How to Install Deck Stair Railings
Guardrails must be provided on the open side of a stair where it is more than 30" above the floor or grade. Stair rails must be at least 34" high, measured from the nosing of the stair treads. No opening shall allow a 4 3/8" sphere to pass through with the exception that you are allowed a larger opening provided for the triangle formed between the stair riser, stair tread and bottom edge of the bottom rail. This open space may not allow a 6” sphere to pass through it.
Be sure to lay out the position of your rail posts before installation. This is usually the trickiest part. If the top rail post is set at the rear of the tread, you will want to align the bottom post similarly. Landings and stairs that change directions will often require the thoughtful situating of rail posts to allow for a system that looks and performs well. Grippable handrails are required and must meet specific requirements.
Guard rails are required on the sides of stairs with a total rise of more than 30" above the floor or grade below.
Secure bottom stair rail post to stair framing with (2) 1/2" bolts or equivalent. In this case, we bolted the rail post to the riser board. You may also attach the post to the stair stringer. Make sure the rail post is long enough for a 34" minimum rail plus additional room for post cap mounting.
Verify that both your top and bottom stair rail posts are plumb. Lay the bottom rail on top of the stairs to determine the correct angle. Mark the intersection of the rail posts with the bottom rail. Cut your top and bottom rails to the same length.
Attach the rail connector to the ends of the top and bottom rail with screws.
Install the bottom rail centered between posts. Install your stair baluster connectors so that each baluster will have less than a 4" opening between balusters.
Align the top and bottom rail sections to mark the corresponding connector locations with a level.
Guardrails on stairs must be at least 34" high, measured from the nosing of the treads. Measure and cut your aluminum balusters to fit your stair railing assembly. Next, slide the balusters over the bottom stair rail connectors. Then, slide the top rail connectors into the balusters from the bottom up.
Notice that the top cap terminates into the rail post at the same height as the deck guardrail. Install the 2x4 or 2x6 rail cap over the top rail. Pre-drill and screw the ends of the top cap into the rail posts and secure the center with additional screws. Secure the top cap through the bottom of the 2x4 or 2x6 into the side of the bottom stair rail post.