Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, September 3, 1995 TAG: 9509070001
SECTION: HOMES PAGE: D-2 EDITION: METRO
SOURCE: GENE AUSTIN KNIGHT-RIDDER NEWSPAPERS
DATELINE: LENGTH: Medium
Following are some guidelines:
If a sizable chunk has broken off the corner of a sidewalk slab or driveway, which are usually about four inches thick, concrete mix is the best repair product to replace it. Concrete mix is sold in 60-pound bags at home centers and hardware stores, usually priced at less than $3 per bag. The mix contains small pieces of gravel or aggregate that give it extra strength. A rule of thumb: Concrete mix, also called gravel mix, should be used for repairs more than two inches deep.
Like other dry repair products, concrete mix is blended with some water immediately before use. A metal wheelbarrow or plastic tub makes a good container for mixing, and a garden hoe is a good mixing tool.
Do-it-yourselfers with special needs can also find fast-setting concrete mixes, which are fine for setting posts or repairing areas that must be used quickly.
Sand mix, generally sold in 60-pound bags at less than $3 per bag, is a good choice for patches ranging from about 1/2 inch to less than two inches thick. Sand mix contains no gravel and makes a smoother blend than concrete mix. It is fine for filling holes, resurfacing beat-up slabs, and filling sizable cracks.
If a repair doesn't fit either of the above situations, do-it-yourselfers can choose from many specialized products.
Examples of situations where specialized products are needed are shallow surface damage and small cracks.
One company, Macklanburg-Duncan, of Oklahoma City, makes a line of specialized concrete-repair products under the brand name Mr. Mac's. Some of the Mr. Mac's products contain polymer modifier to give them more flexibility than conventional concrete mix or sand mix.
Examples of Mr. Mac's products are Concrete Fix, for repairing shallow damage or patching small areas and cracks; Concrete Resurfacer, which can be spread in a layer as thin as 1/32 inch to restore a pitted or flaked surface or fill low spots; and several types of crack fillers. For more information on Mr. Mac's products, call 800-348-3571.
Another company with a line of specialized repair products for patching, rebuilding and resurfacing concrete is Abatron Inc., of Gilberts, Ill. (800-445-1754). These products include Abocrete, for repairing and rebuilding deteriorated surfaces; Aboweld, a patcher for vertical surfaces that won't slump or sag; and Abocoat, a roll-on resurfacer.
Many home centers and hardware stores also sell special thin-layer patchers such as Amstone's Top 'n Bond. Top 'n Bond can be troweled in thicknesses of 1/2 inch or less, or brushed on in an extra-thin layer to resurface unsightly slabs. Top 'n Bond is sold in 40-pound bags and 10-pound tubs.
Small cracks in concrete are a special problem that can be dealt with in a variety of ways, but lasting repairs are difficult because cracks are generally caused by underlying problems such as tree roots or earth movement. Don't be surprised if a small crack reopens in time, no matter what product is used.
In addition to dry patchers that are mixed with water and forced into a crack with a trowel, there are liquid patchers sold in squeeze bottles and paste-type patchers sold in caulking-gun cartridges. Caulk-type and liquid patchers are difficult to beat for convenience. Many of these patchers contain vinyl, latex or other additives to increase flexibility and improve adhesion with the area being patched.
Before buying any concrete-repair product, read the directions on the container to make sure the product suits the job to be done. Carefully follow the patching procedure outlined in the directions. For example, if a narrow but deep crack is being repaired, the crack might need to be filled to close to the surface with sand or another filler material.
Probably the best single tip for successful concrete repair is to clean the surface thoroughly before attempting the repair. Chip away any loose material and brush off or vacuum up crumbled concrete and dirt, since the patcher needs a firm, clean surface for good adhesion.
(Readers' questions and comments are welcome and should be sent to Gene Austin, the Philadelphia Inquirer, Box 8263, Philadelphia, Pa. 19101. Questions cannot be answered personally.)
by CNB