In the US every state, county, and city is centered around historical landmarks or buildings. From churches and schools, to municipal and government buildings, these structures typically represent the origin stories of the great cities we thrive in today.
Today the National Park Service in conjunction with the Secretary of the Interior, have provided guidelines and regulations as to how we should preserve these structures. Millions of dollars are spent annually on the restoration of buildings, while one of the most significant issues to is overlooked. Although these laws have been paramount in maintaining structural integrity, it is visually apparent that there is a lack of priority and knowledge for proper exterior cleaning of these highly revered structures.
According to the Standards for Rehabilitation Code 36 CFR Part 67, "The historic character of a property shall be retained and preserved. Each property shall be recognized as a physical record of its time, place, and use." Additionally it states that "Deteriorated historic features shall be repaired rather than replaced", and "Chemical or physical treatments, such as sandblasting, that cause damage to historic materials shall not be used. The surface cleaning of structures, if appropriate, shall be undertaken using the gentlest means possible." More often than not, historic structures of stone and masonry are either painted, or left untouched.
Overtime, the black staining often caused organic algae growth is accepted as an inevitable occurrence, or even that it "adds character". However, if not mitigated, the effect of these stains become more permanent. The organic growth is also one of the leading threats to the exterior, as the algae takes hold within the gaps in stone and masonry, promoting pre-mature cracking and deterioration.
Soft-Washing is the only proper method to completely restore any exterior to its optimal state, without the risk of damage from high pressure blasting and uneven striping. After an initial restoration, regular upkeep and service not only becomes easier/cheaper, but also ensures the maintains its intended appearance for years to come.
