If you have an old staircase railing that needs to be replaced or updated, I’ve made a tutorial on how to build and install custom DIY stair railing for your house.

Depending on the type and size of your house, your stair configuration might be different than what’s in this tutorial, but the concept of building the stair railing would be the same. You could easily modify these plans to your needs and your stair configuration.

In this tutorial, I will be explaining how to install stair rails for a house with two stair sections. The first horizontal section is located above the stairs, and the second section starts with a horizontal panel and then slopes down with the stairs.

You also might be interested in my other living room projects such as DIY Plantation Shutters and Reclaimed Wood Frame Sign.

Custom Stair Railing PDF

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This PDF download includes Cut Diagrams, a List of Supplies, and 3D illustrations with detailed steps to build the project. Measurements are in imperial and not metric. Does NOT include SketchUp/CAD files.

Custom Stair Railing

This PDF is free of charge, but if you are feeling generous today, you could give a small tip to help me create more projects. Thank you!

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Note: Lumber dimensions are listed as nominal size.  See lumber sizes for actual dimensions vs nominal.

Disclosure: Some of the links on this page as well as links in “tools for this project” and “material list” sections are affiliate links.

Dimensions

Cut List

Step 1 – Cut Posts for the Stair Rails    

When designing and building the stair rails, first you’ll need to figure out where to place the posts. The posts need to be firmly attached to stairs or the wall to support the weight of the rail panels. 

For this project, I’m using 4×4 poplar wood posts that are typically used for stairs. The actual width and depth of the 4×4 post is 3 1/4″ x 3 1/4″. This is different than if you were to use a regular 4×4 pine construction lumber which is 3 1/2″ x 3 1/2″. 

Take the 4×4 poplar posts and cut three pieces to 38″ in length. Then cut one piece to 42″ and one piece to 52″ in length. Take one of the 38″ pieces and rip it in half with a table saw. This half-cut post will be used at the rail segment that attaches to the wall. 

Once all the posts are cut, use a Kreg Jig to drill pocket holes at the bottom of the 38″ post and a 42″ post. The Kreg Jig needs to be set for 2 ½” pocket hole screws. No need to have pocket holes in the half-cut posts or the 52″ post.  

Step 2 – Measure and Cut Base Moulding for the Posts

The lower end of each post will have a base moulding around it to make it look prettier and to cover the pocket holes. These moulding boards are typically made from MDF boards, just like crown mouldings and baseboards. You could purchase these boards already painted white. 

Take 1×4 and 1×6 MDF boards and cut the base moulding pieces as shown in the cut list. These moulding boards will be attached to the post later after everything is painted. 

Step 3 – Cut Handrails and Base Rails for Horizontal Section

For the base rails and handrails, I used 2×4 redwood that was ripped to 2 ½” in width. The 2×4 by itself was too wide for the handrails so trimming it to 2 ½” in width looked much better.  

Take 2×4 redwood and cut two pieces to 56 3/4″ in length and one piece to 36 1/4″ in length for the top handrails of the horizontal section. Then using the table saw, rip these boards to 2 1/2″ in width. 

The base rails will be slightly shorter because of the base moulding around the posts. For the base rails, cut two pieces to 55 1/4″ and one piece to 34 3/4″ in length, then rip them to 2 ½” in width. 

Next, take 1 ½” wide by ¼” thick board and cut two pieces to 56 3/4″ in length and the other piece to 36 1/4″ in length. This ¼” thick board will be placed at the top of the rail panel with balusters attached to this board. Then the handrail will be placed over this ¼” board and nailed from the bottom. 

Using a Kreg Jig, drill pocket holes on the end of each base rails and handrails. The Kreg Jig should be set for 2 1/2″ pocket holes. 

Step 4 – Measure and Cut Handrails for the Sloping Section

The sloping section of the rail needs to be cut at an angle on both ends. This angle may vary depending on the slope of your stairs but for this project, the angle is 42 degrees. 

Similar to step 3, take 2×4 redwood and cut the base rail to 104 1/8″ with 42 degrees miter cut on both ends. Next, cut the handrail and 1/4″ thick board to 106 1/8″ in length with a 42-degree cut. Then rip both of these 2×4 boards to 2 1/2″ wide and drill pocket holes on both ends of the handrail.

Step 5 – Cut Balusters for the Horizontal Section

When cutting balusters, it’s important to make them all exactly the same length. Use a stop block on your miter saw to ensure the lengths are perfect. 

Take 1×2 poplar wood boards and cut 39 baluster pieces to 29 3/4″ in length. These pieces will be used for the horizontal section of the stair rails.

Step 6 – Cut Balusters for the Sloped Section

Similar to step 5, the balusters for the slopped section also need to be perfect lengths so use a stop block on your miter saw. 

For the sloped section of the stairs, the balusters need to be cut at a 42-degree angle on both ends. Use the same 1×2 poplar boards and cut 22 balusters at 30 1/2″ in length. 

Step 7 – Make Spacer Jig for Attaching Balusters

When attaching balusters to the upper and lower rails, you want to make sure they are perfectly straight and have the same distance between each other. Having the balusters equally spaced makes the whole project look nice. To do that, you’ll need to make spacers that you could place between balusters to ensure equal distance. 

