As promised, I am putting forward information on the installation of iron balusters, including wrought iron balusters and wooden balusters. During the day, one of the most common questions I get from customers is the “how” behind baluster installation.
Many building codes require three balusters on a tread to comply with the 4" sphere rule. Check with your local code officials if you have any doubts about your stair's compliance.
Preparing Your Work Area
First, I let the customer know that the very last thing in balustrade installation is the iron balusters. It simply works well to install the newel posts, handrail, treads and risers first. Once installed, lay out the balusters on the floor and use a level to plumb up to the handrail center and mark the connection at the center bottom of the handrail.
Using a ½ inch paddle or spade bit, one can drill upward 1 inch deep into the handrail. Using a 5/8 inch paddle bit, drill a hole no more than ¼ inch deep into the floor. Once these are drilled out, the bottom of the handrail can be sanded with an orbital sander and the complete balustrade system can be stained and finished. Once the stain and finish are complete, one can begin installing the iron balusters.
Cutting the Balusters
One of the following two tools is recommended for cutting metal or wrought iron balusters: a power miter box with a metal cutting blade, or a portable band saw. My preference is the portable band saw. This also works for cutting wood balusters. It works cleaner, is more portable, and doesn't cause sparking as does the power miter box (or chop saw).
Turn the baluster upside down and set the round dowel top into the hole in the floor. Slide it into the hole in the floor while holding the baluster plumb to the hole under the handrail. Mark the baluster with a pencil, measure up 3/8 inch minimum and that would be the cut mark. Note that you are cutting off the bottom, not the top, of the baluster. This ensures proper alignment of the design elements.
Installing the Balusters
For gluing, the installer has two options: Epoxy or construction adhesive. My personal preference is construction adhesive as I have more control over the product and, if it gets messy, wipes away easily and can also serve as a caulk around the iron. Epoxy comes in the mixing tubes and doesn't always mix properly. If it gets messy and dried, removing the epoxy also removes the powder coating on the iron. Some carpenters prefer and have their own control over epoxy. I do not. I find construction adhesives easier to work with.
Squeeze a small amount of the adhesive into the hole under the handrail. The adhesive is thick and slow and will not drain back out, giving time to complete the installation. Make sure the shoe for the iron baluster is slid up while installing. Slide the baluster’s round dowel up into the ½ inch hole under the handrail and then drop it into the 5/8 inch hole in the floor in a bed of additional construction adhesive. Square off the baluster's alignment then drop the baluster shoe down to the floor. If the baluster shoe comes with a set screw, use an Allen wrench to tighten it. The glue in the handrail hole will settle around the baluster creating a perfect seal. Once the glue has dried the baluster will be well secured, even helping to strengthen the handrails load.
When installing 5/8 inch wrought iron balusters, the process is identical, one only needs to drill a 5/8 inch hole under the handrail and a ¾ inch hole at the floor. 5/8 inch iron is ideal in remodeling work, when replacing wood balusters. Most installed wood balusters have a 5/8 inch hole under the handrail and a ¾ inch hole at the floor. If replacing wood balusters with ½ inch iron, it is usually recommended to install a baluster shoe under the handrail to cover a small square peg in a larger round hole. The use of wood or cabinet screws helps to lock the baluster in, serving as both a wedge and forcing the baluster on center.
Round 5/8 inch iron or metal balusters can be installed without base shoes simply by drilling a 5/8 inch hole into the handrail and into the floor and following the same procedure outlined above.
I have been asked about making the holes square. It is possible with a little more work. To cut the square hole in the floor or handrail, drill a round hole in the wood the same size at the baluster's overall width. Then chisel out the hole to make it square. With tubular steel balusters, you can take an offcut piece, hammer it over the hole which gives an indentation on all four sides, making it easier to chisel out. Another option is a "mortising bit." I have not used one of these but have spoken with carpenters who have. Their comment tends to be that this method is a "pain in the you know what."
Joseph Swallow has been with Westfire Manufacturing since 1994 and now serves as the company's CEO. Prior to Westfire, Swallow worked in Southern California and Las Vegas as the primary sales representative for Hardwood Creations, a company which he had founded in his garage in 1981. Westfire Stair Parts, including wood balusters and wrought iron balusters, are available anywhere in North America and can be purchased by calling Westfire toll free 1.800.692.6996.