Living in New York City can be something of a dirty job. Thanks to the hustle and bustle of big city living, the task of cleaning off months (or years) of accumulated grime and dirt from the exterior of a residential building takes much more than just a scrub-brush and a bottle of Windex; it requires professional help. The task is not just a labor-intensive job—it also calls for extensive knowledge of building materials, cleaning products and cleaning methods.
Removing the Dirt
For residents of co-ops and condos, knowing when, how and why or why not to have the exterior of their building cleaned could be a matter of dollars and cents but it also should be about what makes common sense. Most buildings would find it unnecessary to clean their building’s entire exterior each month, but some might want it done biannually, while others could allow the façade to darken for years before tending to it. It all really depends upon a building community’s perceptions, needs and budget.
Knowing the causes of exterior sediment and the cleaning methods used to deal with it can enable residents to take a realistic approach to the problem of keeping their building’s façade looking sharp. It’s hard to say what creates the most stains and grime on buildings: air pollution, dust from building equipment, car exhaust, subway soot...the list goes on and on. Facades are also soiled by atmospheric conditions like acid rain, and the buildup of dirt on a building over time can dull architectural details and lessen the overall beauty of the structure.
“Before 1930, they were burning coal in all these buildings, and the air quality was much worse. It stained the buildings,” says Andrew Wist, president of Standard Waterproofing in the Bronx. “Today, traffic pollution still causes carbon stains on buildings.”
Aside from looking terrible, some long-term problems may be associated with letting dirt and grime accumulate on your building. That dirt can create a sealing barrier that won’t allow the building exterior to “breathe,” and thus, cause problems such as water retention. Also, calcium and sulfates left on a building facade create acidic conditions and salts which can penetrate and cause deterioration to the masonry and underlying materials.