Step 26b – Build the Railing

With the treads in place, it was time to attach the ballusters and railing. The ballusters are made from 2×2’s with small notches routed out of them so they lock in between the treads and ensure each of the treads is the same distance apart. In the center of each notch I drilled two holes, and then used a larger drill bit to bore out just a little wider section at the start of the hole. This is called countersinking and with a little help from some wood plugs, allows you to hide the screws that hold everything together.

Balluster with Notch and Countersink Holes

After screwing the ballusters in place, I used scrap wood and masking tape to attach them all together so they were nice and straight. Next, I stapled a long piece of posterboard to one of the ballusters and stretched it around the stairway so it was over the top of the other ballusters. This will be used to get a good estimate of the proper radius for the handrail. You can’t just use the same radius as the stairway because the radius will be just a little bit longer due to the vertical stretching of the railing. Once I felt like I had a good estimate of the railing radius, I set to work making a form for it.

Scrap Wood and Tape Holding Ballusters Plumb

The railing is constructed of seven thin slats, which will be placed on edge and glued together. It’s important to use a slower drying glue so you have time to push them into the forms before they set in place too much. You want them to be able to slide past each other just a little as they bend into the circular shape.

Treads and Main Ballusters Prepped for Railing Attachment

I built the forms with some scrap plywood cut into a curve for the inside, and then small square blocks for the outside of the forms. The square blocks allow for a little bit of space to manuever the slats into place, and then can be snugged up using little shims. It’s important to take care when calculating the radii for the forms. I estimated the radius using the tops of the ballusters, and I want those ballusters to be centered on the bottom of the railing, so I had to do a little math to get the right radius for the inner forms and the outer forms.

Spiral Railing Forms Ready to Go

The next part was incredibly difficult, and if I had to do it over again I would have used maybe 10 thinner slats instead of the seven thicker ones I used. A few of the slats ended up breaking as I was bending them into place. Fortunately, I was able to just put those ones in the middle and once everything was clamped together tightly the mistake was hardly noticeable.

Laminated Slats Clamped Into Place On Forms

Once the glue had dried, it was time to experience the incredible power of sandpaper. You would never dream that this ugly mish-mash of sticks and glue would ever turn into such a beautiful railing, but with some perseverance and an orbital sander, it somehow did. I swear, I’m not playing any tricks on you! The only thing I did to get the before and after shots you see below was to sand.

Glued Slats Before and After Sanding

The last step was to drill holes in the railing for the screws and then screw it onto the ballusters. I used the same method as with the ballusters to countersink the screws and cover them with wood plugs. The color, unfortunately, didn’t quite match the way I wanted it to. The last step was to attach two intermediate ballusters between each of the main ballusters. The building code dictates that a 4″ diameter sphere must not be able to pass through the space between any of the ballusters.

Spiral Staircase with Railing Attached and Intermediate Ballusters Installed

Advice? Questions? I'd love to hear your feedback or help you out in any way I can!