I get a lot of requests about installing baseboards. No one taught me how to install baseboards or any trim work for that matter. It’s something I figured out on my own via trial and error.

I learned years ago before there was YouTube, even before Google became a thing. I studied pictures and I read books. I would watch finish carpenters work on job sites that I was managing and if they let me help, I’d help.

If I can do it, You can do it

I didn’t start with the best tools either. In fact, if you don’t count the $5 miter box, my first miter saw was a $25 Craigslist find and was missing its dust collection bag. I wrapped a large black tube sock where it should be and tied an elastic hair band around the tube so it didn’t blow off. I wish I had a picture. It didn’t make fancy compound cuts. It didn’t slide. It didn’t have a large blade or shoot a laser guide for cutting.

But you know what? I was poor and I loved that saw. I loved that I was able to make my own stuff. I loved that I could add character to my home with trim and install taller baseboards and on my own terms with little money (wood was cheaper then).

This leads me to two things about installing baseboards

First, if I was able to learn how to install baseboards with little resources. You can learn even faster and be even better.

Second, because I am self taught I may not do things the same way a professional would. But I do think my finishes look professional.

If that makes sense.

Some of the links I share are affiliate links, and if you purchase through them it won’t cost you any extra, however, I may be paid a small commission. That small support helps me keep the lights on and we appreciate all of it.

Pull away shot of the baseboard installation in the closet for the fall 2022 one room challenge. The closet is painted a gray green with dentil molding crown and Ikea pax closet systems made to look built in. There is a persian rug from Target on the floor.
Installing baseboards doesn’t have to take all day if you follow my tips.

My favorite tools for installing baseboards

  1. FatMax Measuring tape – I have these in every length, I leave one in the room and one by the saw
  2. Notepad – honestly I just use my phone notepad or scrap paper
  3. An angle finder or protractor – I have a digital and an old school one for when I run low on batteries
  4. Level – I shuffle around with this torpedo level everywhere I go
  5. Scribing tool – I don’t scribe everything, just major gaps when I’m installing baseboards
  6. Screws
  7. Drill or impact driver
  8. Painters tape – I like the blue stuff but any tape will do
  9. Wood glue
  10. Miter saw
  11. Finishing blade
  12. Utility knife

Where and How to Measure for Baseboard Installation

This week for the One Room Challenge I am focusing on installing the baseboards in our closet. I have a system for measuring a room and writing my measurements down.

Table of Contents for Installing Baseboards

  1. Measuring with a System
  2. Measuring Inside Corners
  3. Measuring Outside Corners with a Bullnose
  4. Recording Your Measurements
  5. Prepping your baseboards
  6. Choosing your nail size
Measuring tape against the baseboards showing the direction I work around a room; picture is of our closet with an Ikea pax organizing system in place.
I work counter clockwise around the room – always doing it the same way takes the guessing work out of which board goes where

Measure systematically and from the right spot

I start in one spot, usually the left side of a door casing. I measure each wall by placing my tape measure along the wall but against the floor. This is because it’s where the baseboard will be applied.

I don’t measure the top or the middle because my baseboards won’t be going there.

I am right handed and so I install baseboards counter clockwise around a room. This is because I cope my interior corners. This allows me to make my copes comfortably for my right handedness. If you are left handed you may want to consider working clockwise around a room. 
The bend of a measuring tape placed on the inside corner during baseboard installation.
Dealing with the bend in the measuring tape can often lead to mis-cuts avoid this with my tip

Measuring Inside Corners for Baseboards

Measuring from one inside corner to another inside corner can be tough. This is because when you reach the inside of the opposite corner you end up bending your tape measure. As you get better at installing and knowing your tape measure you won’t always use this next tip.

Tape marks the spot. Place a piece of tape on the floor and measure from the inside corner to 10" to get an accurate inside corner to inside corner measurement when installing baseboards.
Tape is easily removed and so great for making marks on areas where you can’t

Measure from the left inside corner out 10″ towards the right corner, I place a piece of tape on the ground and mark where the 10″ falls with a line. Then I place the end of my tape into the opposite corner, measure up to my mark and add 10″. Doing this will give you an accurate measurement every time. It’s especially useful for measuring crown molding.

