HOME CARE: Concrete And Masonry Repairs

                       CONCRETE AND MASONRY REPAIRS

When we speak of concrete and masonry repairs, we are referring to those parts of the house which are constructed of brick, stone, cement block, tile and all cementitious products. As a rule, basement and celler floors will be made of concrete. The walls will be made of cement block, brick or poured concrete, and very often the steps and terraces are made of masonry materials.

Masonry does not have the ability to expand and contract to any great degree without cracking, or fracturing, and you will often see brick steps which are badly broken up and loosened, because water has gotten beneath them, frozen, and forced the bricks apart. You will also see cracks in a basement floor which are caused by slight settling of the walls or by the washing-out of the fill underneath the floor. We will take all of the concrete and masonry portions of the house, one at a time, and try to explain exactly how they should be kept in repair and how the repair can be most easily done by the homeowner.

The basement floor of a house is usually made by laying several inches of cinders or crushed stone and rolling them down hard. A coat of concrete, from 2 to 3 inches thick, is then spread over the bed and troweled to a finish. Cracks in a basement floor which admit water into the basement, are usually found where the floor meets the basement walls. One of the best remedies for this condition is to mix a small amount of cement and sand in proportion of two of sand to one of cement, making the mix about the consistency of pea soup; wet the cracks very thoroughly; allow them to dry so that there is no free water standing in the crack; then brush in the mixture. The crack should be cemented to the very top and then smoothed off.

The joint where basement floor meets foundation walls is liable to leak. This can be cured by filling it with a cement paste.

Frequently we see cracks running right across the basement floor. This may be caused by expansion and contraction or it may be caused by a slight settlement of the foundation walls. The best remedy for this condition is to brush out the crack so that all loose particles are removed, wet the crack thoroughly, and trowel in a mixture of prepared concrete patching material which can be found in almost any hardware or building supply store.

On some occasions a section of the floor will break up into several pieces and sink below a level of the rest of the surface. This is always caused by the settling or washing out of the fill under the floor and there is only one remedy for it. With a heavy sledge or maul, the floor should be broken up and the pieces of concrete flooring removed. The breaking-up should continue until you can see that the edge of the hole is over solid fill. Damp sand should be thrown in and tamped down solidly until the fill is even with the surrounding edge. Then fresh concrete, composed of a mixture of one of cement, two of sand, and three of crushed stone, should be thrown in, tamped and floated to a finish corresponding with the firm edges.

The above operation, however, does not quite finish this job. The fresh concrete should be covered with old burlap bags or an old blanket, and this should be kept dampened for at least five days before it is removed. At the end of that time the patch will have set up hard and be ready to walk on without any danger of fracture.

Cracks in brick basement or cellar walls should be treated in exactly the same manner as recommended for the treatment of exterior brick walls. In other words, all loose mortar cracks should be cut out, the brick well dampened and fresh mortar trowelled in.

If one brick is permitted to remain loose, the bricks on either side will follow suit rapidly. All bricks must be kept solidly in place if you want to avoid complete disintegration.

Cracks in cement blocks should be treated in exactly the same way, taking great care that the dry area around the new joint has been well wetted before forcing in the new mixture.

Repairs to brick steps or terraces must necessarily be done with great care, because when you are making a repair to a wall it is simply standing there and is not subject to contusions as are brick steps or platforms. Practically everyone who has lived in a house has seen heavy trunks or crates dumped on the brick steps with very bad effect. When a brick has been loosened there is only one proper way in which to treat it and that is to lift it out entirely. Take a very sharp cold chisel and a hammer and chip off all of the old bonding material. This should not only be taken off the brick that has been removed, but it must also be taken off the edges of the adjacent bricks and out of the space from which the brick has been removed. All surrounding surfaces must then be wet, a fresh bed of cement laid and the brick reset in place so that edges and surface match up with the adjoining area. Then the joint should be trowelled to correspond with the other work and the repair kept covered with damp cloths for five days. It should be noted, that to step on a freshly set brick before that length of time, will loosen it and make the job worthless. It should also be noted that in repairing steps, platforms, or terraces, that cement and sand mix should be used instead of mortar.

All amateur masons should remember the necessity of trying to "key-in" mortar or cement joints. It should be perfectly obvious to anyone that if you have a crack in a wall or floor, and the exposed space is wider than the inside portion of the crack, that providing the bond is not very good, the fill is liable to fall out of, or be forced out of the crack. On the other hand, if you manage to make a key by having the inside portion larger than the wide surface, nothing can ever force the fill out of that crack. It will have to be chiselled out.

