How to Install Baseboards on Inside Corners

Inside corner of a baseboard
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  • 01 of 10

    Mark Direction of Cut on First Baseboard

    Mark Cut Direction on First Baseboard
    Lee Wallender

    Press the uncut first baseboard tight into the corner.  It doesn't matter if you begin with the left or right side; here, the first piece is on the right side.


    You will be cutting the baseboard at a roughly 45-degree angle. Mark the general direction of your first cut on top of the baseboard.  It's just a little reminder that will help you know which direction to cut when you get to the miter saw.  

    Tools and Materials

    • Baseboard: You can buy this in the form of real wood, medium density fiberboard (MDF), or plastic.  
    • Electric Miter Saw: It's highly recommended to buy, rent, or borrow an electric miter saw. Cuts are not only faster but more accurate.
    • Electric Brad Nailer: If you don't have a nailer, don't want to buy one, and only have 30 linear feet or so (or less), then you can get by with a hammer, finish nails, and a nail set. Though it's recommended to have the electric tool over the manual one.
    • Pencil
    • Measuring tape
    • Stud finder
    • Painter's tape
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  • 02 of 10

    Set Saw Before Cutting First Baseboard

    Set Saw Before Cutting First Baseboard
    Lee Wallender

    Move your miter saw's fence to a 45 degree-ish position (see below), conforming to the line you earlier drew.

    Tip: Not Quite 45 Degrees

    While it seems like 45 degrees should work, cutting it just a hair less than 45 degrees (44, but no less) produces a better fit later on when you piece up the two sides of the baseboard. 

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  • 03 of 10

    Cut the First Baseboard

    Cut the First Baseboard
    Lee Wallender

    Cut the baseboard. Make sure you're wearing safety glasses and hearing protection.  With electric miter saws, it's not a "good idea," it's downright critical.

    Tip: Positioning the Material

    Are you left-handed?  Right-handed? If you are right-handed like in this picture, hold the workpiece with your right hand and operate the saw with your left. It's not a natural position but it produces a better cut than turning the baseboard upside-down and cutting it that way and no risk of cutting it the wrong direction.

    Continue to 4 of 10 below.
  • 04 of 10

    Remove Melted Plastic From Cut Area

    Remove Melted Plastic from Baseboard
    Lee Wallender

    Real wood is real, and a lot of homeowners prefer it because of the idea that it is real.  But how does it function, as opposed to MDF or plastic baseboards?

    As long as the baseboard will be painted, you might as well buy the plastic stuff.  Painted wood and painted plastic look exactly the same but plastic bases will never rot.

    Tip: How to Remove Plastic Burrs

    One unfortunate side effect of cutting baseboards is the lip of melted plastic caused by the friction of the saw blade.  Wait at least one minute after cutting. By then, the plastic will be brittle enough that it easily snaps off.  If you try to do it before then, you might burn your fingers and the lip will not remove as cleanly.

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  • 05 of 10

    Set Saw for the Second Baseboard

    Set Saw Before Cutting Second Baseboard
    Lee Wallender

    Move your saw's fence to the opposite 45 degree-ish side. The same idea of cutting just a degree short applies here.

    Now, as a right-handed person, you will find that the cut will be easier and safer.

    Tip: Electric, Not Manual

    It's great to have a manual miter saw and box around. They work well for angled cuts on small material, like quarter-rounds. But larger pieces don't fit in most miter boxes. The main reason, though, is that the work piece wiggles around when hand-cutting, thus producing a less-than-sharp cut.

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  • 06 of 10

    Cut the Second Baseboard

    Cut the Second Baseboard
    Lee Wallender

    Cut your second baseboard. Let the plastic burrs cool (as applicable), then clean up the cut edge, as before. 

    Tip: Change to a Fine Blade

    The blade that came with your electric miter saw may not be appropriate for trim. If it's a general-purpose blade, it probably won't cut trim all that well. Instead, invest in what is called a ​finish miter saw blade

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  • 07 of 10

    Measure Straight Cuts in Place

    Measure Your 90 Degree Cuts on Site
    Lee Wallender

    Use the opposite end of one of your boards and butt it up flat against a piece of molding. Take the baseboard from the miter saw, back to the site, and measure it there.

    Tip: Measure in Place

    Why measure something with a tape measure when you can measure the actual material on site? You can never measure as accurately with a tape measure as you can when laying the baseboard against the place where it needs to be cut. 

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  • 08 of 10

    Set the Baseboards Together

    Baseboards Fit Together
    Lee Wallender

    Voila! This is how the two baseboards should look when they come together.  

    Tip: Corner Fixes Don't Work

    So maybe the angles are wrong. Or maybe the angles are right, but they're just a bit short of each other. Should you fix it with wood filler or caulk?  

    No. Those patches will eventually pull apart. Instead of immediately buying new baseboards, see if you have foot-long or greater scrap pieces laying around. The more invisible fix is to cut out about 8" to 10" from the middle of the baseboard with two parallel 45 degree cuts. Then cut your scrap piece to fit that section. It's called a scarf joint.

    Continue to 9 of 10 below.
  • 09 of 10

    Find and Mark Location of Wall Studs

    Mark Location of Wall Studs
    Lee Wallender

    With a stud finder, find your wall studs and mark their locations with squares of painter's tape.

    Tip: Using Stud Finders

    Studs usually will run every 16 inches on-center. Your stud finder probably won't detect studs at corners; you'll just have to know that corners are guaranteed to always have studs.

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  • 10 of 10

    Nail the Baseboards in Place

    Nail Baseboards in Place
    Lee Wallender

    Tack the baseboard into place by shooting brads at an angle into the wall where the studs are located.

    Tip: Go Electric

    Like the electric miter saw, this is another instance where the electric tool works far better than the manual one, and not just because it saves you work.

    With an electric nailer, you can hold the baseboard in place and affix it instantly—without risk of moving the baseboard around.  By contrast, when you nail manually, every strike on the hammer is another chance for the baseboard to rattle out of position.