Romancing the Stone
By Gary Hayes
Published: 06/21/2009  Updated: 08/14/2019
A flagstone patio can bring natural elegance to your outdoor space.
A flagstone patio can bring natural elegance to your outdoor space.  Photo by Gary Hayes

Adding a flagstone patio will expand your outdoor living area and add visual interest to your landscape. Following a few basics will give you a sense of accomplishment and avoid the pain of having to do it over.

Laying a flagstone patio is a project any homeowner can accomplish if you're willing to get down and dirty, properly prepare the site and you have some adeptness at jigsaw puzzles. The area must be prepared by digging deep enough to allow for the one to three-inch stone and at least an inch of sand to bring your new patio up to the desired height. This is especially critical if you must match the level of the patio to existing steps or walkways. Clear, rake and level the site, allowing for some flexibility in dealing with stone that can vary in thickness by two inches. Hand selecting stone of a similar thickness will make your job easier, but flagstone for larger jobs is typically delivered by the pallet and you'll need to be able to accommodate these variations.

Dig out at least four inches below any existing hardscape that you are trying to level. Once the area is cleared and roughly leveled (giving some consideration to drainage), lay down a weed barrier to make maintenance of your new patio easier, then add approximately three inches of sand. Smooth and level the sand with a 2-by-4 board and tamp down with a hand tamper or lay down a small piece of plywood and stand on it to pack the sand. Do your best to achieve an evenly packed and level surface to make leveling the stones easier. Once the surface is prepared, you can begin to lay stones working from the outside edges in. Level the stones as you go. A rubber mallet may help seat the stones in place. You'll need to make a decision about spacing and be consistent. For seating areas, stone should be tight, whereas walkways can be more openly spaced. This jigsaw puzzle can get more difficult as you finish filling the center areas, and stones may require chiselling to make a piece fit.

When your flagstone pieces are laid and level, pour sand over the stone, sweep the sand into the cracks and gently hose off the patio. Continue to add sand and hose off the flagstones until the cracks are filled. You can also use mortar as an alternative to sand, but this can detract from the natural look of flagstone, will prevent drainage and can make future maintenance a bigger job as the mortar eventually cracks.

You can also lay flagstone over an existing concrete pad, adding at least an inch of sand for leveling and accommodating varying thicknesses of flagstone. With a concrete pad, thinner pieces of stone may be used without compromising strength.

As your patio settles, some stones will likely need to be releveled, but this is an easy job of lifting the stone and packing in additional sand with your fingers, fill cracks with sand, sweep, rinse and repeat.

When your new patio is laid and leveled, consider what you want between stones. There are many mosses and ground covers that can stand up to foot traffic and are an effective way to soften edges and bring a natural look to your work. Other options include placing small stones, pea gravel or even a few surprises, like beach glass details, to some of the spaces between stones.
Romancing the Stone