First, build a level landing pad for the stair stringers. You don’t need to pour a footing. Just dig out and compact a minimum 4-in. thick gravel base, then pour a concrete slab or lay paving stones. Lay out and cut the stringers. (See How to Build Deck Stairs for more information.) Make the bottom tread cut 1-1/2 in. shorter than the others.
Install the 2x4 or 2x6 rail cap over the top rail. Predrill 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.
Cut lengths of 2x4 railings to span the distance from the lower posts to the existing deck railing as shown in the image. Attach the railings to the posts with 3” deck screws, making sure the slope matches that of the stairs.
Another way of mounting vinyl railings to a concrete slab is to use the drilling method. You cannot nail vinyl down to concrete, as nailing into the slab is nearly impossible. Instead, special screws must be used that are specially designed to work with concrete.
Every deck with stairs needs a railing to match. Here's how to safely build and install one.
Use a socket wrench to screw on the post holders to the concrete steps. Place the bolt on top of the post-holder screw hole, and then put a washer between the holder and the bolt. You may also want to add a second washer between the post holder and the concrete step.
For a composite railing system, mount the support brackets, which the top and bottom rails will rest on, using two 5/8-inch mounting screws, making sure the hardware screws through the post sleeve and into the wood post.
With the deck floor in place, DIYNetwork.com experts show how to build custom railings using the continuation of deck support posts as mounts for the new railing system.
Whether you need to replace a wobbly old railing or add a railing where there isn’t one already, we’ll show you how to order and install a new one. Iron handrails for concrete steps range in price from $60 to over $150 per running foot.
Before building and installing deck stair railings, we have to attach the deck posts on the deck surface. Consequently, according to the structure of your deck you can either anchor the posts on the floor using post anchors, or you can fasten them to the deck joists using lag screws.
To install stair railing (using the following myCarpentry deck stair design), the stair stringers should already be installed, along with the risers and treads. If they aren't, see the building stairs section for easy to follow instructions.