Tips for Installing Balusters

Most people reading this have never done this before and that’s why they’re reading this.  I was in the same boat when I did this in 2021. Below are questions I had and had to dig up from various sites.

1.                   How far apart can my balusters be?

First, always check your local codes to see what inspectors are looking for. The last thing you want to do is drill a bunch of holes in your treads that are the wrong distance apart. The most common maximum distance I’ve seen and read is 4”, meaning the space between balusters cannot be more than 4”. That code is similar in my location, however, I made the distance smaller in order to meet that requirement while ensuring the same measurement and number of balusters on each stair tread.  If I followed 4” exactly then the number and location of the holes on each step would vary.

2.                   How do I drill holes consistently on each step without measuring every step?

Make a template. Assuming you have open ended treads, the easiest thing you can do it take the top of a shoe box and cut it so it’s about 9” long and then cut the lip off of one side. This way you can put it onto the corner of the step. Once you figure out your measurement you can drill holes on the template so you can mark your steps.

3.                   How do I know how to space the balusters?

There might be some trial and error based on your measurement so DON’T DRILL until you’ve tested the spacing on several steps, especially the top and bottom where you tie into the newel post.

I figured out my spacing on my balusters before I installed the newel posts so that I could adjust their position and therefore the last gap. In my case, I was using thinner metal busters so only installing 2 on each step would not be an option to keep the gap under 4”. Therefore I knew I needed 3 per step. Measure the depth of the stair tread from the riser to the next riser. By this I mean don’t include the rounded edge on the front of the step; that’s just an overhang that doesn’t need to be factored for this. Once you know exactly how deep the step is and you know you need 3 per step, find the middle of the tread. That is your middle baluster. From here you are going to take the measurement from that middle baluster to the riser and multiple time 2/3. This will be how far the next baluster will be on either side of the center. I know you’re thinking “but there’s a smaller gap on from the last baluster to the riser than from the other 2 balusters”.  You are correct. It is 1/3 of the distance. However, remember the next step above is going to have a similar 1/3 gap which means the 1/3+1/3 on both steps equals the 2/3 gap that you were just worried about.  The gap is now equal.  For example, the tread is 9” deep from riser to riser (which excludes the rounded edge) and the middle is 4 ½”. Multiple 4.5 by 2/3 equals 3”, which means the next balusters (on both sides) are 3” away from the center mark. The remainder is 1 ½” away from the riser. The next step is also going to have a 1 ½” space. That 1 ½ from one tread plus the 1 ½” on the next tread gives a space of 3”, which is equal to the baluster spaces on the each step.

4.                   How do I secure a baluster?

The balusters can be secured using a small screw through the top into the railing.  If you are using a metal baluster there should be a hole predrilled that can be used.  If it is wood then you’ll need to drill a pilot hole. On the step where you drilled a small hole for the baluster to rest inside, you should put 2-parts epoxy glue in (be sure to stir it). This will secure the baluster at the top and bottom making it very sturdy.