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How to Fix Baseboard With Big Gaps: A Detailed Guide For Beginners

Baseboards are a crucial part of the overall look of the house. But big gaps between baseboards can ruin the overall look. It can also become super noticeable which gradually becomes annoying to look at. 

This makes homeowners wonder, how to fix baseboards with big gaps? 

To fix the baseboard with big gaps you’ll need a miter box and oscillating tool. Start by making a baseboard template and cut the baseboard accordingly. Take out the pieces and install a perfectly cut baseboard piece. Fill the gap with a wood filler and level the baseboard with sandpaper. 

Anyways, that was nothing but just a summary of the entire process. I’ve further elaborated on the process and simplified it for you. 

Keep up with me to know more about baseboards with big gaps!

Fixing Baseboards With Big Gaps: An Easy Process With 9 Steps 

Although fixing baseboard gaps may seem simple at the first glance, it’s not really easy. In fact, it’s one of the most complex procedures when it comes to DIY beginners. 

Because it can get really messy if you’re not careful about the procedure. 

The process itself is quite similar to fixing gaps in laminate or vinyl flooring. Although they’re quite similar, there are a couple of differences. 

Fixing the baseboards that don’t meet up involves some high-end equipment. Other than that, the process is quite long so make sure you’re focused. 

Keep following the baseboard instructions and you’re all good. Simply relax, sit back and go through the entire process. 

Step 1: Gather the Necessary Equipment

The first step is gathering or managing all the important equipment. You don’t want to wander around mid-process for an instrument.

Because otherwise, you’ll become distracted and or more likely to make mistakes. That’s why it’s best to gather them first before you start working on the fix!

Here is all the stuff that you’re looking for-

  • Miter Saw or Miter Box
  • Baseboard 
  • Brad Nailer
  • Oscillating Tool
  • Screwdriver
  • Vacuum Cleaner
  • Plier
  • Putty Knife
  • Tape Measure
  • Strong Glue & Activator
  • Wood filler
  • 180-grit Sandpaper
  • Latex Caulk
  • Wet Cloth
  • Gloves
  • Razor Blades
  • Matching Paint
  • Primer
  • Paintbrush
  • Roller Brush

Grab them as soon as possible and you can get started! 

Step 2: Make A Baseboard Template

If you have managed all the equipment, you can start working on the baseboard. The first thing you’ll have to do is to make a baseboard template. 

You may wonder, why need a baseboard template? You’re supposed to close the gap right? 

It’s because we can’t close a gap that’s already big enough. You can indeed use wood filler in between the baseboard gaps. 

To be frank, it’ll work too. But it’s not a permanent fix. Because if the gap is too big, the wood filler will get cracked over time. 

The trick is to reduce the gap first. And that’s where the template comes in. It’s going to help you create a baseboard piece that sits perfectly in the puzzle.

To do this, take a baseboard piece. It can be any size you want. I recommend a size that’s just enough on both sides. 

Simply put, this template will act as a scale. You’ll later cut the original baseboard according to the template. 

For this step, you’re going to need the miter saw or a miter box. You’ll also need the correct baseboard material. Make sure you have the matching baseboard before you do this. 

Place the baseboard on the miter saw and set the angle to 45 degrees. If you can’t afford a miter saw, use a miter box instead. Cut the baseboard according to the angle. 

Do it on the other side when you’re done. This will give you a baseboard template with two 45-degree angles. 

Step 3: Nail the Baseboard Template On Top of the Baseboard Template

The goal of this step is already explained and mentioned in the name. For this step, a brad nailer will be the only tool that you need. 

You can also use nails and a hammer as an alternative approach to a nail gun. 

Place the baseboard template over the baseboard gap. Make sure the baseboard gap is under the middle of the template. 

When you’re done, use the brad nailer and nail the template on the baseboard. There’ll be one nail on each side of the gap. 

Step 4: Cut the Baseboard With An Oscillating Tool 

The first phase of the process is almost done. All that’s left is to cut the baseboard properly. 

Remember the 45-degree angle from step 2? This is where you’re going to utilize the angle. The point is to cut the baseboard while maintaining that angle. 

To do that, you’ll need an oscillating multi-tool. This cutter will help you cut the baseboard according to the angle. 

Simply place the blade on the template’s side and slowly pierce the baseboard. You must be really careful so take your time. 

You may need to run the blade through the cut multiple times. This will help you get a nice and smooth cut. Make sure you don’t touch the wall with the oscillating tool. 

By now, you should be left with two 45-degree cuts on the baseboard. This method is also used to install a baseboard with no gaps!

This process will spread a lot of dirt and debris around the area. Get the vacuum cleaner and get rid of all the dirt. 

Speaking of oscillating multi-tool, these are what I recommend-

To be frank, both tools are great picks and they work the same. It’ll be more than sufficient no matter which one you choose. 

