The most popular type of patio surface these days is one made of clay brick or concrete pavers loose-laid upon a base of compactable gravel covered by a sand layer. Poured concrete is still an alternative for a patio, but pavers are both more attractive and more suitable for DIY installation. This technique, called a "sand-set" patio, can also be used for slate, flagstone, and other natural stone, but brick or concrete pavers offer the huge benefit of being uniform in size, allowing for precise installation and a variety of patterns.
The seams between bricks or concrete pavers can be mortared—this was once the standard technique for laying down brick paving surfaces—but these days, it's much more common to lay them loose, then fill in the gaps with a fine-textured paver sand that fills the cracks between pavers and locks them into place. Done correctly, this creates a very durable, stable surface, but one that also can be fairly easily repaired if areas begin to sag.
The two most important elements of successfully laying sand-set paver patio is getting the layout and pattern right, and creating a building site that is very flat, but also slightly pitched so that water can run to one side. One of the advantages of a sand-set patio is that water will seep through the sand joints, but you should still make sure the overall patio slopes away from the home at a pitch of roughly 1/8 inch per foot. This means that a 10-ft.-wide patio should be lower on one side by about 1 1/4 inch. You don't have to be too obsessive about this, but do take pains when you are creating your patio base to make sure the gravel sub-base and the sand bedding layer or slightly pitched away from your home.
There is disagreement over whether the pavers on a sand-set patio should be treated with a sealer after installation, and as part of routine annual maintenance. The best advice is to follow the suggestions of the paver manufacturer regarding this. In particular, patios made from traditional clay brick may require sealers. A sealer will also have the benefit of helping the sand remain locked into the joints, but it may also hinder the ability of water to seep through the patio joints and into the ground, as intended. A sand-set patio that has been sealed may actually be prone to more water problems.
Installing a large patio, especially one with a very unique or unusual pattern, is a complicated process, and you should study up on how it is done. This article will give an overview of the process, but also consult the installation literature provided by the paver manufacturer.
Create a working plan on graph paper. Begin by measuring your patio site, then use these measurements to draw a sketch of your patio to scale. Remember that choosing a relatively flat and level site will make your work easiest. Then choose the type of pavers you want. Pavers come in a variety of shapes, sizes, colors, and materials. Paver manufacturers may offer literature with ideas for different patterns you can use, and the layout you choose will determine not only the quantity but also the kinds of materials you need. A basic square or rectangular patio will be relatively easy to layout and install, while one with curves or rounded edges will require a substantial amount of cutting of pavers. Order your materials now. It's always best to order about 5 percent more than you will need to accommodate mistakes and breakage.
Lay out the patio on the building site, using stakes and strings and using your planning drawing as a guide. The easiest way to do this is by driving vertical stakes into the ground then using layout strings to outline the boundaries of the patio. If you are installing a curved patio, use a garden hose or ropes to outline the contours of the patio.
Excavate. Use a shovel and rake to remove lawn grass and smooth out the bottom of the patio site. The excavation should be about 1 ft. wider than the planned patio to give you room to work. The depth of your excavation should be about 6 to 8 inches to allow for the gravel sub-base, the sand bedding layer, and the thickness of the pavers. This is a considerable amount of work, so having helpers is a good idea at this stage. Take pains to get the excavation site as flat as possible, as this will make the next steps much easier. A long straight 2 x 4 can be used as a straightedge to judge the flatness of your excavation site.
Install gravel subbase. Now lay a 3- to 6-inch layer of compactible gravel over the bottom of the excavated area, spreading it evenly. Use a long 2 x 4 as a straightedge to judge the flatness of the subbase, and use a level to make sure you are maintaining a slight slope away from your house to facilitate drainage (about 1/8 inch per foot).
Pack the gravel. Use a hand-tamper or rented power tamper to firmly compress the gravel layer. This is an important step, as you want the firmest base possible for your patio so that it does not shift or sag over time.
Lay landscape fabric over the patio site. This will keep weeds from growing up through the pavers, and it will also provide a surface to keep the sand from seeping down into the gravel. Overlap sheets by at least 6 inches.
Install paver edging. Although it is possible to simply butt your patio up against surrounding soil, installing a plastic paving edge with stakes will help confine the sand base and may improve the stability of your patio over the long term. Most paver edging can also be bent to conform to rounded patios.
Lay base sand. Spread a 1-inch layer of coarse sand over the landscape fabric to form the bedding layer for the pavers. Use a long 2 x 4 as a "screed" to level and smooth the sand, and make sure to maintain the slight downward pitch (1/8 inch per foot). This is a tricky part of the process, but taking pains to get it right can spell all the difference in the final results. Use a long 2 x 4 and 4-ft. level to judge the slope of your patio base.
Lay the border pavers, if you are use a contrasting type of brick or a different pattern. Use a 1/8-inch spacer to maintain a uniform gap between pavers. On slightly rounded patios, you can lay the pavers so there is a wedge-shaped gap between them; for tighter curves, you may need to use a masonry saw to cut them into shapes that will conform to the curves.
Set the field pavers, beginning at one side of the patio. Following the design you've selected, begin applying the paver bricks in one corner of the patio and fan out in all directions as you go. As you go, use a rubber mallet to lightly point on the pavers to "set" them into the sand. Use a 4-ft. level or 2 x 4 straightedge to make sure the surface is remaining flat as you go. At the far side, you may want to reposition the paver edging (if you used it) to minimize how many pavers you need to cut.
Lay the cut pavers, if necessary. If your design requires angled pavers or partial pavers, use a power masonry saw to cut them. As you reach rounded borders, you can position full pavers and mark the edges where they will fit against the border pavers. Then cut them with a masonry saw (available at tool rental stores). Cutting pavers is a very loud and dusty job, so make sure to use ear protection and a particle mask.
Fill joints with paver sand. Spread out fine-textured paver sand over the finished surface with a push broom, moving it back and forth in opposite directions until the joints between pavers are completely filled. Use a hand- or power-tamper to pack the pavers down into the base layer to settle the joints, then add more sand, as needed. Soak the surface by spraying it lightly with water. Let the surface dry for a full day, then add more sand and tamp again if necessary. Sweep the patio surface clean.
Seal the pavers? If the paver manufacturer recommends it, use a liquid sealer to seal the surface of the pavers and the joints. This will be recommended for some types of pavers—especially clay or brick pavers with porous surfaces—but may not required or even discouraged on other types. Where recommended, these sealers can usually be applied with a pressure sprayer. Repeat the sealer application at the recommended interval—usually annually. For sand-set pavers, the recommendation will usually be for a water-based rather than solvent-based sealer.