Specifications include, but are not limited to: a. Section includes cleaning the following: i. Unit masonry surfaces ii. Cast stone surfaces installed on exterior windows, pilasters and walls. 1.2. DEFINITIONS a. Low-Pressure Spray: 100 to 400 psi; 4 to 6 gpm b. Medium-Pressure Spray: 400 to 800 psi; 4 to 6 gpm 1.3. PREINSTALLATION MEETINGS a. Pre-installation Conference: Conduct conference at Project site. i. Review methods and procedures related to cleaning masonry and cast stone including, but not limited to the following: • Verify masonry-cleaning equipment and facilities needed to make progress and avoid delays. • Materials, material application, and sequencing. • Cleaning program. • Coordination with building occupants. 1.4. SEQUENCING AND SCHEDULING a. Work Sequence: Perform masonry-cleaning work in the following sequence: i. Remove plant growth. ii. Inspect for open mortar joints. Where repairs are required, delay further cleaning work until after repairs are completed, cured, and dried to prevent the intrusion of water and other cleaning materials into the wall. iii. Remove paint. iv. Clean masonry surfaces. v. Where water repellents are to be used on or near masonry, delay application of these chemicals until after cleaning. b. If scaffolding is required, patch anchor holes used to attach scaffolding. Patch holes in masonry units according to masonry repair Sections. Patch holes in mortar joints according to masonry repointing Sections. 2.1. CLEANING MATERIALS a. Water: Potable. b. Detergent Solutions, Job Mixed: Solution prepared by mixing two cups of tetrasodium pyrophosphate (TSPP), ½ cup of laundry detergent, and 20 quarts of hot water for every five gallon of solution required. c. Mold, mildew, and algae remover, job mixed: Solution prepared by mixing two cups of tetrasodium pyrophosphate (TSPP), five quarts of five percent sodium hypochlorite (bleach), and 15 quarts of hot water for every five gallon of solution required.