How to Paint Brick Buildings.

Manufacturer and builder 4, 1870

In all our large cities, brick must continue to be the article most in use for constructing the walls of buildings, for the reason, if for no other, that the laws forbid the use of more combustible materials. The porous nature of this material and the mortar in which it is laid up is the only serious obstacle to its entire success as a building material possessing the grand requisites — beauty, durability, and economy.

The moisture of our winter atmosphere, with the changes of temperature, are continual causes of the disintegration of exterior brick surfaces. The water which during a thaw or winter rain-storm finds its way to all the exposed interstices of a wall, and the freezing temperature, which so quickly succeeds, destroy the cohesion of the particles. The great desideratum in this connection is some material which, being applied at not too great a cost, shall render the exposed portion of the surface entirely water-proof. Up to this time oil painting is the only process which has been in any degree auccessful; and this brings us hack to the important question, "How to paint exposed brick surfaces?" Pure white-lead is of all known pigments the most expensive and least durable for this purpose. It soon disintegrates under the influence of sunshine and storm, and loses whatever water-proof character it may have possessed when first applied. Therefore, it should not be used on brick-work except when a white surface is absolutely required.

It must be borne in mind that paints are durable mainly because of the water-proof quality of the oil in which they are used. The natural pigments — called ochres: or earth-paints - do not in any degree act upon the oil; while others, as white-lead and the chromates of lead, do affect the oil chemically, and impair in a measure its tenacity or water-proof quality. When work is painted simply to preserve it from the action of the weather, color and appearance are frequently unimportant considerations; and whatever material will most economically realize the desired result is most desirable. The deposits of ochre were deposited in ages long past; and it is reasonable to suppose that if these materials had been liable to change, the change would have taken place during the ages that they remained unappropriated to the use of man; but experience touches that they are not subject to those changes which belong to most of the artificial products used in painting.

These premises being admitted, it follows that the natural pigments are not only the most economical but the most durable for painting brick houses. It is an important question how and where time proper materials can be obtained with a fair prospect of tolerable if not absolute purity. As a rule, the respectable, established master-painters of the cities use the very best materials; but outside the cities the services of city skilled workmen are not readily obtainable, and time owner must avail himself of such labor as he can command. It is not safe to purchase a package of paint which does not entry with it the name of some respectable manufacturer as it guarantea of its quality.* The writer's experience demonstrates the fact that the most durable paint for brick-painting is a mixture of finely-ground French yellow ochre mixed with an equal quantity, by weight, of American white zinc. The color is a soft shade of buff, most pleasant to the eye, and permanent to the last degree both in color and material. Venetian red, an artificial ochre, or red oxide of iron, is in common use; but it does not hold oil like the yellow ochre, and makes a coating far less water-proof. It is a seemingly durable mint, because the stain which it imparts to a porous surface remains long after the oil has been washed away. It can not be used with white zinc, because of the unsuitable pink tint which it produces; and because this pigment, (Venetian red,) when tinted with white, becomes highly fugitive in color.

The condition of the wall is also very important in painting brick surfaces. The work should be done in dry, warm weather, when the moisture which bricks absorb during the winter and spring seasons has dried out; otherwise the paint will not be apt to adhere tenaciously, but will scale or peel off. The joints in the stone coping on brick walls require constant looking after. These should be made absolutely impervious to water by the application of a mass of soft paint-skins both on the top and edges; and when this hardens to the point of cracking, it should be removed and renewed. Mortar and cement for such purposes are altogether useless. The joint, too, between the wall and the coping underneath should be well filled wills paint-skins before painting; for, no matter how water-proof the surface may be, if the water be allowed to percolate through the joints in the coping, the integrity of the wall will be destroyed.

A paint, into which carbolic acid enters as one of the component parts, has recently been discovered, and some exposed brick walls of censidereble extent have been coated with it. It is now undergoing the test of time and atmospheric changes. The inventor has not a shadow of doubt of its entire success; but declines to put the material upon the market, until by actual trial its durability shall have been demonstrated. If the hopes of the inventor should be realized, the question, "How to paint brick houses?" will receive a new and satisfactory solution. In the mean time, it will be well to bear in mind the fact that good results in painting are possible only by the use of good materials. The best of the kind are always the cheapest.

Ei kommentteja :