underlayment.

Pro Tip: Take your time with this step. A well-prepared workspace will make the installation process much easier and more enjoyable.

Step 4: Level the Subfloor

Okay, this is where the real magic happens! Leveling the subfloor is the most critical step in ensuring a successful laminate installation.

There are a couple of common methods for leveling a subfloor: using leveling compound and using plywood shims.

I’ll walk you through both.

Leveling Compound:

Leveling compound is a self-leveling mixture that you pour onto the subfloor to fill low spots and create a smooth, even surface.

Here’s how to use it:

1. Prepare the Surface: Make sure the subfloor is clean and free of loose debris. You may need to prime the subfloor with a special primer to ensure proper adhesion of the leveling compound.

2. Mix the Compound: Follow the manufacturer’s instructions for mixing the leveling compound.

   Use a mixing bucket and a drill with a mixing paddle.

   Add water gradually until you achieve a smooth, pourable consistency.

3. Pour and Spread: Pour the leveling compound onto the low spots of the subfloor.

   Use a trowel to spread the compound evenly and feather it out to blend with the surrounding surface.

4. Allow to Dry: Let the leveling compound dry completely according to the manufacturer’s instructions.

   This could take several hours or even overnight.

5. Check for Evenness: Once the leveling compound is dry, check for evenness with your level or straightedge.

   If necessary, apply a second coat of leveling compound to fill any remaining low spots.

Plywood Shims:

For larger areas of unevenness or for raising the entire subfloor, you can use plywood shims.

Here’s how:

1. Measure and Cut: Measure the low areas of the subfloor and cut plywood shims to fit.

   You can use different thicknesses of plywood to achieve the desired level.

2. Secure the Shims: Attach the plywood shims to the subfloor with construction adhesive and screws.

   Make sure the shims are flush with the surrounding surface.

3. Fill Gaps: Fill any gaps between the shims and the subfloor with wood filler.

   Sand the wood filler smooth once it’s dry.

Sanding High Spots:

If you have high spots on your subfloor, you can sand them down with a belt sander or a floor sander.

Be careful not to sand too much, as this could weaken the subfloor.

Troubleshooting Tips:

• Leveling Compound Cracking: This can happen if the leveling compound dries too quickly or if the subfloor is too absorbent.

  To prevent cracking, prime the subfloor before applying the leveling compound and keep the room humid while it dries.

• Leveling Compound Not Self- Leveling: This can happen if the leveling compound is too thick.

  Add a little more water to the mixture until it reaches the desired consistency.

• Plywood Shims Not Flush: Make sure the plywood shims are securely attached to the subfloor and that they are flush with the surrounding surface.

  Use a level to check for evenness.

Pro Tip: Don’t rush this step! Take your time and make sure the subfloor is as level as possible before moving on to the next step.

Step 5: Install Underlayment

Alright, your subfloor is now nice and level. Great job!

Now it’s time to install the underlayment.

Underlayment is a thin layer of material that goes between the subfloor and the laminate flooring.

It provides a number of benefits, including:

• Cushioning: Makes the floor more comfortable to walk on.

• Moisture Protection: Prevents moisture from the subfloor from damaging the laminate.

• Sound Dampening: Reduces noise from footsteps and other sounds.

• Smoothing: Helps to smooth out minor imperfections in the subfloor.

There are several different types of underlayment available, including:

• Foam: A common and affordable option.

• Cork: A more expensive but eco-friendly option.

• Rubber: Provides excellent sound dampening.

• Combination: Some underlayments combine different materials for enhanced performance.

When choosing an underlayment, consider your budget, the specific needs of your flooring, and any local building codes.

Installing the Underlayment:

1. Roll Out the Underlayment: Start by rolling out the underlayment across the subfloor.

   Overlap the seams by a few inches.

2. Trim to Fit: Use a utility knife to trim the underlayment to fit the room.

   Leave a small gap around the perimeter of the room for expansion.

