Building Outdoor Staircases From Natural Stone or Rock
There are many different options when thinking of building yourself a beautiful set of stone steps. You can choose to use more rugged looking stone which may be a little bumpy or uneven, or you may choose to find some nice and flat stone that may be available in the area or shipped from areas where they are more readily available. The stone should marry well with its surrounding landscape as the surrounding landscape should marry well with your personal tastes and your home.
Once you've chosen your desired stone you now have to decide, if it is an option, the layout and design of your staircase. And keep in mind that your stairs have to be safe and easy to go up and down, even for a child or elderly person. The norm is usually around 8" of rise and at least 12" of run. I normally try to make my steps with 7 to 8" rise and try to get 14 to 16" of run and I usually try to use one solid stone per step, if you have thinner stone than your rise, you will need to shim the face of each step (so that it resembles a stone wall) and fill and compact behind your shims before placing your top step stone. And remember that you shouldn't make too long of run between steps because you may end up with a pace and a half for each step which can be very uncomfortable and awkward to walk up or down. If you need a little more distance for your step you can always add a little curve out one way or even an S shape which will give you more distance between your start and your end.
Preparation and calculations
To figure out your rise and run needed to be able to lay the stone you've chosen, or to be able to choose your stone according to a specific area's needs, you have to measure out horizontally from the to be last step's face to the to be first step's face. And keep your measurement horizontal and as level as possible. Measuring on an angle will give you bad measurements and things will not work out as planned. That will give you your overall run distance of your staircase. The you measure up as vertically level as possible from the base of your first steps future position to the top of your future top step using. If the distances are too great to be able to use a simple 4 or 6' level, you can use a length of lumber or a string to be able to determine your distances. In this case a little help from someone else makes things a lot easier. Now you take your rise measurement and divide it by the desired individual rise of each step and you have determined the number of steps you will need to reach your goal. After determining your number of steps, you can divide your overall run length by your number of steps, minus one step for the top step which will be integrated within the level it reached, and you will see if your run for each step will be suitable to meet your needs. If you need to add length to the individual run of each step you may be able to add a bit of rise to each step to allow you to be able to use less steps and gain an entire steps run to be able to divide over the remaining steps. Or, adding curves, or if the run seems as though it will be too long and uncomfortable between steps, you can add a landing within your staircase.
To prepare the base on which to set your first stone, you have to make sure that the area is at a slightly higher level then the area around it and that it will drain properly. If you don't think that the area will drain well, you should install a drain tile, I use 4" corrugated, surrounded by a thick layer of 3/4" clean drainage stone and covered with a geotextile membrane before you add your final materials, and make sure that the water that will be collected will be able to be evacuated easily at the other end of the pipe. Now you compact. A plate compactor works well to compact the area for the first step, and the you will want to use a manual damper/compactor depending on the size of your stone. Gas powered compactors are very efficient, but may move your steps that are in place if you try to compact behind them with one.
Laying your steps
After your first step is in place, you have to make sure that the face of the step is slightly lower then the back of the step. A good half or full inch is good, things will settle after a year or two. This will allow water to run off each step down to the bottom where it will be able to drain without effecting your staircase. Now, you should have enough room behind each step once laid for your next step and an additional 6 inches to a foot which you will be filling with 3/4" clean stone to allow any moisture collected to drain well. Level this drainage material slightly higher than flush with the preceding step compacting as you add the material until you reach your desired height and then place your next step. If you allow a little more material in the area which will be the underneath of the back of your next step, you may avoid having to lift it to add material to get your drainage slope.
Now that you're on your way up, all should turn out just fine. You may need to retain some of the earth or material either side of some or all of the steps, a stone retainig wall works very well for this and will last as long as your stone step. Otherwise, simply seeding or sodding next to the staircase may be feasible, or even a nice flower bed with a hint of bolderscaping. Just make sure it is in your taste, because it should last as long as you do.