Basics of Repairing Masonry
Homeowner repair of concrete and masonry was once nearly impossible. Concrete, of itself, has no adhesive properties and will not adhere to old concrete when applied in thin layers or patches. Plus, masonry that is damaged --a broken edge on a step, for example -- will usually be soiled with dirt and the dirt will interfere with the patching process by causing a poor bond between the old concrete and the new patching material. Also, cement and sand were once packaged in large quantities for professional use only: if one n you needed 10 lbs. of cement to make a repair, what can you do with 84 lbs. of cement leftovers from a 94-lb. bag? Too often, the leftover cement would harden in the bag as it absorbed moisture from the air and be wasted.

Today, packaged masonry and concrete repair products contain all the needed ingredients, all carefully weighed and blended to the correct proportions. Latex bonding agents are included in the mix, or packaged in a separate can in a kit, and the bonding agents make the concrete patcher sticky enough to bond to the old concrete. And, the patching kit is packaged in a plastic pail that serves as a mixing pail and can be discarded in the trash without cleaning when the job is finished.

Also available are bagged products that have brand names such as Sakrete and Quikcrete, which contain cement, sand, and gravel mixed in the proper proportion and intended to eliminate the mess of home mixing. All you have to add is water: in fact, if you are pouring concrete piers or supporting fence posts below ground, you can dump in many of these products dry and let the ground moisture set the material, or pour a little water in the hole atop of the dry mix. If you must mix the concrete patch product with water, pour the dry mix in a wheelbarrow or a 5-gallon plastic pail and mix it with a garden hoe or trowel. Or, buy a mixing bit from a wallboard tool store and chuck the mixing bit into a 1/2 in. drill to mix concrete or asphalt patchers.

If you are building a large concrete project, such as a driveway or patio slab, you may want to rent a cement mixer and do your own mixing. The alternative to using a portable mixer would be to order ready-mix concrete delivered by a truck. Before making the decision to mix your own concrete, you should consider the advantages of having the material mixed in a truck, or in transit. The truck mix will be properly proportioned per the amount of Portland cement, sand and gravel. It will have the proper "slump" or consistency, and there is no mess from on-site mixing. And, the truck will direct a chute over the formed project and place the concrete for you. This placement is no small thing: We are talking of mixing, moving, and spreading tons of concrete. That's a lot of work to save a few bucks.

If you decide to mix your own concrete, you can buy cement in 94-pound bags (One cubic foot), and buy sand in bags or in bulk from masonry supply firms or gravel dealers. If you choose to do so, the mixing formula for concrete is easy as 1-2-3: Mix 1 part of Portland cement, 2 parts sand and 3 parts of gravel, with enough water to make a firm mudball when you grip a handful (note that the consistency of the mix will vary: more water will be needed for spreading a concrete slab, or for working in hot weather when a thick dry mix will set quickly and be difficult to trowel). Always add water sparingly: keep in mind that bulk sand may have a high water content, so less water will be required than with dry sand.

Masonry patching requires the appropriate patch material -- depending on whether you are patching a hole or a crack in masonry -- plus a stick or mixing bit (for your drill) if mixing will be required. For caulk-tube repair products, you will need a caulk gun for applying the patcher, a razor knife for cutting the nozzle tip, and a popsicle stick or plastic spoon for smoothing the patch material. You will also need the appropriate solvent: water for cleaning up latex patchers and mineral spirits for cleaning up asphaltic or oil-base products. You will also need a selection of small paint scrapers or trowels to apply and smooth holes or patches in damaged concrete.

Written by Gary Branson.
Reprinted with permission. Copyright HouseNet, Inc.

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