3. Tape the Seams: Use seam tape to secure the seams of the underlayment.

   This will prevent moisture from seeping through.

4. Secure the Perimeter: Use construction adhesive or staples to secure the underlayment to the subfloor along the perimeter of the room.

Pro Tip: Choose an underlayment that is specifically designed for laminate flooring.

Some underlayments are not compatible with laminate and can cause problems down the road.

Step 6: Lay the Laminate Flooring

You’ve prepped the subfloor, laid the underlayment – now for the main event: laying the laminate!

This is where your room really starts to transform.

Here’s a step-by-step guide:

1. Plan Your Layout: Before you start laying the laminate, take some time to plan your layout.

   Consider the direction of the planks, the location of doorways, and any other special features of the room.

   Generally, it’s best to run the planks parallel to the longest wall in the room.

2. Start in a Corner: Begin laying the laminate in a corner of the room.

   Make sure the first row of planks is perfectly straight and aligned with the wall.

   Use spacers to maintain a consistent expansion gap between the planks and the wall.

3. Lock the Planks Together: Most laminate flooring uses a click-lock system to join the planks together.

   Follow the manufacturer’s instructions for locking the planks together.

   You may need to use a tapping block and a hammer to gently tap the planks into place.

4. Cut the Planks: When you reach the end of a row, you’ll need to cut the last plank to fit.

   Use a circular saw or a jigsaw to cut the plank.

   Be sure to measure carefully and cut the plank at the correct angle.

5. Stagger the Seams: To create a more visually appealing and structurally sound floor, stagger the seams between the rows of planks.

   Use the cut-off piece from the end of one row to start the next row.

6. Work Your Way Across the Room: Continue laying the laminate, row by row, until you’ve covered the entire floor.

   Use a pull bar to tighten the last row of planks against the wall.

7. Handle Doorways and Transitions: When you reach doorways or transitions between rooms, you’ll need to use transition strips.

   These strips cover the gap between the laminate flooring and the adjacent flooring.

Pro Tip: Take your time and be patient. Laying laminate flooring can be a bit tedious, but the results are worth it.

Step 7: Finishing Touches

You’re almost there! The laminate is down, and your room is looking fantastic.

Now it’s time for those finishing touches that will really make your new floor shine.

Trimming Excess Underlayment:

Use a utility knife to trim any excess underlayment that is sticking out from under the laminate.

Installing Baseboards or Quarter-Rounds:

Baseboards and quarter-rounds are decorative moldings that cover the expansion gap between the laminate flooring and the wall.

They add a finished look to the room and protect the walls from damage.

Attach the baseboards or quarter- rounds to the wall with nails or construction adhesive.

Cleaning the Floor:

Use a soft broom or a vacuum cleaner to remove any dust or debris from the new laminate floor.

Then, use a damp mop to clean the floor with a laminate floor cleaner.

Avoid using excessive water, as this can damage the laminate.

Allowing the Floor to Settle:

Give the floor a few days to settle and acclimate before putting heavy furniture back in the room.

This will allow the laminate to expand or contract as needed.

Pro Tip: Invest in a good quality laminate floor cleaner.

Avoid using harsh chemicals or abrasive cleaners, as these can damage the finish of the laminate.

Conclusion

Wow, you did it! You’ve successfully installed laminate flooring over an uneven subfloor.

That’s a major accomplishment!

Remember, each step is crucial:

• Assessment: Know your enemy (the unevenness!).

• Tools & Materials: Be prepared.

• Workspace Prep: A clean space is a happy space.

• Leveling: The foundation for success.

• Underlayment: Protection and comfort.

• Laying the Laminate: The main event!

• Finishing Touches: The cherry on top.

Take your time, be patient, and don’t be afraid to ask for help if you need it.

With the right approach and tools, anyone can create a beautiful and functional flooring solution that enhances their living space.

Now, step back, admire your handiwork, and enjoy your new laminate floor! You earned it!

Learn more