Building Deck Stairs and Railing

First, we’ll show you how to build deck stairs. Your deck stairs should be at least 3-feet wide for ease of traffic flow and safe use and most codes require a 3-foot minimum anyway. Once you’ve figured out how many steps you need, you’ll need to cut stringers. Stringers are the wooden frames for the steps. Use a framing square to transfer the measurements to a piece of lumber.  After you’ve marked off all the steps, use a circular saw to cut most of the way, and then a jigsaw to finish the cut. Try not to cut past the mark in the corner because this will weaken your stairs. You can then reuse your first stringer as a template to trace out any additional ones you’ll need.

How to Build Stairs with a Landing 

How to Build Stair Stringers 

You should assemble the stairs on the ground first, which will allow you to locate your posts and set the stair height accurately. Continue installing your stringers 16-inches apart for the width of your stairs. Now you’ll need to attach the stairs to the deck. First, we install a stair hanger or crossbrace, constructed from 2” x 10” boards. Temporarily attach your stairs to the deck to mark the locations for your postholes. Mark your postholes, pour the concrete, place your posts and level them and then attach them to the stairs.    

For the treads, if you’re trying to keep the look consistent with the rest of your deck, use the same decking boards as you used on your deck. Attach the treads with deck screws and then notch the bottom tread around the post for a nice finished look.    

Most building codes require railings for decks over 24-inches in height and most codes require these railings to be at least 42-inches high. Start by dividing the spacing of the posts to create equal distances for each rail section. The posts may be positioned anywhere between the joists. Box in the post to the framing using the rim joist as the front support and blocking to support the back and sides if required. The blocking should be the same dimensions as the joists. Next, mark the location of each post, drill a pilot hole and then cut out the post location with a jigsaw.

How to Install Railings on a Deck 

Now we’ll show you how to build a deck railing. Rails are installed so that we will have something to attach the balusters or pickets to. We are using 2” x 4” boards for our top and bottom rails. Install the plastic mounts that came with your railing kit and attach the bottom rail. Once the rails are screwed to the posts, attach the balusters. By code, balusters have to be close enough together so that a 4-inch sphere can’t pass between them. After the top and bottom rails are in place, use a circular saw to cut the top off the post. This makes it flush with the rail. Repeat the process for the rest of the deck rails.    

To finish the railing, all that’s left to do is to install the top piece, called the cap rail. Lay the cap rail over the balusters and posts and attach it with decking screws. Continue this around the perimeter of the deck, mitering the joints where cap railings meet.    

As a nice finishing touch, make angle cuts on the corners of the cap rails. Your deck is almost done, but there are still a few finishing touches that you can do to make it even sturdier and last longer. Adding structural post-to-beam supports to every post and bolting the cradles to the posts with lag bolts will make your deck structure even more sturdy. Apply sealer to the cut ends of all boards to help protect it from weather and insects. You now have a completed deck.    

Periodic application of a high-quality, clear water repellent or semi-transparent stain with water repellent helps to minimize warping, splitting, and other weathering problems. You may need to wait a certain period of time after you build your deck to apply the sealer or stain if you used pressure-treated wood, as it is usually wet when new. Consult your wood manufacturer’s recommendations on any waiting times. Remember, it’s important to regularly maintain any deck, no matter what it’s made of.