Garden Center Tips: Laying a Flagstone Patio

Your outdoor spaces can work as hard as your indoor spaces. By creating “rooms” with plants, shrubs, trees, and decks or patios, you can enjoy the great outdoors in many ways, even in climates with cold, harsh winters. The fall and winter seasons are the perfect times to begin plotting out your landscaping fantasies before hitting your favorite garden center in Brooklyn with your to-buy list when spring arrives. A flagstone patio creates an organic looking surface on which to set up dining furniture, an outdoor kitchen, a fire pit or fireplace, and potted plants for a private, shady outdoor room. Laying flagstone isn’t difficult, and you can get started as soon as all danger of frost or freezing has passed. Ask a friend or two to help, because laying such a patio is heavy-duty labor and requires some basic to intermediate mortaring skills.

Building a Concrete Pad and Making the Forms

Because flagstone is a natural, uneven stone, you will need to set your patio over a concrete pad. The concrete provides a very even surface over which you will need to slather a relatively thick one-inch layer of mortar. This thick mortar layer will allow you to set the flagstones so that the patio floor is smooth.

Once you have your concrete pad completed and dried, you can begin using your 2X lumber to create the form for the mortar. Use stakes driven every two feet and three-inch duplex nails to position the form one inch above the concrete slab. The more regular the shape of your patio, the easier it will be to build the forms.

Lay the Stones

Pile all of the flagstones into the patio area and begin laying out the stones so that there is as little space between them as possible (there will be inevitable holes in your design). Cut stones as needed to fill in large gaps. Once you have all the stones placed how you like, turn them over and number them for future reference.

Adding Mortar

Mix your mortar until it is firm enough to cling to a trowel turned on edge, which may require more or less water than the manufacturer’s instructions. Use a mason’s trowel to spread the mortar one inch thick in an area large enough for two or three stones. Screed the mortar with a 2X4 laid over the width of the forms. Then lay the stones into the mortar, embedding them firmly by tapping them with a rubber mallet. Level as you go, using more or less mortar under the stones in order to keep the surface of the patio as even as possible. When all the stones have been laid in 4X4 sections, let the mortar dry for two days before removing the forms.

Now you can mortar between the stones, packing it in with a pointing trowel. Create neat joints between stones by compressing and smoothing the mortar with a ¾-inch brick joiner. Clean up mortar crumbs around the edges. Let the mortar dry for a few hours before using a damp sponge or burlap rag to wipe away excess mortar. Cover the patio with a plastic sheet to let the mortar cure for 24 hours. After you have backfilled the edges of the patio with soil, you are ready to revisit your favorite garden center in Brooklyn to purchase plants and flowers that will add beauty and color to your new outdoor room.