CONSTRUCT A FLEXIBLE-BASE PAVER PATIO, STEP

By Step

Patios make a great place to relax or socialize, and a paversurfaced patio provides a decorative way to build a long-lasting addition to your home. Pavers are available in many sizes and colors, and they can be laid in a number of patterns. Some of these include stack-bond, herringbone, running-bond and basket weave. These standard patterns can also be created in a wide number of variations.

Since patios are typically built with a walking surface just a couple of inches higher than the ground, construction of the patio begins with a lot of excavation.

Most paver patios are built with a flexible base instead of a rigid concrete slab. The patio base is made of at least 4 inches of compacted crushed rock. The depth should measure 4 inches after compaction, which means the base begins with a loose bed about 6 inches deep spread evenly across the patio site. In cold climates where ice heaving is a problem, the compacted bed should be deeper, even up to 8 inches. (Vehicular use requires a base between 8 and 12 inches deep). It’s a good idea for the bed of crushed rock to extend 6 to 10 inches beyond the edges of the finished paver surface.

By Matt Weber

Plan the patio layout by marking it with stakes and a string line. Then measure the area in square feet to determine the amount of materials needed. Estimate the number of pavers based on the size and shape of the pavers that you’ve chosen. For waste, add 5 percent for uncut laid pavers and 10 percent for pavers that are to be cut. Note that cutting pavers will require a brick saw, but the pavers can often be laid in a pattern that requires no cutting.

You will also need to determine the amount of edging material you’ll need by measuring the lineal feet of the exposed patio sides. You have many options for edging material, including retaining wall blocks, staked-down landscape edging, or a concrete berm.

Sand and crushed gravel are measured in cubic yards, and one cubic yard equals 27 cubic feet. Normally, the bed of crushed rock is topped with 1- to 1-1/2 inches of sand. We recommend using concrete sand (rather than masonry sand) because it has a coarse aggregate that resists washing out over time.

To find out the cubic yards needed for every 1 inch of sand bed, multiply the square footage by .00309. To determine the amount of gravel needed for a 4-in. bed, multiply the square footage by .01235.

When calculating your patio dimensions, first determine the finished top surface of the patio and plan in reverse. Most homeowners want the patio surface to be just a couple of inches above the ground, which provides your starting elevation. From that point, measure downward to determine the depth of the digging, based on the thickness of the pavers, sand bed, and crushed rock. Note that for proper drainage, your patio should slope away from the house 1 inch for every 8 feet.

You will need to plan carefully how to manage the delivery and storage of the materials on site. Paver patios are often touted as DIY-friendly projects, but don’t overlook the logistical challenges of moving the materials. Concrete pavers are heavy, and if they aren’t delivered right where you need them, you’ll have to transport them. Iron out these details with your supplier to reduce your labor. Construction of large patios usually requires renting a mini skid-steer and a plate compactor.

Breaking Ground

Before digging out the patio, call 811, which is a free nationwide service that will come to your home and mark the underground utility lines to help you avoid a costly accident.

On the project shown, we used a mini skidsteer for the bulk of the excavation, but the job still required a lot of manual labor to define the edges and to fine-tune the grade. A variety of digging tools will come in handy, including a mattock to pierce the ground, plus a variety of spades, shovels, hoes, etc.

After the site has been graded flat, we used a vibrating plate compactor to tamp down the soil. Proper compaction is critical to all phases of a patio project. We recommend that you compact the soil, compact the gravel base, and even compact the patio surface to ensure the pavers are firmly set in the base. (Note: At the rental outlet, request a rubber footplate for the plate compactor to prevent damage to the paver surface when compacting it.)

As an extra level of weed protection, we applied landscape fabric over the patio site before construction.

Decide the height of your patio as your starting point, then add up the material layers and work downward to determine your depth of excavation. A variety of landscaping tools will come in handy for the digging.

For best long-term results, tamp down the excavated ground as well as each material layer of the patio. Cover the compacted earth with landscape fabric.

Next, the landscape fabric is covered with crushed rock. Spread the rock evenly on the site before compacting it. A landscape rake can be particularly useful to spread the rock because it has a broad metal head with rigid tines to move the heavy material.

Since the sand bed will be screeded to match the rock bed, it’s important to engineer the patio slope into the crushed rock. We used a string level to keep an eye on the slope (along with a 2x4, which we used as a gauge to represent the thickness of the paver surface plus the sand bed.)

Once the rock bed is graded to the right slope, compact it with the plate compactor.

Spread the crushed rock and compact it. We used a line level to ensure we had a slope of 1” per 8’ away from the house. A 2x4 laid on its edge (3-1/2”) served as a makeshift depth gauge to represent the thickness of our pavers (2-1/2” thick) plus the sand bed (1”).

Sand Bed And Pavers

Next, comes the sand bed, which can be screeded perfectly smooth before applying the pavers.

For large patio areas, you might find it easiest to form the sand bed in sections. We used 1-inch PVC pipes to form the sections. The pipes served a dual purpose: (1) as a continuous depth gauge for the sand bed and (2) as the guide-rails for our screed tool.

Our method: Lay the pipes parallel to each other 3 to 4 feet apart and pour the sand between them. Use a hoe or rake to spread the sand roughly throughout the section. Use enough sand that it piles above the pipes. Then, use a screeding tool stretched flush across the two pipes to strike off the excess sand and level the 1-inch bed flush with the top edge of the pipes. We used an aluminum straight-edge as a screed tool, but a 2x4 board can also be used—just make sure it is perfectly straight. Remove the pipe that is nearest to the edge of the patio, fill its indentation with sand, and trowel it level with the surrounding bed.

We then laid pavers over the completed section of sand bed. Begin laying pavers in one corner of the sand bed, carefully adhering to the layout pattern. Use a rubber mallet to set the pavers into the base.

Once the pavers are complete in that section, move to the next area of the patio site and lay the pipe parallel to the one already in place (3 to 4 feet away). Add sand between the pipes and repeat the screeding process. Then add the pavers. Work from section to section until you’ve completed the paver installation at the opposite end of the patio.