Building a nice place to walk or sit outdoors is a great project to do yourself. There is a lot of satisfaction gained because you see and use it everyday. For that reason it really pays to do a good job on the foundation of your project. You don’t want to wish later on that you had done a better job.
First steps are important. Some people want to just get it done and will bypass important considerations and preparations. So, here are a few situations you need to watch.
Determine where you want your walk or patio. Look for tree roots that will be difficult to remove, but worse, may come right back and disrupt your finished project. See if there is standing water or a low spot that gets runoff across it and will leave dried dirt on your stone. If so, you have to raise your project to accommodate that situation.
Once you have a good site you need to remove the top layers of soil until you get to the depth you have determined is sufficient. How deep is that? You can use a thinner base for a walkway or patio than you can for a driveway or parking area and the calculations are easy.
First, what is the thickness of your stone? You will need 1.5 to 2 inches of material to set your stone into. You can use sand, but I prefer limestone dust – sometimes called limestone screenings. You also need 3 to 4 inches of crushed stone as a base. So add those up and subtract a half-inch for settling.
For example, say your stone is 2.5 inches thick, your dust is 2 inches deep, your crushed gravel is 3 inches deep – that’s 7.5 inches – and subtract your settling figure of a half-inch – now you know you have to dig a minimum of 7 inches deep. It can be deeper if you remove a stone or root, and just fill in with additional crushed stone, but shallower is not good.
Once you have the depth you need, get a tamper and tamp the dirt down so it is very firm. Add your crushed stone, level it with a rake and tamp it. Add the limestone screenings but don’t tamp them yet. Use a screed to level your area and give it a slight tilt for rain runoff. About 1/16th inch per foot will be sufficient and not be noticeable when you walk on it or sit on it with your beverage.
Now you can lay your stones. Once you have them in place and all your adjustments have been made, tamp them down into the limestone dust base. Put a board or piece of plywood down first so you don’t crack or chip the stone.
If you placed the stone tight together you will have to use fine sand to fill the cracks to tie them together. If you have wider spaces, 1/8 inch or more, you can use more of the limestone dust. Using the limestone is preferred so you will have more stable finished project that will last longer.
You will hear people say to use sand so you have good drainage. You really don’t want water getting under your walk or patio though. It freezes in winter and buckles the stone. Water washes away your sand over time. Weeds will grow in the cracks. If you have a poured concrete walk or patio you don’t drill homes in it for drainage. My opinion is to make your project so the water will run off of it and very little actually goes under it. Make your base stiffer and you will have a project that will outlast you.
Good luck on your project and have fun!