How to fix baseboard corners

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How To Fix Mitered Corners On Window Casing

Have you ever walked around your house and noticed random gaps in your window trim or baseboard?

Maybe thats just me that notices that stuff haha! But if you have then it might mean its time to fix those gaps. (Especially those gaps in the mitered corners of your window trim!)

Whether you installed your own window and door trim or a (not-so) professional did, its easier than you think to fix those gaps.

Believe me, we installed all new window trim, door trim, and baseboard in our 1560 square foot 1950s Ranch that we completed remodeled. (You can check out the transformation, how we found the house, and all the tutorials for the work we completed here!)


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And angles can become your worst nemesis! Especially 45-degree angles in mitered joints.

Luckily, I have a cheap (hows a few dollars sound?) and an extremely easy tutorial below to solve all of your mitered corner problems! All it takes is 3 easy steps and the cost of wood filler, sandpaper, and paint.

Once you realize how easy this DIY project is, youll be ready to tackle the rest of the DIY projects in your house and become a super handywoman!

It all starts with this easy project.

Lets dive on in!

How Bad Miters Occur

First off, lets discuss how bad miters occur.

Oftentimes, walls and corners in houses (especially older homes) arent as square as we need them to be to create perfect mitered corners.

As a result, exact 45-degree angles might leave little gaps on corners that arent truly 90-degree angles.

For window trim specifically, there is a trick on how to cut a perfectly mitered corner that I will discuss below. For now, though, lets fix your current problem of gaps in your mitered joints!

Quick Navigation: How To Fix Gaps In Mitered Joints

  1. Tap In & Fill Nail Holes And Gaps In Mitered Corners
  2. Sand The Wood Filler With 180 Grit And Wipe Down The Window Trim
  3. Paint (Or Stain) The Window Trim
  4. Final Thoughts
  5. Related Door & Trim Articles
Level Of DifficultyTime To CompleteEasyA few hoursMaterial ListTool ListWhite Wood FillerPaint traySandpaper (180 grit)2 or smaller Angled PaintbrushCabinet & Trim Paint in your chosen color2 Paint RollerNail set punchHammer

Step One: Tap In & Fill Nail Holes And Gaps In Mitered Corners

The first step to fix gaps in mitered joints is to tap in and fill the nail holes and gaps in the mitered corners.

Since you are taking the time to fix your mitered corners, you might as well fix the nail holes in the trim as well.

All of the nails should be tapped slightly below the surface of the window trim.

That way there is a place for the wood filler to fill in overtop the nails in the holes.

To do this, take a nail set punch and a hammer and lightly tap any nail heads that arent flush with the window trim.

NOTE: The nail set punch is important to use (rather than just tapping the nail head with a hammer directly) because it will sink the nail head below the surface of the trim. That little divot then gives the wood filler a place to sit in. Otherwise, youll be wasting your time because if the nail head isnt sunk into the trim, the wood filler will just break off the nail head.

This nail set punch will do the trick for you, and its rather cheap!

How to fix baseboard corners
The final product beautifully mitered corners in our window trim!

You can take this trick and apply it to any woodworking project you go to tackle next. No need to worry about perfectly mitered corners again!

If you end up tackling this simple DIY project, send me an email with some pictures. Ill feature some of them on this blog post to inspire others!

Catch you in my next post!

how to create flawless miter corners in window trimLove this tutorial? Share it with others so they can fix the gaps in their mitered corners as well!

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How To Fix Gaps In Mitered Joints In 3 Easy Steps (For Flawless Window Trim!)

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