How to Install DIY Stair Wainscoting the Easy Way

We have lift off in the foyer/stairway/hallway makeover!

For years, I’ve envisioned pretty molding below the existing chair rail on our stairs. But geometry wasn’t exactly my strength in high school, so I avoided it. However, it’s not nearly as complicated as I thought it would be!

DIY wainscoting on staircase

Why We Chose Picture Frame Molding for Stair Wainscoting

Robert and I chose picture frame molding for this wainscoting project because it is definitely one of the easiest methods for adding dimension without a lot of complication. (Plus, it’s perfect for our traditional style colonial house. We have picture frame molding in multiple rooms of our house at this point.)

Here are 8 DIY wall molding ideas, if you want other ways to add character to you walls if this more traditional style isn’t really your jam.

Types of Molding for Wainscoting

You could adapt board and batten or panel molding to continue up your stairs too, if that is the look you prefer.

After some other carpentry projects happen in this space, we plan to paint the trim a contrasting color from the walls.

But I thought it would be helpful to go ahead and share our process in case you ever want the tutorial broken down for you to use.

DIY wainscoting on stairs

Supplies Needed

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Tool Alternatives

If you don’t own a miter saw or brad nailer, you can rent one from Home Depot, Lowe’s, or Sunbelt Rentals. You can use a miter box and hand saw instead of a miter saw, but it will come with some trial and error.

Related: The Best DIY Tools for Beginners

How to Install Picture Frame Wainscoting on Stairs

Step 1 – Install the Chair Rail

(Our chair rail was already on the wall when we moved in, but here is how we have installed chair rails in other rooms.) Mark 36″ from the tread (the floor) onto your wall to set the height of where you want your chair rail to be.

Following the angle of your baseboard, mark a pencil line all the way up the stairs at the 36″ height.

Using a miter saw, cut the first chair rail piece at a straight cut to the width of your wall. Position the chair rail onto the angled pencil line you previously marked on the wall, and pressed the chair rail in place.

Press the brad nailer at an angle in alternating directions as you attach the chair rail to keep it flush to the wall (this will allow you to remove the chair rail one day without much damage to your drywall if your style ever changes).

Nail the chair rail piece to the wall with the brad nailer. For the next chair rail piece adjoining the one you first hung, cut the chair rail piece to the width of the next wall at a 45 degree angle.

Then, using a coping saw, carve out the profile of the 45 degree cut on the chair rail to make it fit snug to the design on the already hung chair rail piece.

pencil markings on stairs for molding

Step 2 – Mark the Box Molding

Plan how wide you want each picture frame box to be below your chair rail. Then, use a level to mark one side of the box on the wall so it’s plumb (straight up and down).

Repeat on the other side of the box to the width you prefer.

Using a 2×4 board as a spacer, press the board against the chair rail and mark the edge of the spacer connecting the 2 vertical pencil marks you made.

Use the 2×4 board again to repeat for marking the bottom of the box by pressing the board against the baseboard (called the wall stringer).

Repeat these steps to mark more boxes on the wall to place your molding later.

using a protractor to find molding angles

Step 3 – Calculate Molding Cuts for Angles

From the molding frame lines you made with your spacer and level, use your protractor to find the exact angle of your molding corners.

Obtuse Angles

Take your obtuse angle measurement (the largest angle) & divide by 2 then subtract that result from 90 degrees. This will give you your obtuse angle cut.

In our case, our calculations looked like this: 130 / 2 = 65 then 90 – 65 = 25 | So our cut setting on the miter saw platform was set to the standard 25 degrees.

Acute Angles

Next, find your acute angle measurement (the smallest angle) using the protractor.

Take your acute angle measurement and subtract it from 180 degrees. Then, divide that number by 2 to give you your cutting angle.

In our case, our calculations looked like this: 180 – 50 = 130 then 130 / 2 = 65 | So our cut setting on the miter saw platform was set to 65 degrees.

making pencil marks on wall for adding angled molding on stairs

Step 4 – Make a Saw Guide

The tricky part about our miter saw is not every angle can be cut without some sort of guide. So we made one to get our cuts exact.

Making a guide will allow you to change the starting angle at the 0 setting on your miter saw from 90 degrees to 45 degrees.

DIY wainscoting using miter saw guide

To make the guide, take a 1×6 board and cut it into a 10”x6” 90 degree triangle.

