Page 348 - Construction Waterproofing Handbook
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8.8   CHAPTER EIGHT
                         All completed repairs or restoration work should be carefully documented. This docu-
                      mentation should be maintained by the building owner for future reference, should future
                      repair or warranty work be required. Once these remedial procedures are determined and
                      specifications are prepared, the next step in the restoration process is building cleaning.


          CLEANING

                      Existing structures have surface accumulations of airborne pollutants that must first be
                      removed to allow bonding of remedial waterproofing materials (Fig. 8.6). If surface pollu-
                      tants and dirt accumulations are considerable, it will be necessary to require building
                      cleaning before inspections. This provides adequate conditions to review present condi-
                      tions and make appropriate decisions (Fig. 8.7).
                         Besides aesthetic purposes, cleaning is a necessary part of building maintenance.
                      Maintenance cleaning ensures proper life-cycling and protection of building envelope
                      components against pollutant contamination.
                         Pollutants affect envelopes in two distinct manners. The first is by direct substrate dete-
                      rioration by pollutants, including salts, sulfites, and carbons that, when mixed with water,
                      form corrosive acids including sulfuric acid. These acids are carried into an envelope sys-
                      tem in liquid state. Acids attack not only in-place waterproofing systems but also structural
                      components, such as reinforcing steel or shelf angles.
                         The second pollutant deterioration is the slowing or halting of the natural breathing
                      process that allows entrapped moisture to escape. Pollutants carried deep into substrates by
                      water and moisture fill microscopic pores of envelope facades. If left unchecked, this collec-
                      tion will stop natural moisture escape that is necessary in substrates and will lead to damage
                      from freeze–thaw cycles, disbonding of coatings, and structural component deterioration.


























                            FIGURE 8.6 Chemical cleaning of substrate to adequately access substrate problems.
                            (Courtesy of American Building Restoration Products)
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