While it does not come directly under the heading of Masonry and Repairs, something should be said at this point about discoloration of brickwork. You often see a good-looking brickhouse, the walls of which are badly discolored with patches of a white salty-looking stain. This is known as effluorescence and is brought about by the fact that soluble salts which are found in cement and mortar are dissolved by dampness and work to the surface, where they dry and thus show the salt-like patch. A sure cure for this is to wash off the wall with a mixture of water and tri-sodium phosphate. It is best to do this after the wall has been dry for several days. If patches of effluorescence continue to appear after this treatment, it will be necessary to clean the wall as above and then, in addition, give it a coat of penetrating, colorless waterproofing compound. This is an amber-colored emulsion which will sink into the pores of the brick and seal them so that no further effluorescence can work to the surface.

The average person will undertake to cut a board in half or to paint a door, but they will invariably shy away from anything that involves brick-work,concreteor masonry, because they think that it involves a lot of knowledge and considerable skill. Nothing could be farther from the truth. All masonry work consists simply of the ability to bond together bricks or stones with mortar or cement, or to pour concrete into a mold and level it off. We naturally are not referring to the building of arches or of intricate brick work, or to the building of forms for heavy structural jobs. We refer simply to the every-day patching and repairing of masonry as it may be encountered in the average small home.

When there is a loose brick, a crack in a concrete wall, an open fissure in a cement floor, or a leaking joint in a stone wall, we insist that the average homeowner can take care of the difficulty if he will just study the defect, remember what he has been told, and take his time in making the repair.

Always remember that dry masonry is absorbent, and that no repair will be worthwhile unless the area around the patch or the new work has been wetted.

Around every house, there are probably a dozen places where a clean-cut job of masonry could be done which would eliminate repeated repairs to woodwork. There are many porch steps, many back-entrances and many wood platforms which could well be replaced by a neat mat of concrete. There is nothing which would prevent a homeowner from making a simple wooden form, three inches high, at the bottom of his steps, and filling it with concrete so that he had a permanent landing. There is nothing so complicated about setting up a form composed of three or four steps, which he could fill with concrete, and thus have a permanent set of steps. As a matter of fact, if he were to remove the treads, he would already have a form ready to fill with very little alteration. He might have to allow for a change in levels of course, but beyond that there would be little to worry about.

There is a permanence about cement and masonry work which is very satisfying. We have seen people start by laying a patch of cement under the down-spouts from the roof, where they emptied on the lawn, and cut away the grass; and who ended up by making wood forms with which they edged their driveway and paths, and so produced a permanent labor-saving edge. We have also seen field stone walls erected by amateur mechanics, which were as good as any to be found in New England. It may be true that when they finished a fifty or sixty foot run, that they liked the last half of the wall so well that they went back and tore down the first half, but the net result was a good workmanlike job which will stand up.

There is nothing about masonry or concrete repair work that should bother anyone of average intelligence, and there is always the saving thought that if it does not work out, you can do it over again. If you adhere to the formulas for mixing which have been given, and follow the procedures recommended, you cannot help but produce at least a decent repair job. There is also the thought, that practice makes perfect; and it applies particularly to masonry. With every job you attempt, your technique will improve.

The present trend toward living in the country has created quite a demand for many of the small advantages which are not found in the ready built house, and there is no place where home-made jobs of concrete could be used to better advantage. As an example of what the homeowner can do for himself and his house we would suggest the following.

Forms for concrete flags, bases, steps or platforms are easy to construct and fill. Forms should be braced to avoid distortion.

Take a piece of three by one inch finishing strip, and cut it up into four sections, each one two feet long. Nail these together so as to form a square box without either top or bottom; and tack another piece across the top diagonally so as to prevent the box from warping out of square. Mix up a batch of concrete using three parts of crushed stone or gravel, two parts of sand and one part of portland cement. With just enough water to make a good stiff mixture. Fill the form and allow it to set for five days. At the end of that time you can knock off the form and you will have a heavy concrete unit which may be used to advantage as a base for a sun-dial or other lawn ornaments. If you manage to get through this simple operation, you will be well under way to knowing how to handle concrete.

Masonry strikes the amateur with far greater force than it does the professional builder. At the same time, the person who knows nothing about masonry, is quick to detect the difference between good and bad masonry work. The job above is a masterpiece of the stone-masons art. Fine joining and fitting will make repairs unnecessary for many years

SOURCE: How to take care of your home by Douglas Tuomey