Measure from the inside corner to the 10" mark on your tape to get an accurate measurement of the wall for installing your baseboards
Now I can add 10″ to 94 1/2″ and get an exact measurement from inside corner to inside corner

Measuring Outside Corners with a Bullnose

I converted the only bullnose corner in this closet in to a 90 degree corner. Those are easy to measure just place the measuring tape in the inside corner and pull towards the outside corner…or from outside corner to outside corner. I don’t think a picture is necessary…However, bullnose corners are a whole other animal.

I am slowly getting rid of every bullnose though because I hate them. So, I am showing you how I measure to a bullnose corner in another area of my home.

They make preformed bullnose corners that you can glue on to your bullnoses, they are kind of a luxury item and the price adds up pretty quickly if you have a lot of corners. I like to make my own. They aren’t perfect curves, but they get the job done.

Measure to the shadow line. It takes a close look to figure out where that is, but it’s where the metal begins its curve beneath the drywall compound. It creates this shadow line or slight change in color because of the way the light is hitting the curve.

There are two spots on every bullnose. The right side and the left side. The cut is a 22.5 degree cut on your miter saw for all three pieces of the corner. This is because 22.5 + 22.5 on the left side = 45 and then 22.5 + 22.5 on the right side = 45, then 45 + 45 = 90 and that is your corner.

When I am measuring a bullnose corner, I always mark on the wall where I measure. Then, I write the measurement of the bullnose in the middle between my two marks. I will be caulking and painting after anyways, so might as well. It makes measuring the smaller piece (which isn’t always the same) and then installing it a lot easier later.

Marked with a circle the 22.5 degree miter and the shadow line are easier to recognize.
22.5 degrees is what I set my miter saw to cut for bullnoses

If you hate bullnose corners as much as I do, check out my wainscoting tutorial where I show how I square off my corners.

Recording Your Measurements when Installing Baseboards

This may look like a foreign language at first. However, the lines are drawn in the direction my blade is going to cut the angle that I need. If I just write the measurements down without my hashmarks I am likely to forget an angle or two.

Scrap piece of white paper with measurements written down and a hash marking system or coding for cutting baseboards for installing. A bright yellow ticonderoga pencil lays next to it and there is a black background.
It may look random but those hash marks have a deeper meaning

By utilizing this shorthand for installing baseboards I am able to measure all my walls and rooms at once – just make sure you label each room. Then I can go and cut all of my baseboards in one session.

My shorthand hashmark measuring system

  • | is for a butt cut (zero degree cut/straight cut)
  • \ right 45 degree cut or another angle but I will write it down next to it like this: \22.5
  • / left 45 degree cut or another angle but I will write it down next to it like this: /22.5
panel molding trim is sitting against the fence of the miter saw for a left inside 45 degree miter cut
See the direction the blade is? \ this mark correlates with the direction of the blade
The beauty of writing my measurements like this, is when I am using my phone notepad there are keystrokes that correlate with my hashmark system. 
Illustrating how to add scrap along the bottom of a built out baseboard in order to give something for the baseboards to nall in to.
The floating trim in this case is 1/4″ thick. I’ve used 1/4″ thick scrap where I can along the bottom for the baseboard to attach to.

Prepping your room for efficient baseboards installation

Adding scraps, like the picture above, is necessary when you are building out the trim or have floating trim that the baseboards will attach on. If I only nail to the top floating trim, the bottom baseboard would not be secure and would shift around because of the lack of backing.

Even if there was a wall behind the floating trim, there would still be a 1/4″ gap between the final baseboard and the wall because of the 1/4″ thickness from the floating trim. I always add scrap along the bottom of the wall for support and as nailers for my baseboards.

Label the backs of your boards

You might think this isn’t necessary, but in a square or rectangular room there are going to be some pretty close measurements. By writing the measurement on the back of the board you are taking the guess work out of which board goes where.

Plus, if you always measure your rooms counter clockwise (or clockwise for you lefties) you will never lose track of where the boards will end up.

Once I have all of my baseboards cut I place them next to the wall where they will be installed.

