How To Install Baseboard Molding On Uneven Floor

Baseboard molding is an essential addition to any classy home. Without it, your floors and walls will look unfinished, and you’ll never achieve that flattering style seen in interior design magazines. But how can you make your house look neat if you have uneven floors? After all, baseboards aren’t supposed to look all wavy. Luckily, there is a way to install them.

Use a level to install baseboard molding on your uneven floor in a neat, straight line. Fill any gaps with caulk, then paint the baseboard in the desired shade. Do the same to fill any gaps between the molding and uneven walls.

Should Baseboard Be Level or Follow The Floor?

The million-dollar question you might be asking right now is the one above, and there is only one answer – the baseboard should always be level.

While you could follow the floor to make installation easier, the upper edge of the baseboard would look all wavy against the wall. In other words, if guests and potential buyers wouldn’t notice the uneven floors without the baseboard, a molding that follows the floor would give away the defect at a glance. 

Sure, installing a level baseboard on uneven floors requires not only skills and concentration but also a way to deal with the gaps. That’s where caulking comes in. Once you fill the gaps and paint the baseboard, the finish will give your room a neat look and make your floors look even.

With this in mind, let’s find out how to install the baseboard and give a 5-star appearance to your interior.

Things You Will Need To Install Baseboard On Uneven Floor 

Installing a baseboard is generally so easy that even beginners can complete the project successfully. However, you can’t achieve success without the tools and materials below.

Tools Needed

  • Brad nailer
  • Caulking gun
  • Putty knife 
  • Palm sander
  • Vacuum cleaner

Materials Required

  • Wood baseboards
  • Paintable caulk 
  • Primer 
  • Paint 
  • Painter’s tape
  • Brad nails
  • Sandpaper 
  • Protective equipment
  • Tape measure

For Cutting Baseboards

  • Miter saw or miter box with a handsaw 
  • Marking knife
  • Carpenter’s square

DIY: Installing Baseboard Molding On Uneven Floor in 5 Easy Steps

Successful placement of baseboards creates a level line against the wall while the boards are flush against the floor. On uneven floors, you may sometimes have to cut the boards along the bottom to achieve the result.

Step 1 – Measure the walls and cut the baseboards

The first thing to do when installing baseboards on any type of floor is to measure the wall length and cut baseboard lengths accordingly.

Grab the tape measure and write down on paper the length of each wall. Make a sketch to see the points where baseboards meet at an angle and where you should cut the ends.

Then, cut the baseboards to dimension using a miter saw (or use a miter box and handsaw if you don’t have the power tool). All boards that meet in the corners of the room must be cut at a 45-degree angle to ensure a flush fit. 

All ends have a 90-degree angle. Don’t worry if your wall isn’t level; we will show you how to deal with it below.

Step 2 – Install the baseboard 

There are two ways to install baseboards on uneven floors. You could either install the baseboard touching the floor’s highest point, then fill the gaps with caulk, or you could cut the baseline for a flush fit that needs no caulking. We describe both methods below so you can use the one that suits you best.

Method 1 – Fill the gaps with caulk

Place the baseboard against the wall, making sure it touches the floor. Use a level to draw a straight line on the wall from the board’s highest point. At this stage, the baseboard is flush with the highest point of the floor, whereas you can see gaps between the molding and the lower areas of your uneven floor.

Use a brad nailer and brads to install the molding, aligning the top with the level line on the wall. 

Once you’ve installed all baseboards, fill the gaps with paintable caulking. If the wall is also uneven, use caulking to fill those gaps, too. Alternatively, if the floor is only slightly uneven, you can cover the gaps with shoe molding.

Method 2 – Cut the baseboard bottom

If you’re afraid that caulk could crack in time (which is probable), you can solve the issue by tailoring the baseboard’s bottom to fit your floor perfectly.

To do that, place the baseboard on the wall, about a ¼ of an inch above the floor, and mark the position. Use a level to draw a straight line on the wall and fix the board with nails. This is only a temporary fix, so don’t use brads at this stage and only use enough nails to prevent the board from moving.

Fix a pencil to a compass and place one point of the compass even with the floor. Position the pencil end slightly above the baseboard’s bottom line. Hold the compass firmly from the center to prevent the points from moving, then drag it along the floor.

As the floor level changes, so will the line on your baseboard – showing you exactly where to cut the material for a flush fit.

Remove the boards from the wall, paying attention not to damage it as you’re extracting the nails, then cut the bottom following the line you just drew.

Install the baseboard flush against the floor, fixing it with brad nails. You can then use plastic wood or epoxy filler to repair any nail holes.

Step 3 – Fill the uneven gaps

While both methods above tell you how to install baseboard molding flush with the floor and level on top, you may still spot gaps between the board and the wall. Use paintable caulk to fill all these gaps.

Step 4 – Fix the ends 

We mentioned above that some walls don’t have straight edges. You can use the compass method described above to draw a line and cut the baseboard end so that it is flush against the wall.

Step 5 – Paint the baseboards

To finish your work, paint the baseboards in the desired shade. White is perhaps the most elegant and timeless option, but you could also paint them in the color of the floor or in a shade contrasting the walls.

For a flawless finish, sand the surface first with fine-grit sandpaper. Remove all dust with a vacuum cleaner, then wipe the boards with a rag.

Apply wood primer and let it dry for a couple of hours before applying the first coat of paint. We recommend water-based paint products, but you can use solvent-based paint, too, if you wish. Let the first coat dry for about four hours if it’s water-based and about 6-8 hours if it’s solvent-based.

Use fine-grit sandpaper to even out the surface, then apply a second coat of paint. Let it dry and cure as instructed on the tin. You can then apply a waterproof topcoat if you want a longer-lasting finish.

While you can use any paint product you want, eggshells, satin, and gloss finishes are your best bet when it comes to baseboards.

How To Fill Large Gaps in Baseboard Corners

The methods above won’t work to cut the baseboard corners flush against the wall, so you could end up with larger gaps to fill if the walls aren’t even.

The easiest way to fill these gaps is with spackling compound. Wood filler or drywall joint compound work in the same way.

Use a caulking gun for an accurate product application, then level the top edge with sandpaper.


Still have questions? We have some answers for you.

Do you nail baseboard to studs?

Yes, baseboard molding typically attaches to wall studs and to the floor plate.

Can you scribe MDF?

You can scribe MDF, but the procedure is often not needed. That’s because MDF isn’t too rigid, and you can simply miter its corners.

To End

Installing baseboard molding on uneven floors becomes child’s play once you learn the methods above. Which installation method would you pick? Tell us in a comment.

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