How To: Install concrete pavers
An important part of any successful landscaping project is choosing the building materials that will provide the look and durability you desire. Whether designing a patio or walkway, interlocking concrete pavers provide aesthetic beauty, functionality and durability for a project that will look great for years to come.
Versatility in design
Concrete pavers offer the color, texture and fit to overcome almost any design challenge. Pavers are available in a variety of colors, shapes and sizes, and you can blend textures to resemble more expensive materials without bankrupting your budget.
Tumbled pavers, with their rough edges, have an appearance similar to stone or slate.
Bush hammered or shot-blasted pavers feature a rough, stone-like finish.
Ground pavers are smooth and made to look like granite, marble, terrazzo and other cut stones.
When installing an interlocking concrete-paver system, 90 percent of the work involves preparation of the subsurface. In fact, you will do most of the work on the paver project--planning, excavating and preparing the base--before you lay a single paver.
Step 1: Planning
To begin, take some graph paper, a level and a garden hose, and start experimenting to determine the shape and size of the project area.
- Spread the garden hose around the area, using 2 x 4s to show the straight edges. Remember that pavers offer you a great opportunity to be adventurous. Sketch a mosaic pattern on the graph paper, or try accenting a small pond or garden sculpture by changing patterns and colors, or add interest by adding a border to the project.
- Use the level and a 2 x 4 to check for the correct slope. For proper drainage, the pavers should slope at a rate of 1 inch for every 5 to 8 feet. After deciding on a shape, outline 5 to 8 inches outside the pavement edge with spray paint. The extra inches allow for adequate working space and edging materials.
- Once you determine the size and shape of the project, it's time to decide how many pavers you need. When working on a project without many curves, simply estimate the square footage of the space and add 5 percent. If you have a lot of curves or a paver border, add 10 percent.
Step 2: Excavating
Keeping in mind the needed slope, now is the time to decide the finished height of the project.
- Use the bottom of a door or any permanent structure that abuts the project as a reference.
- Place stakes at varying intervals along the outline of the project.
- Take a long 2 x 4 and run the board from the abutting structure to a stake. After checking to make sure the board is level, mark the stake at that point, and then make another mark further down the stake based on the determined slope.
- Run strings, tied to the stakes, across the length of the site to indicate the desired finished height.
To lay an adequate amount of crushed aggregate stone base, bedding sand and pavers, excavate the site well below the desired surface height of the project to allow for the base and sand layers. Simply calculate the thickness of the base, sand and paver layers to determine the depth.
After excavating the site, compact the soil with a plate compactor to prepare the surface for the aggregate base. Remove any standing water, rocks or other protrusions. Any bump or depression at this or any level will become visible in the finished project.
If the soil is clay, place a geotextile layer over the exposed soil and up the sides of the excavated area. This will provide additional stability for the base.
Step 3: Laying the base
If possible, use crushed rock for the base, the same material often used under roads. The climate and type of soil under the base determines the thickness of this layer. Cold regions with fine clay or silt require a thicker base than well-drained soil in a warm climate. Typically, 4 inches of base will be adequate for a patio. If any areas need to be built up, do so with the base material. Lay the base far enough past the true outline of the pavement so that it extends past the edge restraints at least the same dimension as the thickness of the base (4 inches or more). Compact the base in 3-inch layers using a mechanical plate compactor. For best results, work the compactor in a circular motion and go over all areas at least twice. If the base is dry, moisten it with a garden hose (but don't saturate it) before compaction.
Step 4: Restraining the pavers
Edge restraints hold the concrete pavers and the base in place. Without edge restraints, pavers can shift, and the base can erode. Restraints can be made of steel, aluminum, precast concrete or plastic. Secure plastic or metal edge restraints in place with 12-inch spikes. For projects with several curves, you can cut the edging to follow bends in the shape of the project.
Step 5: Setting the sand
Sand is the final layer of the base for an interlocking concrete-paver system. For this layer, use coarse sand, such as the kind used to make concrete. Don't use limestone screenings or stone dust. When screeded smooth, the sand should be no thicker than 1.5 inches and perfectly smooth.
For smaller projects, drag a screed board with a 2-inch notch along the edge restraints.
For larger projects, lay 1-inch-diameter pipes on the base and screed the sand along the pipes.
Remove the pipes and make sure to fill in the grooves left by the pipes with sand. Work in small areas by screeding the sand in 50- to 100-square-foot sections and lay the pavers before screeding the next section.
Step 6: Placing the pavers
Now comes the simple part--actually laying the pavers in place. To keep pavers in line, you can use the height string as a guide for the pattern of the pavers. You may need to pull out and set additional strings to mark joint lines.
Gently fit pavers tightly together in the appropriate laying pattern. When necessary along the edges, cut the pavers with a masonry saw or mechanical splitter for a perfect fit. Lay all whole pavers in place before adding the cut pavers. Also, always wear safety glasses when using a masonry saw or mechanical splitter, as well as any other safety attire recommended by the equipment manufacturer.
After you set all pavers, use the plate compactor again to vibrate and set the pavers into the bedding sand. For the final step, sweep sand into the joints of the new patio, driveway or path, and compact the surface again, sweeping sand into them until the joints are full. You can use the same coarse sand used for bedding the pavers, but finer sand will fill joints faster. But be careful what type of sand you use--sand that is too fine will not provide for sufficient interlock. Make sure any sand you use is completely dry so that it fills the cracks and provides the interlock that will keep all the pavers in place.
A job well done The finished product is not only aesthetically pleasing but the interlocking concrete pavers should last 20 to 30 years. They are a cost-effective alternative to other types of paving materials.
David R. Smith is the director of the Interlocking Concrete Pavement Institute (Sterling, Va.).
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