A wash composed of lime, salt, and fine sand or wood-ashes, put on in the ordinary way of whitewash, renders a shingle roof fifty-fold more safe against fire from falling cinders, in case of fire in the vicinity. It has also a preserving influence against the effect of the weather; the older and more weather-beaten the shingles, the more benefit derived. Such shingles are generally more or less warped, rough, and cracked. The application of wash, by washing the upper surface, restores them to their original or firm form, thereby closing the space between the shingles; and the lime and sand, by filling up the cracks, prevent its warping. By the addition of a small quantity of lamp-black, the wash may be made of the same color as old shingles, and thus the offensive glare of a whitewashed roof is removed.