Replacing Bricks in a Patio

Patio bricks set in sand are simple to replace. The most difficult part of the job is removing a broken brick without damaging its neighbors. If the patio bricks are mortared or set in concrete, use a cold chisel and baby sledgehammer to chisel out the damaged brick carefully, breaking off and removing small pieces so you do not crack the surrounding bricks or mortar. Chisel away the mortar joints and concrete bed too. Brush latex bonding agent into the cavity and set the new brick in a bed of mortar.

Tools: Flat pry bar, hammer, cold chisel, 4x4 for tamping.

1. Remove the damaged brick. Use a flat pry bar to pry out the old brick. You may need to crack the brick and take it out in pieces. If it is a tight fit, try using two putty knives or trowels, one on each end, to shoehorn the brick straight up.

2. Tamp and replace. Add sand and tamp the area well, making sure the sand level is not too high. Replace the brick and tap it level with a hammer and a piece of scrap wood. Fill the joints with fine sand, brush, and spray with water. Repeat until the sand remains at the level of the bricks.

Planning Driveways and Walks

Walkways and driveways should be both practical and good-looking. Begin your designing process by determining the natural paths people take to doors and any high-use areas. Avoid building a walk that will be bypassed in favor of walking on the lawn. Concrete is not a beautiful material, so use it as a frame to outline your lot. Add variety by combining other paving materials with concrete.

Once you have a general plan, visit your building department to find out about the zoning regulations and building codes governing your project. Codes typically dictate the dimensions and type of concrete you must use for footings and slabs. They tell you how much and what type of metal reinforcement to use and if you need a sand or gravel base under the material. Building codes also spell out setbacks—how far from the property line your building must be set. Once your plans are approved, you can get a building permit. Plan the work schedule so you will be ready for each inspection.

Make a total plan. Planning starts with knowing what you want. Short of hiring an architect, the best way to get ideas and a sense of style is to drive around town and look at other people’s drives and walkways. Use concrete in places where you need solid strength. But large concrete slabs can pose a drainage problem. You may need to install a drain in the middle of the slab, make sure the slab drains into the street, or provide drainage around the edge of slabs. For patios and walkways, you usually can install a surfacing material, such as bricks, pavers, or loose material for about the same price as a concrete slab. If built well, many such surfaces hold up as long as concrete.

Plan a patio slab. As you plan for and design a patio slab, be sure to locate it away from large trees whose roots may crack it. You may need to remove roots as you grade the excavation and before you add the sand or gravel base. Slabs collect a lot of precipitation, so slope the slab away from the house. Also, it should be no closer than 1 inch below a door sill or threshold. Because concrete does not flex without cracking, you’ll need to add reinforcing mesh. Control joints allow the slab to flex without creating unsightly cracks. Expansion joints provide a buffer between the house foundation and the slab. Select a finish and plan on having an experienced finisher on hand.

Caution! Watch Underground Lines - Avoid placing structures over underground septic systems and gas, water, electric, and telephone lines. Locate all underground utilities on your property. You may have to call each separate utility company to locate each line. Find out how deep the lines are buried and if your project might harm them. If lines need to be moved, you probably will not be able to do it yourself— utility companies generally own their lines up to the point where they enter your house.

Plan driveways and walks. Whenever possible, slope a driveway toward the street and make sure water entering the street can drain away easily. If you cannot do this, slope or crown the driveway slightly so water can drain to the edges. Or, plan for a drain in the middle of the slab. The large slab just outside the garage door is called the apron. Make sure it provides enough room for cars to maneuver, especially in the case of a two-car garage. The apron should be 1 inch below the garage floor to keep water out of the garage. Use expansion joints (also called isolation joints) wherever new concrete butts up against old concrete or another material. This allows the two to move separately. It is also a good idea to install an expansion joint every 15 feet or so in large slabs. Cut or strike control joints every 4 to 6 feet in walks or small slabs.

Additives for Concrete - Often, concrete lasts longer if you have it modified with an additive. Ask your building inspector and your concrete supplier if they recommend any of the following for your situation:

■ If you live in an area subject to severe freezing, consider using air-entrained concrete. This type of concrete is full of tiny bubbles that remain in the concrete after it has set. They enable the concrete to withstand the expansion and contraction that occurs during freeze-thaw cycles. You can order air-entrained concrete delivered in a truck or you can add an air-entraining agent when you mix it in a concrete mixer. But you cannot add the agent if you mix concrete by hand. When you add the agent, you will need to cut down on the amount of sand; check the instructions to find out what the ratio should be.

■ If you are pouring concrete on a cold day, consider adding calcium chloride to the mix. This will make the concrete set faster, which reduces the danger of cracking due to freezing. Be prepared to work fast.

■ If the weather is hot, it may make sense to add a retarding agent to keep the concrete from setting up too quickly.

■ In some areas and in some situations, you can eliminate the need for metal reinforcement by ordering fiberglass-reinforced concrete. Compare the price with the cost of wire mesh or reinforcing bar to see if this makes sense for your situation.

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