Since some balusters are spaced 2” apart and some 4”, you need to have two spacers for the horizontal sections and two spacers for the sloped sections. 

Take 3/4″ plywood or any scrap wood and cut one piece to 2 3/4” x 2 ½” and another piece to 4 3/4” x 2 ½”. Then cut out a notch with a jig saw that is ¾” x 1 ½” on both pieces. See picture. These spacers will be used for the horizontal section of the rails. 

Now, the spacers for the sloped section need to be cut at a 42-degree angle on both sides. To simplify things, the ¾” x 1 ½” notches are not required for these spacers, although you could make them if you want. Cut one spacer to 5 1/4” and another spacer to 2 5/8” with a 42-degree angle on both sides. 

Step 8 – Round the Corners of Bottom and Top Rails

Since the bottom and handrails were ripped to a shorter width, the ripped side will have sharp corners and the non-ripped side has rounded corners. To make them all the same, take a wood router and go thru the sharp corners with a round-over router bit. This will make all the corners rounded. 

Step 9 – Attach Balusters to the Bottom Rail of the Horizontal Section

Find the center of the bottom rail and make a small pencil mark. This will be the location of the first baluster. Apply wood glue at the bottom end of the baluster, then place it at the center mark and nail it with a 2” brad nails. Now place a 2” spacer against the first installed baluster, then insert the next baluster into the notch and attach with brad nails. Repeat the process for the remaining baluster using the spacers. 

The balusters need to be attached in pairs of 3 that are 2” apart. Then there will be a 4” space between the next pair of three. Finish attached remaining balusters to the bottom rail with wood glue and brad nails. 

Step 10 – Glue and Attach ¼” Thick Wood Strip on Top of Balusters

The main purpose of the ¼” thick wood strip at the top of the rail is to hide the nails. If you do not have this piece, you will need to attach balusters directly to the handrail with nails from the top, which will make the nails exposed. These nails could be covered with wood filler, but that is a lot of work and it may still leave a small nail mark. So instead of nailing the top handrail to balusters, you’ll need to attach a ¼” thick wood strip first. Then the top handrail will be nailed to the strip from the bottom to hide the nails.

Attaching the ¼” thick wood strip is very similar to the bottom rail. Again, find and mark the center of the strip and then attach to balusters with wood glue and 1” brad nails. Use the same spacers to make sure that the balusters are straight. 

Step 11 – Assemble the Sloped Rail Section

Attaching the sloped rail section is very similar to the horizontal section. First, find and mark the center of the bottom rail. Then instead of attaching a baluster in the center (like we did in the horizontal section), we’re going to have a 5 1/4 spacer centered on the mark. Next, attach the baluster on each side of the spacer. Continue attaching the remaining bluster across the bottom rail. Finally, attach the 1/4″ thick wood strip and then top handrail. 

Step 12 – Paint all the Pieces 

Now that you have all of the pieces cut and rail panels assembled, it’s time to paint. Use a paint sprayer to have the paint equally applied. You might need to spray several layers to make it look good.

Step 13 – Install Half-Post to the Wall

It’s time to install the rails. Starting from the wall, first, attach the half-post to the wall with 4″ wood screws. The 4” screw needs to be attached to the stud in the wall, otherwise the rail will become loose over time. 

Check to make sure that the post is leveled. Drive-in two screws at the bottom of the post below the 18″ mark because the base moulding is 18” tall and will cover the screws. Then drive-in the third screw at 35″ from the bottom. When the stair rail is installed, this screw will end up behind the handrail. We want to cover up the screws or nails as much as possible. 

Step 14 – Wrap and Nail the Base Moulding Around the Post

Now that the first post is firmly secured to the wall, attach the base moulding at the bottom of the post with 1 1/4″ brad nails. See picture. 

Step 15 – Secure Rail Panel to the Post

Take the first horizontal panel and attach it to the post with 2 1/2″ pocket hole screws at the bottom rail. The rail panels need to be attached 3″ from the bottom of the post. You could use 3″ tall blocks to set the panel on, for easier installation. 

Place a handrail on top of the 1/4″ thick wood and attach it with 1″ brad nails. Then use 2 1/2″ pocket hole screw to attach the handrail to the post. 

Step 16 – Install the Remaining Posts and Rail Panels

Take the next 38″ post and attach base moulding pieces on two sides that don’t have pocket holes. Next place this post against the first panel and attach it to the pony wall with 2 1/2″ pocket hole screws. Then drive-in the pocket holes into the top and bottom rail to secure the panel to the post. Cover up the post pocket holes with base moulding. 

Repeat the process to install the next set of rail panels and posts. The panel that is sloping down will not be raised 3″ up. 

Step 17 – Cover up the Pocket Hole

To cover up the pocket holes in the handrails and bottom rails, take a 3/8″ wooden dowel rod and cut it into small sections of about 2″ in length. Then hammer the dowel piece into the pocket hole. Using a dovetail saw, cut off the remaining dowel that is sticking out. Sand the rod and make it even with the rail. Then touch up with the paint to cover the wood. You are done with the custom DIY Stair Railing.