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Newman Center: Masonry Repair <br />SB Project No. 116-132 <br />C. Use only those cleaning methods indicated for each concrete material and location. <br />1. Brushes: Do not use wire brushes. <br />2. Spray Equipment: Use spray equipment that provides controlled application at volume and <br />pressure indicated, measured at nozzle. Adjust pressure and volume to ensure that cleaning <br />methods do not damage surfaces, including joints. Use spray equipment for wetting and <br />rinsing operations only, and do not damage surfaces, including joints. <br />a. Equip units with pressure gages. <br />b. For water -spray application, use fan -shaped spray that disperses water at an angle of 25 <br />to 50 degrees at 50 psi. <br />C. For cleaner spray application, use low-pressure tank or pump suitable for cleaner <br />indicated and equipped with a nozzle having a cone -shaped spray. <br />D. Perform each cleaning method indicated in a manner that results in uniform coverage of all <br />surfaces, including corners, moldings, and interstices, and that produces an even effect without <br />streaking or damaging masonry, stone, or concrete surfaces. Keep wall wet below area being <br />cleaned to prevent streaking from runoff. <br />E. Perform additional general cleaning, paint and stain removal, and spot cleaning of small areas <br />that are noticeably different when viewed according to the "Cleaning Appearance Standard" <br />Paragraph, so that cleaned surfaces blend smoothly into surrounding areas. <br />Water Application Methods: <br />1. Water -Soak Application: Soak concrete surfaces by applying water continuously and <br />uniformly to limited area for time indicated. Apply water at low pressures and low volumes in <br />multiple fine sprays using perforated hoses or multiple spray nozzles. Erect a protective <br />enclosure constructed of polyethylene sheeting to cover area being sprayed. <br />2. Water -Spray Application Method: Unless otherwise indicated, hold spray nozzle at least 6 <br />inches from concrete surface and apply water in horizontal back -and -forth sweeping motion, <br />overlapping previous strokes to produce uniform coverage.. <br />G. Cleaner Application Methods: Apply cleaners to concrete surfaces according to cleaner <br />manufacturer's written instructions. Do not spray -apply at pressures exceeding 50 psi. Do not <br />allow cleaner to remain on surface for periods longer than those indicated or recommended in <br />writing by manufacturer. <br />H. Rinse off residue and soil by working upward from bottom to top of each treated area at each <br />stage or scaffold setting. Periodically during each rinse, test pH of rinse water running off of <br />cleaned area to determine that cleaner is completely removed. <br />After cleaning is complete, remove protection no longer required. Remove any tape and adhesive <br />marks. <br />3.4 PRELIMINARY CLEANING <br />A. Removing Plant Growth: Completely remove visible vine and shrub growth and moss from <br />concrete surfaces. Remove plants, creepers, and vegetation by cutting at roots and allow <br />remaining growth to dry as long as possible before removal. Remove loose soil and plant debris <br />from open joints to whatever depth they occur. <br />B. Preliminary Cleaning: Before beginning general cleaning, remove extraneous substances that are <br />resistant to planned cleaning methods. Extraneous substances include paint, calking, asphalt, <br />and tar. <br />COIN CRETE CL EAN W G Page i 03 01 30 - 4 <br />