Proper Alignment is Important in Brickwork

CALIFORNIA - Landscaping or building an outdoor patio with brick pavers is a surprisingly simple job. Here are some guidelines for success from the Brick Industry Association.

To get started, you will need brick pavers, which are different from the brick used on house walls. Pavers are solid, without holes, and vary in size, style and color. They generally come in either a 1 1/4- to 2 1/4-inch thickness and are either 4 by 8 inch, 3 5/8 by 7 5/8 inch, or 3 3/4 by 7 1/2 inch.

Besides the pavers of your choice, you will need sand that holds the brick in place and crushed stone that creates a strong base. Use only well-graded, washed concrete sand.

Crushed stones should range in size from about 3/4 inch down to fine dust. Crushed stone goes by several names - gravel, road base or crusher run are common names.

You have several choices in selection of border materials - brick, rigid plastic or metal specifically intended as edging material, or 2-by-4-inch or 4-by-4-inch wood, which can be either pressure-treated or natural redwood. For wood, metal or rigid plastic, you'll need metal spikes that are at least 8 inches long.

For aligning brickwork, you need string and wooden stakes. Recommended tools include a flat shovel, wheelbarrow, garden hose with fine spray nozzle, hard garden rake, carpenter's level, wood "screed" strip (a 2-by-4-inch piece of wood at least 3 feet long is adequate) used to level and create a uniform sand depth, trowel, broom, plate compactor (rented), and an electric drill with appropriate size bit (for wood edging only). A broad-blade chisel is needed (a brick splitter or masonry saw that can be rented at your local store, or a brick distributor can be used instead of a chisel and probably better for cutting and fitting the brick).

Begin by determining the square feet (length time width) of the area you want to pave. Estimate the number of pavers needed: For 4-by-8-inch pavers - 4.5 pavers per square feet; for 3 5/8-by-7 5/8-inch pavers - 5.2 pavers; for 3 3/4-by-7 1/2-inch pavers - 5.1 pavers.

A brick supplier can help estimate how much is needed and help with the pattern. You must decide on a detailed design before you begin any installation. Be sure to add 5 percent extra for chipped or broken pavers.

For edging materials, measure the linear foot of open edges - those not up against a house, curb, driveway, etc. This is the number of feet of edging material you will need. If you plan to edge with brick standing on end (soldier position), calculate one brick for each 4 inches of edge. For wood or rigid plastic edging, plan on one stake for each 2 to 3 feet of edge.

The sand and crushed stone required for your project will be measured in cubic yards (1 cubic yard equals 27 cubic feet). For any type of paving project, whether patio, walkway or driveway, you will need a 1-inch depth of sand. To determine the number of cubic yards of sand, multiply the square footage by .00309.

The amount of crushed stone you will need depends on the type of paving project. For light-duty projects - such as walkways or patios - use 4 inches of crushed stone. To determine the cubic yards for a 4-inch base, multiply the total square footage by .01235.

For heavy-duty projects - such as driveways - you will use an 8-inch base of crushed stone. Determine the amount needed for an 8-inch base by multiplying the total square footage by .02469.

In areas of extreme wetness or severe freeze/thaw cycles, you may need a deeper base. Consult your local brick distributor for recommendations.

Before preparing your work, check with your utility company to determine the location of underground lines. Also, be sure that the area you intend to pave has proper drainage. A 1/4-inch per-square-foot slope away from foundations or other permanent structures is needed.

Prepare the site by outlining the area to be paved with stakes and string. Make sure that you include the width of your edging material. Use a flat shovel to remove only enough sod or dirt to provide a flat, level surface upon which to place the crushed stone base. It is important that dirt or excess soil that is removed and re-installed be firmly settled with a plate compactor for an even, solid base.

After compacting the soil, place the crushed stone base into the excavation. Using a plate compactor, tamp down no more than 4 inches (depth) of base material at one time. This is a critical step - if not done carefully and thoroughly, the brick pavers will move over time. The base material should be kept slightly damp when compacting.

A border, or edging system, is an important element necessary to ensure that your brick paving remains firmly in place and stays beautiful for years.

Begin by installing, but not anchoring, your edging. Experiment now by temporarily laying the brick along the interior edges of the border according to your preplanned pattern. This will give you an opportunity to precut the pavers required for a fit within the border edges. Once you are satisfied with the temporary placement of pavers, you can anchor the edging by driving spikes at least 8 inches into the base every 2 to 3 feet.

For wood edging, drill holes and drive the spikes through the middle of the wood. For brick edging, dig a trench deep enough so that the top edge of the edging brick will be flush with the brick surface of your finished project.

It is best to leave one edge of the border perimeter unanchored to accommodate adjustments in the final setting of the bricks to assure a tight fit. Now remove the bricks you temporarily installed, and lay the bed of sand.

For a walkway or other fairly narrow project, use 1-inch outside diameter pipe or cut two wood strips to the desired height of sand (1 inch). Place them on either side of the paving area. For a wider project, like a patio, place the strips about 3 feet apart.

The sand can be dampened with a fine mist of water prior to installation to eliminate voids. After you pour the sand, use the pipe or wood strips as rails on which to run your "screed" board to ensure a uniform sand depth of 1 inch. Be careful not to walk in or disturb the leveled sand.

Remove the screed rails and fill the indentations with loose sand. Level with a broom or trowel.

Start laying the brick in a corner - if possible, one that includes an edge, such as a house, curb, sidewalk or other fixed edge. Lay one run of brick from the corner along the two adjacent borders.

As you set the brick in the sand, don't press or hammer them into place. They should fit snugly, with about 1/16-inch or 1/8-inch gap between each brick. Be sure to work from laid brick, not the sand. If you disturb the virgin sand, re-level it with a broom or trowel before laying more brick.

Continue to lay the brick in your pattern, working from your starting corner to the unanchored edge. With the original perimeter brick as a reference, put a string line across the front of your laying edge (every 2 to 3 feet) to maintain alignment. If the pattern wanders somewhat, a trowel, screwdriver or wide-blade utility putty knife can be used to make small adjustments.

Don't be concerned with the small gaps between the paving brick - you'll fill them with sand. Be sure to check the level and alignment of the brickwork frequently during installation. Once all the full brick have been installed up to the final, unanchored edge, cut or saw the remaining brick to complete the pattern - but ensure that the final edge brick are no smaller than 2 inches in width. Anchor the final border when brick installation is complete.

Make a final inspection of your work, adjusting brick height and joint alignment as needed. Then sweep dry sand into all joints to lock the brick into place. To further set the brick, you may want to use the plate compactor to gently tamp it down. If a compactor is used, spread a layer of sand over your pavers to prevent contact between the brick and the compactor.

The sand you sweep into the joints will gradually settle. You should sweep additional sand into the joints as necessary over the next few rainstorms until the bricks are fully stabilized.