Now that you have your deck built you move on to what some call the trickiest part, and that is designing and building your stairs. This is tricky because there are so many things you have to take into account. You can’t just slap some wood up next to your deck and call them stairs. Most building codes are strict when it comes to stairs, most require stairs for decks that are 12 inches or higher. Stairs consist of two items, treads and stringers. Treads are steps, which are supported by stringers and are usually 2×10’s or 2×12’s. Stringers should sit squarely on a concrete pad, their inside edges should be at least 2 inches from the side of the pad closest to the deck. Stairs are usually a minimum of 36 inches wide, if they are any wider they will usually need more support than normal.
First you have to plan your stairs and here is how you do it. You’ll have to figure out the number of treads, the rise between treads, and the total run of the steps. Here are four steps to figure out how to plan your stairs. 1. To find the approximate number of treads divide your deck height by 7 inches which is the typical rise between treads. 2. To find the actual number of treads round off to the nearest whole number to find the actual number of treads. 3. To find the total run of the treads multiply the number of treads by 11.5 inches to find the total run of the treads. 4. To find the actual rise between treads, divide the deck height by the number of steps plus1, this will give you the actual rise between the treads. Once you figure these steps out you now have your calculations ready to apply to actually building your steps.
Now that you have all your calculations ready you can decide whether you want to use a closed stringer system or an open stringer system. With closed stringers, treads are supported by cleats fastened to the inside face of the stringers. The stringers are attached to the edge of the deck with screws and angle brackets. They’re anchored to a concrete pad with angle irons and J-bolts, washers, and nuts. The stairs should be a maximum of 36 inches wide. The treads are made of two 2×6’s, separated by a 1/2 inch drainage gap which will make a step 11-1/2 inches deep. To be comfortable, the rise between steps should be about 7 inches, you will already know what your rise is and if it is within 1 inch up or down of 7 inches, you should be OK. If they are not, you may want to make some adjustments to either the angle or the run. Open stringers need no metal cleats, the stringers themselves are cut along the rise and run lines to support the stair treads. The treads can be nailed flush with the outside edge of the stringers or overhanging them slightly. You will lay out open stringers just like the closed stringers. There is one important difference though and it really does need to be addressed. Since the thickness of the first tread will add to the rise of the first step you ‘ll need to subtract and cut off that amount from the bottom of the stringers. The nice thing about open stringers is that you have a choice to either build your own or buy them. These stringers are available pre-made at most builders warehouses. With open stringers, the treads are nailed directly to the stringers themselves. The stringers are attached to the deck’s face board with angle brackets. they’re anchored to a concrete pad with angle irons and J-anchors bolts, washers, and nuts just like the closed stringers.
OK, now that we have all the technical stuff out of the way here is how to actually make stairs, first you need to measure and cut your stringers. With gauges, mark the step’s rise measurement on the short arm of a framing square and the run on the long arm. This number will come from the calculations you have already found. Place the square against the stringer and mark a bottom rise line, then extend this rise line across the stringer. Position the square in place against the guides and trace along it to lay out the first run and second rise. Slide the framing square and gauges into position along the edge of the stringer, then outline the next run and rise. If you try to visualize a staircase when you are doing this it will help you see the whole picture. Just continue this process until you have the outline of the entire stringer. Once you have drawn the line for the last rise, extend it across the stringer to mark the top end of the steps. Cut the stringer along this line with a circular saw or you can even do it with jig-saw if that is all you have. If you do it with a jig-saw get a thick blade and use a guide or your stringers will be wavy, and you don’t want that. Next measure along the bottom rise line starting at the top edge of the stringer and make a mark at the rise height. Draw a line at 90 degrees across the stringer at the mark. Make the cuts for the bottom of the stringer with a circular saw. Parallel to each run line you need to draw a second line to indicate the bottom edge of each tread. Once you have done this to one stringer, simply duplicate fir the second. Position a tread cleat at the bottom of each tread outline, then mark and drill pilot holes slightly smaller than the lag screws you’ll use and fasten the cleats in place.
Now you need to know how to assemble the stringers and treads for a closed stringer system. Since the treads in an open stringer system are nailed right to the stringers themselves I don’t think I need to go into that, simply nail your treads on the stringer. For closed stringer applications you need to nail one side of an angle bracket to the top of each stringer with 3d 1-1/4 inch nails. Position the stringers against the face board and drive nails through the other side of the brackets. Then fasten an angle iron to the base of each stringer with 3/8×1-1/2 inch lag screws. Fasten the angel iron to the J-anchor bolt in the concrete pad you have already poured. Finally cut pairs of 2×6’s to length and attach them to the tread cleats, using a nail as a spacer to separate them. Secure the treads with lag screws in drilled holes. You are done, and the hardest part of the deck is complete.
I mentioned earlier that you will be connecting the J-bolt in the concrete to the hangers. Well, the concrete pad is just like pouring a patio which I have an article about. Read this article about pouring a concrete patio and you will know how to do it. It is just like pouring a patio except you will be placing J-bolts in the wet concrete to secure the bottom of the stringers in. The next thing you will be doing on your deck is probably the railing, I will be creating an article to walk you through the railing process. Good luck with the stairs.
