Unevenly spaced balusters look amateur and detract from your porch or deck’s overall appearance. Proper spacing is also important for safety. Building codes typically require balusters to be spaced no more than 4 inches apart to prevent small children from slipping through or getting stuck in between them.
In the video above, general contractor Tom Silva shows This Old House host Kevin O’Connor a quick, cheap, and accurate way to space balusters yourself. This simple trick involves an elastic band, a tape measure, and some careful alignment for even placement—no fractions involved.
The Elastic Band Method for Spacing Balusters
Silva’s innovative approach eliminates the need for complex math and ensures consistent spacing throughout the railing. To use this method, you’ll need the following materials:
- Elastic band (approximately 60 inches long)
- Permanent marker
- Tape measure or ruler
- Scrap piece of baluster
- Weight (such as a coffee mug or book)
Preparing the Elastic Band
Lay the elastic band flat on a work surface. Place weights on each end to keep it straight without stretching. Using a tape measure and permanent marker, mark the band every 4 inches along its length.
Using the Band for Spacing
Place a scrap baluster flush with the inside edge of one post. Stretch the elastic band from one post to the other, aligning a mark with the inside edge of the far post. Adjust the band so that a mark aligns with the outside edge of the scrap baluster. Place balusters along each mark on the stretched band.
This method ensures the spacing between balusters remains consistent, even if the total distance between posts isn’t perfectly divisible by 4 inches.
Why This Works: The elastic band method accounts for both the spacing and the thickness of each baluster — something that trips up even experienced builders doing the math by hand. As demonstrated on This Old House, you first clamp a scrap baluster flush with the inside edge of one post, then hammer a brad through the first mark on the elastic tape into the baluster’s center. Stretch the tape to the opposite end, keeping the spacing between marks to 4 inches or less for safety. When you’re satisfied with the spacing, nail through a second mark at the other end, then transfer the marks from the elastic tape to the rail.
Tips for Accurate Baluster Placement
While the elastic band method is pretty simple, there are additional considerations to ensure accurate placement.
Accounting for Baluster Thickness
When using the elastic band method, account for the thickness of the balusters. Place each baluster on the sides of the elastic band marks, consistently in the same orientation as the scrap baluster against the post. This ensures that the space between balusters remains code-compliant.
Maintaining Consistency at Post Ends
For a professional look, the space between the end balusters and the posts should be equal on both ends of the railing. The elastic band method naturally achieves this balance, as demonstrated in the video.
Marking Baluster Positions
Once you’ve determined the correct positions using the elastic band, mark these spots on the railing. This step allows you to remove the elastic band and have clear reference points for installing the balusters.
Alternative Methods for Spacing Balusters
The elastic band method is efficient and accurate, but there are other approaches to spacing balusters that may be suitable for different situations.
Using a Spacer Block
Create a wooden spacer block cut to the exact width you want between balusters. Use this block to position each baluster as you install them. While this method is accurate, it may be more time-consuming than the elastic band approach.
Measuring and Marking
For shorter railings, you might opt to measure and mark each baluster position individually. This method requires careful calculation to ensure even spacing and equal end spaces.
Center-to-Center Method for Stairs
When spacing balusters on a staircase, Tom Silva uses a center-to-center measurement approach. He measures from the left side of one baluster to the left side of the next to get the center-to-center distance, then rounds to an easy number to work with. For example, if the measurement comes out to four and five-eighths, he rounds to five inches for simpler layout. From there, he clamps a baluster to the edge of the bottom post, keeping it flush on the inside, and works from that reference point.
Prefabricated Railing Systems
Some manufacturers offer prefabricated railing systems with predrilled holes or baluster slots. This simplifies installation but offers less design flexibility.
Baluster Layout Tool
Specialized baluster layout tools are also an option. These tools generally consist of adjustable arms that can be set to the desired spacing. Once configured, you can place each arm where a baluster should go.
Common Mistakes To Avoid When Spacing Balusters
When spacing balusters, be aware of these common pitfalls:
- Failing to account for post and baluster thickness when measuring
- Inconsistent spacing at the ends of the railing
- Neglecting to check local building codes for specific requirements
- Misaligning marks on the elastic band due to stretching or other mishandling
Additional Safety and Design Considerations for Balusters
Proper spacing isn’t the only thing to think about when designing your balusters. We’ll discuss materials, maintenance, and more below.
Material Compatibility
Ensure that your balusters, posts, and rails are made of compatible materials. This prevents issues such as expansion, contraction, and durability. For example, mixing metal and wood may require additional precautions to avoid corrosion or wood deterioration over time.
Baluster Height
Confirm that your balusters meet height requirements as specified by building codes. The standard railing height typically falls within the safe but convenient range. Short balusters may pose a safety risk.
Securing Balusters
The way you attach the balusters to the rail affects the system’s overall stability. Whether you use screws, nails, or brackets, ensure each baluster is securely attached. Loose balusters can compromise the railing’s safety and effectiveness.
Coordinating With Railing Design
Balusters should complement the railing’s design and your home’s architecture. For instance, slender metal balusters might look best in contemporary settings, while wider wooden balusters suit traditional designs.
Color Coordination
Choose colors that match or contrast well with your existing structures. Try matching the baluster color to the trim of your house or using a contrasting color to make the railing a focal point.
Maintenance and Upkeep
At the very least, you’ll have to dust and clean the balusters to keep them looking fresh. Materials such as metal and synthetic wood are low-maintenance options, while traditional wood may require regular painting or staining.
Advanced Techniques for Baluster Installation
For those experienced in home improvement or professional contractors, advanced techniques can further improve your baluster installation’s precision and durability.
Using Jigs for Consistency
A jig is a custom-made tool that helps replicate the exact measurement and positioning of each baluster, ensuring consistency across the entire railing. While creating and using a jig requires extra time initially, it can save time and reduce errors in the long run.
Jig Technique in Detail: On a This Old House project, the team built a jig specifically to hold each baluster square and vertical relative to the drill, ensuring a clean, straight hole every time. A piece of tape wrapped around the drill bit marked the target depth — exactly half the length of the dowel — so each hole was consistent. Once both halves were drilled, a dowel was glued and inserted to join the pieces. As the carpenter noted after tapping the joint together and seeing glue squeeze out: “Once that dries it’s never gonna break right there. Not for 130 years.”
Laser Levels for Precision
Laser levels can offer higher precision than traditional levels or measuring tapes. Use a laser level to ensure each baluster is perfectly vertical and the rail is entirely level throughout its length.
Advanced Fastening Techniques
Using advanced fastening techniques, such as pocket screws or dowel joinery, adds strength and durability to the railing. These techniques often provide a cleaner look and hold the construction longer than basic nails or screws would.
Nailing Strip Method: Rather than toenailing into the side of each baluster — which leaves visible holes that need filling — a technique used on This Old House projects involves attaching balusters to a thin strip of wood first, screwing through the strip and into the baluster. This hidden-fastener approach produces a cleaner finished look and simplifies assembly. It’s also important to seal all pieces of the railing system before assembly, coating all six sides — especially the end grain and the underside of the nailing strip — to protect against moisture damage.
