In order to comply with building regulations and codes, balusters must be spaced no more than 4 inches apart on center. The general rule is that your railing must have three balusters per foot (every 12 inches), although you can place them closer together if you'd like.

How long should balusters be?

Guards, spindles, or balusters must be 34” to 38” when measured from the nose of a 10-inch deep tread. Interior stairwells require that anything over 2 steps or 3 risers would need a rail. Balusters, or other options of vertical guards that support a handrail, should be able to support 50lbs over a 1-square-foot area.

How do you measure for balusters?

Measure the length of the space between the end supports of the balustrade. For this example, assume it's 13 feet 5 ½ inches, or 161 ½ inches. Divide that length by four to determine the number of spaces you will need while having a minimum of 4 inches distance between balusters.