Hydrated lime or lime putty can be blended with water to produce whitewash. Other possible additives in these mixes include molasses, alum, milk, salt, glue, white cement or pigments, depending on the final properties desired.
Whitewash is an inexpensive coating that historically has been used to decorate, protect and sanitize a wide range of materials. Whitewash typically has a bright white color. However, lime-fast pigments, can be added to provide a broad range of colors. The principal ingredients in whitewash are hydrated lime and water. Hydrated lime absorbs carbon dioxide from the air to convert back to limestone. This reaction provides a protective layer over the whitewashed surface. Finally, the pH of hydrated lime helps to sanitize surfaces.
As well as being inexpensive to produce, whitewash has many environmentally friendly formulations. It has been used on both wood and masonry surfaces in building construction. Whitewash is used to reduce odors and provide more sanitary conditions in dairy barns, poultry houses, stables, kennels or similar buildings. The white color of the coating can also minimize the absorption of heat. Whitewashing trees can protect them from frost damage by keeping them cool enough to remain dormant. In southern climates, whitewash can also be applied on roof tiles to prevent the absorption of heat.
Graymont Spray Lime is a dolomitic hydrated-lime product that meets the criteria of ASTM C206 for Finishing Hydrated Lime. The fine particle size of this product contributes to excellent dispersal and coverage in whitewash formulations. Graymont Spray Lime is available in 50-lb. (22.5-kg) bags.