Copyright Goodheart-Willcox Co., Inc. Chapter 12 Laying Brick 253 Cleaning Light Colored Brick Light colored brick includes buff, gray, speck, and pink. Light brick is more likely to be burned by acid than darker brick. Therefore, do not use acid except in extreme cases. The procedure for cleaning light P R O C E D U R E Cleaning Dark Brick without Acid 1. When the mortar is thoroughly set and cured, begin the cleaning operation. 2. Remove large particles of mortar with wooden paddles or scrapers before wetting the wall. A chisel or wire brush might be necessary. 3. Saturate the wall with clean water and flush away all loose mortar and dirt. 4. Scrub down the wall with a solution of 1/2 cup of trisodium phosphate and 1/2 cup of household detergent dissolved in one gallon of clean water. Use a stiff fiber brush. 5. Rinse off all cleaning solution and mortar particles using clean water under pressure. Acid Cleaning of Dark Brick 1. When the mortar is thoroughly set and cured, begin the cleaning operation. 2. Remove large particles of mortar with wooden paddles or scrapers before wetting the wall. A chisel or wire brush might be necessary. 3. Saturate the wall with clean water and flush away all loose mortar and dirt. 4. Use a clean, stain-free commercial grade of hydrochloric (muriatic) acid. Mix one part of acid to nine parts water in a nonmetallic container. Use a long handled fiber brush to scrub the wall surface. 5. Keep the area not being cleaned flushed free of acid and dissolved mortar. This scum, if allowed to dry, may be impossible to remove later. 6. Scrub the brick, not the mortar joints. Do not use metal tools. Clean only a small area at a time. 7. Rinse the wall thoroughly with plenty of clean water while it is still wet from scrubbing with the acid. Safety Note Before using muriatic acid, read the manufacturer’s instructions and the SDS document. Follow manufacturer’s specifications for mixing, applying, cleaning, and disposing of leftover solution. Wear appropriate PPE, safety glasses, approved rubber gloves, protective boots, and clothing as specified. When mixing, pour the acid into the water, not the water into the acid! colored brick without acid is the same as the procedure for dark colored brick. To acid clean light colored brick, follow steps 1–3 of the procedure for acid cleaning of dark brick. Then mix one part acid with 15 parts water and scrub the wall with a fiber brush. Rinse the wall well with clear water. Neutralize the acid wash with a solution of potassium or sodium hydroxide, consisting of 1/2 lb hydroxide to 1 qt of water (2 lb/gal). Allow this solution to remain on the wall for two or three days before washing again with clear water. Cleaning Failures Cleaning failures generally fall into one of three categories:■ ■ Failure to thoroughly saturate the brick masonry surface with water before and after application of chemical or detergent cleaning solutions. Saturation of the surface prior to cleaning reduces the absorption rate, permitting the cleaning solution to stay on the surface rather than be absorbed. ■ ■ Failure to properly use chemical cleaning solutions. Improperly mixed or overly concentrated acid solutions can etch or wash out cementitious materials from the mortar joints. ■ ■ Failure to protect windows, doors, and trim. Many cleaning agents, particularly acid solutions, have a corrosive effect on metal. If permitted to come in contact with metal frames, the solutions may cause pitting of the metal or staining of the masonry surface and trim materials, such as limestone and cast stone. If mortar is on window glass, metal tools or strong chemicals can scratch or etch the glass. Sand in the mortar can also scratch the glass. Pressurized Water Cleaning A pressurized power washer is a valuable piece of equip- ment used to reduce labor and costs. See Figure 12-68. However, because of the extreme pressures that these machines achieve, they can damage masonry and cause injuries to workers who are operating the equipment or who are in close proximity of the spray. Prior to cleaning masonry with a power washer, read the manufacturer’s specifications and instruction man- uals. Follow procedures for hand cleaning brick as Trade Tip Use the highest grade acid available. It should be free of any yellow or brown discoloration.