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There are many reasons for cleaning historic masonry buildings.
The most common substances removed are organic growth, such as mold and lichens, and non-historic paint.
Masonry should always be cleaned using the gentlest means possible.
Abrasive methods, such as sandblasting, should never be used to clean any substance from a historic masonry building.
Ironically, improper abrasive techniques for the removal of biological growth (or anything else) can worsen water problems, accelerating the growth of unsightly and damaging organic matter.
Because improper cleaning can cause irreversible damage, property owners should weigh benefits and risks with a historic architect and masonry restoration contractor.
Experienced contractors can safely remove non-historic paint with a chemical paint stripper – and organic growth with a bioside, a chemical formulated to kill biological growth.
Treanor Architects specified a bioside for the safe and effective removal of a black lichen at the Philip Hardware Building in Hays, Kansas (see photos below).
Before the building was cleaned, contractors addressed any sources of moisture that had sustained the organism. |