  1. Mark 10” on the 1×6 board, and then cut at that mark at a 45 degree setting on your miter saw.
  2. Repeat this step for both sides of the saw platform.
  3. Next, cut a 1×2 board at 10”.
  4. Screw the 10″ 1×2 board to the 10″ side of the triangle.
  5. Place the 10” side of the triangular guide on the miter saw platform with the 2” portion sticking up. Clamp the two triangular guides to the back of the miter saw platform (see photo below).

This will create the guide you need to make accurate angle cuts. The tips of the triangular guide should not cross under the saw blade, so be sure to leave a gap for the saw blade to pass during cuts.

Step 5 – Cut Molding Pieces

Once the triangular guides are in place on the saw, your new 0 setting angle becomes 45 degrees instead of 90 degrees. For determining your setting on the saw, subtract 45 degrees from your cutting acute angle you calculated in Step 3.

DIY angle cutting guide on a miter saw for wainscoting

(In our case, our calculations for our first cut was 20 degrees.)

Robert placed the saw blade to 20 degrees, put the molding into the guide, and cut the molding on each side to create adjoining acute molding pieces. 

cutting angles on trim on a miter saw
cutting angled molding on a miter saw

Next, we cut the obtuse angles. (In our case, our calculations for our this cut was 25 degrees.)

Robert set the miter saw, starting from 0 to 25 degrees and cut each of the pieces. You will end up with the pieces meeting snug to form the obtuse angle you needed. 

angled picture frame molding on stairs

Step 6 – Nail Up Molding

Attach your newly cut picture frame molding to the wall using the brad nailer.

Place the nailer at an angle in alternating directions as you attach the molding to keep it flush to the wall (this will allow you to remove the molding one day without much damage to your drywall if your style ever changes).

installing picture frame molding on stairs
nailing molding cut at an angle on stairs

Step 7 – Caulk and Wood Fill

Once all of your molding is nailed to the wall, apply wood filler to the nail holes and caulk to the cracks. (Do not use caulk in nail holes as it can crack overtime and expose the holes.)

After wood filler is fully dry, sand it smooth.

Step 8 – Paint

Finally, apply your paint of choice.

After a few more carpentry projects around here, we will paint this stair wainscoting soon. I still haven’t picked a paint color, but you can bet on the fact it will be a statement-making contrasting trim color.

Related: How to Replace Stair Spindles – DIY Stair Makeover

picture frame molding stair wainscoting

Adding this molding makes such a subtle different on our stairs, but it does make the space feel a bit more upscale. It’s definitely one of my favorite ways to make a house look more expensive.

Envision it one day with a permanent traditional runner rug on those stairs too, but we’re not there quite yet.

Frequently Asked Questions

What type of paint should I use on trim?

The best type of paint for trim is urethane alkyd enamel such as Benjamin Moore Advance because it cures to a harder finish than latex to prevent wear over time.

How high should wainscoting be on stairs?

Place the top of your wainscoting at 2 1/2″ lower than the height of your first floor wainscoting panel. Traditionally, wainscoting should be about 1/3 of the wall’s height.

Does wainscoting increase home value?

Adding wainscoting won’t necessarily increase the value of your home, but it will increase its appeal to home buyers to make it easier to sell.

More DIY Molding Ideas

Here are more DIY wall molding projects we’ve done in the past around our house with tutorials to help you install it yourself.

How to Wallpaper Inside Picture Frame Molding

how to wallpaper inside picture frame molding

How to Quickly Beef Up Crown Molding and Baseboards

white crown molding and black painted walls

DIY-able Wall Molding Ideas to Add Character to Your Home

diy wall molding ideas

You can follow along on our project progress here in our Instagram Stories! We’ll be working away on this staircase, foyer, and hallway for the next several weeks.

Or sign up to our email list to get more peeks at the progress with how-tos…

What do you think so far? Is this something you think you’ll try? Has geometry ever alluded you too? Believe me, we’ve had our fill of our 10th grade math flashback after this project.

If you try this yourself, ask any questions in the comments so I can help.

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4 Comments

  1. Wow! Your wainscoting looks great! Lauren & Robert, you have done such a great job — and what a difference this makes. You two make a wonderful team and everything you do always turns out looking so nice. Also, your instructions are always so easy to follow! Thanks, again, for sharing with us!

    Your home is so beautiful and everything you have done has made it even more beautiful!

    Have a great weekend!

  2. I absolutely LOVE molding, but we have orange peal textured walls and I feel like it might look terrible. Plus our floorboards are basically 2×6’s without much to rest a thin board on-so my hubby says no. If you have any info on how or what to do for that, please share!!