Labeling the backs of the boards makes it easy to recognize which board goes where when you're adding baseboard to a room. When installing outside corners, titebond glue prevents separation of the joint later.
Adding wood glue on your outside corners will prevent future separation

Installing Baseboards on Outside Corners: Use glue and tape

By gluing and adding blue painters tape I can avoid nailing small pieces of trim that might split. It also allows me to create a perfect 90 degree angle on a corner that isn’t perfectly 90 degrees.

I use this method on bullnose corners too.

blue painters tape wraps around two outside baseboard corner assemblies holding them together while the glue sets up for installation.
I let this assembly sit for ten minutes before attaching to the wall. I left the tape on for another hour while the glue dried.

Installing Baseboards in a Corner? Use a Screw

Once you test fit your baseboards you will see what adjustments you need to make for a better fit. Either trim the boards or scribe if necessary. For corners that sink in from an uneven drywall finishing at the floor, use a flat head screw – 1 1/4″ is usually what I grab, and drill it into the base of the corner.

The corner below is a coped corner. A coped angle can adjust for a corner that isn’t perfectly 90 degrees, but it can’t fix a corner that is sunken in. That’s where the screw trick comes in handy

A small gap is shown at the base of two intersecting pieces of baseboard because the wall sinks in or sucks in at the base where the floor meets the wall.
If you look closely you can see that the right, bottom side of the baseboard is sunken in, away from the top and left baseboard.

By adding a screw behind the baseboard, I can push the bottom of the baseboard out.

drilling a screw into the wall at the base where the floor meets the wall gives a nice backing or shim to push the board out away from the wall.
I am placing the screw into a scrap piece of backing I used to build my trim out because this wall had wainscoting applied

I can then adjust the screw in or out to correct the gap between the baseboards

Final baseboard installation after the screw was used to push the baseboard away from the sunken in wall.
See how the gap is gone once I put the baseboard back in place?
Why not shims? Well, shims are really great for crowns where this happens because of how shims taper. But it's not easy to shim a baseboard to correct this gap because the shim would come in from the top and push the top out further from the wall as the shim goes down. 

Basically, it would make it worse. Play around with it, you will see what I mean. If the wall bows out at the base where the floor meets the wall, then grab your shims, but this is rarely the case.

Lastly, nail size does matter

If you are only planning to install directly in to studs then 1 1/2 – 1 3/4″ long nails will work great, depending on the thickness of your baseboards. However, there are occasions when you will need a smaller nail.

Choosing shorter nails

If you only plan to nail in to drywall, you should change your nail out to something that won’t go past the drywall. When you are shooting in to dead space behind a wall you never know if there is a pipe or electrical wire in it. I make it a point to shoot all of my long nails first, then swap my nails out for shorter ones and go back and do those last.

Use an X pattern with two nails crossing over each other to attach trim to the wall that won't go into a stud. This will securely anchor it in to the drywall.

I will also swap my nails to a smaller size when I am nailing shoe molding or another smaller trim on to existing trim or when I am nailing corners together. By using shorter nails you will prevent the boards from splitting.

Calculating nail length

Depth of trim + depth of what you are nailing in to + 1/2″ when going into a stud.

When I know most of my nails will only be going in to drywall, like in the case of panel molding, wainscoting, shiplap or board and batten installation, I will shoot my short nails first, then go back with longer nails where there are studs.

Most baseboards are 3/8 – 5/8″ thick. Drywall is 1/2 – 5/8″ thick (if you aren’t sure how thick yours are, assume they are 1/2″). If your baseboards are 3/8″ thick, you can get away with 1 1/4″ nails when going into studs behind the drywall. Mine are 1/2″ thick and I use 1 3/4″.

When I’m nailing into drywall I don’t use anything longer than the the depth of my trim + 1/2″.

That’s it.

I hope you find my baseboard installation tips useful and add a couple of them to your toolkit.

one room challenge logo for shared girls bathroom

This tutorial is part of the Fall 2022 One Room Challenge. This post is for week two of the eight week challenge. If you would like to read more about the challenge or see the incredible transformations being done by other guest designers, click here. If you need to catch up here’s the link to last week’s post. If you enjoy building stuff for your home, check out my nightstand plans, they’re easy to follow and look amazing when completed.

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