Step 5: Remove the Template & Baseboard Pieces

With the previous step being completed, the template’s job is done. You also have finished the cutting part of the process. 

Don’t forget to give some parts to yourself for coming this far! 

The second part of the process involves baseboard removal, measurement, and making the right piece. This is going to take a while so stay focused. 

Start by removing the baseboard template. For that, you can use a screwdriver to push out the baseboard. Insert the screwdriver and pull the screwdriver towards you. 

It’ll pry open the template. Take the template out once you’re done. It’ll have pointy nails so bend them and keep them somewhere safe. 

Do the same with the baseboard pieces that you’ve cut. Hold the baseboard so that it stays intact. Keep praying until the pieces come off. 

Do one piece at a time; it’s easier that way. 

But you’re not done just yet. The walls may have nails stuck in them. If there are nails, you’ve got to remove them first. 

Use a plier to remove the nails from the walls. Do it slowly so that it doesn’t damage the wall. You can hold a putty knife against the wall as you pull the nails. 

This will prevent possible wall damage. Vacuum the entire area again to clean all the dirt.

Step 6: Measure The Total Gap In-between the Baseboard

By now, you have a huge gap in the baseboard. In this step, you’ll be taking a couple of measurements until you’re right. 

Take a tape measure and place it on one side of the gap. It’s best not to use the edge of the tape measure. 

Use the 2-inch or 3-inch mark for a more accurate measurement. Note down the length of the gap. 

You can also use a baseboard piece to measure the gap. Place it on top and mark the longest length with the pencil. 

If you’re done with the measuring, head to the next step. 

Step 7: Cut & Make a Baseboard Piece

This is the toughest bit and the most time-consuming part of the procedure. This will take a lot of time as you may go through some trial and error. 

Take a scrap piece of the baseboard and place it on the miter saw again. Maintain the 45-degree angle and cut the first side of the baseboard. 

Measure the longest length and mark the end with a pencil. Afterward, place the other side on the miter saw and cut it. 

Take this piece and place it in the gap. It should fit perfectly. If it doesn’t, repeat the process again. 

The upper part may be a perfect fit while the lower may not be. It happens when the cut itself isn’t perfectly vertical. 

In that case, you’ll have to adjust the length. If it’s too tight or big for the gap, draw a line using a pencil. Cut it again until it becomes the perfect size. 

After 2 or 3 tries, you should have a perfectly cut baseboard piece. You can go to the next step if it sits perfectly in between. 

Step 8: Connect the Baseboard with Glue & Activator

The remaining steps of the fix including this one are simple and easy. Take out the piece that you’ve cut and put some glue on the 45-degree cuts.

Take the activator and spray only one side. This will help you adjust the piece without gluing it instantly. 

Connect the baseboard piece to that side. You can then begin spraying the activator on the remaining end. Connect the baseboard to the piece and this step is done!

Take the brad nailer and nail the baseboard 4 times. There will be 2 nails beside each gap to secure the baseboard. 

Step 9: Level the Baseboard with Wood Filler and Sandpaper

Thanks to the perfect baseboard piece the gap is super tiny. Fill the baseboard gap with a wood filler to seal the deal!

Carefully place the filler over the gap and the nails. Use a razor blade to spread the filler as evenly as possible. 

Wait for 2-3 hours and you can start sanding. Use 180-grit sandpaper to level the baseboard. This will create a lot of dirt and debris so vacuum the area afterward. 

You can now caulk the in-between of the baseboard and wall. Caulking is super important even when you’re fixing gaps between the baseboard and the floor

To get rid of the excess caulk, you can use a rug. 

Final Step: Paint the Baseboard For a Nice Finish

The last step is to paint the baseboard. Get some matching paint and some paintbrush. 

You can also use a roller paint brush for a better finish. Don’t forget to prime the paint since you used a wood filler. 


What to put in the baseboards when a gap is big?

You can put some waterproof latex caulk or wood filler in between the baseboard gap. But this isn’t always the best option. Because over time, it can get dry and crack itself if the gap is too big. It’s better to reduce the gap by putting a baseboard piece first. Applying caulk becomes effective.

How do you fix separating baseboards from the wall?

You can easily fix separating baseboards from the wall by using caulk. There are some great waterproof caulks that are paintable. You can also use some brad nailer to nail some parts of the baseboard. But caulks will easily fill up the gap in between. Wipe the excess caulk off when you’re done. 

What causes gaps in baseboards?

There can be gaps in baseboards due to contractors doing a poor job. It can also happen due to excess moisture. It can rot the joists of the floor which can then make the floor sag. Walls separating from the baseboards can happen due to a bad foundation. Luckily, fixing the gaps is easy. 

Final Thoughts

That was all I could gather and explain on fixing baseboards with big gaps. I hope that my process was insightful enough to solve your dilemma. 

If you think the process is too hard or bothersome, don’t hesitate to call experts. They’ll inspect and fix the problem right away!

Finally, have a nice day!