Attaching balusters to a deck railing is an important part of building a safe and secure deck railing system. Proper baluster installation helps ensure that the railing can withstand force and weight, preventing accidents and injuries. While the process requires care and precision, with the right tools and techniques, DIYers can learn how to attach balusters to deck railings successfully.
What are Balusters?
Balusters, also called spindles, are the vertical supports that run between the top rail and bottom rail of a deck railing. They serve both decorative and functional purposes. In addition to contributing to the style and look of the railing, balusters provide support and infill spacing, preventing people or objects from falling through the gaps in the rails. They transfer force and pressure on the railing down to the structural support posts and frame of the deck.
Balusters are typically made of wood, composite materials, wrought iron, or vinyl. The size and shape can vary, with common options including 2×2, 2×4 lumber, round dowels, square, or decorative turned spindles. Structural codes and building standards provide specifications for baluster sizing, spacing, and installation to ensure deck railings can withstand minimum loads.
How Many Balusters Do You Need?
The number of balusters needed depends on the linear footage of your deck railing. As a general rule of thumb, balusters should be spaced with a maximum of 4 inches between them. To determine how many you need:
- Measure the total linear length of your deck railing around the perimeter.
- Divide this length by 4 to calculate how many 4-inch spaces you need.
- Add 1 to get the total balusters needed for that span.
For example, if you have a 16 ft long railing: 16 ft divided by 4 inches equals 48 spaces. Plus 1 baluster equals 49 balusters needed.
Remember to account for all sides of the deck perimeter that have railings. Having some extra balusters on hand is also smart in case any break or are damaged during installation.
How Far Apart Should Balusters Be Spaced?
Proper baluster spacing is critical for safety. Building codes generally require a maximum spacing of 4 inches between balusters infill. This prevents children from squeezing through and adults from falling through. At the same time, you don’t want balusters spaced too tightly or the railing can seem crowded and obstruct views.
Some general guidelines for baluster spacing include:
- No more than 4 inches clear space between balusters
- Bottom balusters no more than 2 inches above the deck surface
- Top balusters no more than 4 inches below top rail
The 4 inch infill spacing is applicable for residential decks. For commercial applications, a tighter 3 inch spacing may be required. To help get uniform 4 inch spacing, use a baluster spacing jig or carefully measure and mark railing posts.
How to Attach Balusters
There are several techniques for attaching balusters depending on the type of railing system:
Attaching to Wood Railings
For simple DIY wood railings, balusters are typically attached using nails, screws, glue, or a combination of these:
- Nailing: Galvanized or stainless steel nails are driven through the baluster into the top and bottom rails. Two 3-4” nails per joint are ideal. Pre-drilling pilot holes prevents splitting.
- Screwing: Stainless steel screws provide extra holding strength. Drive 2-3” deck screws through pilot holes drilled at angles through the balusters into the rails.
- Gluing: Exterior wood glue helps create a stronger bond when balusters are nailed or screwed in place. Apply waterproof adhesive before driving fasteners.
- Nail and glue: For the strongest attachment, use both nails or screws combined with wood glue to attach balusters.
Be sure balusters are plumb and aligned properly before driving fasteners. Clamps and squares can help hold them in position when attaching.
Attaching to Composite Railings
With composite decking railing kits, balusters slide into pre-routed channels or holes in the top and bottom rails. Different composite brands have their own designs. Common options include:
- Hidden fasteners: Balusters fit and lock into internal connectors inside the rails.
- Screw-in brackets: Separate brackets screw to the undersides of the rails to hold balusters in place.
- Adhesive: Some composites rely on exterior-rated adhesives applied during assembly to attach balusters.
Follow the specific manufacturer instructions for composite railings. Using their recommended screws, brackets, or glues ensures balusters attach properly.
Attaching to Cable Railings
For cable railing systems, balusters typically have holes drilled through them so that cables can pass through. To install:
- Cut balusters to length and drill holes if needed before mounting rails.
- Space and temporarily brace balusters along the top and bottom rails.
- Thread the cable through the baluster holes and attach to rail posts with cable hardware.
- Tighten and tension cables to hold balusters firmly in place.
The right cable tension is important – too loose and balusters won’t be stable, too tight and components can bend or distort.
Attaching to Metal Railings
With wrought iron or aluminum railings, balusters typically have decorative shapes and finials that fit into openings in the top and bottom rails. Common attachment methods include:
- Welding: Balusters are permanently fused to the rails through welds.
- Rivets or screws: Mechanical fasteners join the balusters to metal holes or channels.
- Threading: Balusters screw or twist-lock into threaded fittings in the rails.
Proper assembly techniques are needed to prevent metal railings from loosening over time. Have welds, rivets, or screws applied by experienced installers.
Tips for Attaching Balusters
Follow these tips for proper installation and long-lasting balusters:
- Check building codes for required baluster size, spacing, and installation.
- Choose baluster material suitable for outdoor use and exposure.
- Use weather-resistant nails, screws, glue, and other fasteners.
- Pre-drill holes for nails or screws to prevent splitting wood.
- Use jigs and clamps to ensure even baluster spacing.
- Work section-by-section for easiest alignment.
- Attach both top and bottom connections for stability.
- Maintain minimal spacing between balusters.
Taking the time to properly attach balusters is worth the effort for increased deck safety and better aesthetics. Following building codes and manufacturers’ recommendations can help ensure your railing is structurally sound.
Conclusion
Attaching balusters is an essential step in creating secure, attractive deck railings. While baluster materials and railing systems differ, the methods involve securing vertical infill between top and bottom rails. Using proper fastener types, baluster spacing, and installation techniques makes the process easier and produces safer, long-lasting railings. Pre-planning, the right tools, and care when attaching balusters can turn this challenging DIY project into a gratifying accomplishment.