Like people, buildings age. Even under the best of atmospheric conditions, dust, dirt and grime accumulate, changing a building’s appearance over time. Often it’s not until a building’s façade is cleaned that one notices how it was dirty to begin with. In some cases the patina that grows on a masonry façade can even enhance a building’s appearance. Consider the many fine, old, iconic buildings in major cities around the world. A postcard would look a lot different if these buildings were cleaned regularly!

How Often to Clean? 

So the question arises: how much, and how often to clean your building’s façade?

“That often depends on the owner,” says Mark Rashkow, partner and founder of Ace of Spray, a pressure washing company with three offices located in Chicago, Milwaukee and Central Illinois. “People will argue that dirt and grime can hide defects, but they also accelerate aging,” bringing on additional problems. “Some owners clean their façades on an annual basis, others wait several years. Again, it depends on the owner and what standard they want to maintain.”

How often a building should be cleaned has a lot to do with the actual physical location of a property relative to various sources of grime. According to an article entitled ‘Façade Cleaning: For More Than Appearance’s Sake,’ published by Hoffmann Architects in Journal, “Not all building façades warrant the same amount of attention. A building’s location, function and geographic and atmospheric conditions all play roles in determining the level of cleaning effort necessary to achieve the desired appearance.”

“There is a natural buildup of atmospheric pollutants, which develops on surfaces over time,” explains Rashkow. “How high the concentration of that content is in the air is what dictates how quickly it builds up on your building. A building near a highway where there are obviously higher concentrations of pollutants from cars trucks, etc., will cause grime to develop more quickly than a building in, say, a more isolated suburban setting. On the other hand, buildings in that suburban setting may be exposed to more moisture, which can lead to mildew – especially when coupled with landscaping elements in close proximity.”

Tom DeFrancesco, vice president of J&T Mobile Wash, specialists in both building and vehicle washing, with locations in New Jersey and New York, confirms confirms Rashkow’s findings, noting that these conditions are normal for urbanized and suburbanized areas in the colder, wetter parts of the United States, such as the Northeast and Midwest. 

“Emissions are the primary source of façade grime in urban environments,” he says. “It’s especially tough on limestone.” Limestone was the primary façade material used in the second half of the 19th century, and is commonly found in major cities in the Northeast and Midwest. The effect of emissions-based pollution on limestone has been known for decades. 

In more suburban areas, “The most common types of stain and grime found on New Jersey buildings are algae,” says John Doherty, president of Garden State Powerwash and roof cleaning in Manalapan. “So the cause is environmental. You see it more on the north side of buildings because that side gets the least amount of sun.”

Colm Fidgeon, president of Precision Power Wash in Somerdale, agrees with Doherty that environmental pollutants is the number one source of most grime and grit on New Jersey buildings. “Mother Nature is the problem,” he says. “It causes all of the mold and algae, especially on roofs. I see lots of algae, the black streaks on New Jersey rooftops.”

“Everything depends on where your building is located,” says Dave Scaturro, sales and marketing director for Alpine Painting & Sandblasting Contractors in Paterson. “For example, if you are located in the woods and there are a lot of trees and heavy growth around, you’re going to get a lot of mold and mildew. If you have a lot of steady rain and you don’t have the proper eaves protecting your building, then you are much more likely to get that green, discolored look on the siding or trim of your building. If you are in the city and you get lots of cars driving by, you’re going to get a lot of carbon staining. We see more mold and mildew than carbon, but it’s completely dependent on the location of the building.”

According to DeFrancesco, “One of the interesting side benefits of regular cleaning in suburban settings is that “when a job is done properly, with proper detergent, we are actually killing the mold spores. It will come back though, but less often. When you see it returning is when another cleaning should be done. Don’t wait till it’s completely covered.”

Cleaning Methods

According to Hoffmann Architects in their article in Journal, there are four basic categories of façade cleaning techniques: “Chemical, non-chemical, abrasive, and those that require a combination of these methods. For example, though a masonry façade cleaning project may partially succeed with a non-chemical water soaking procedure to loosen dirt and wash it away, it may be necessary to supplement this method with an appropriate cleaning agent (chemical) to treat areas with heavy stains.” It should be noted that in the façade cleaning business, ‘chemical’ can mean anything from mild detergent to sulfuric acid.

The most common and widely-used cleaning technique is pressure washing, which is typically non-chemical. “We can dial up or down,” says DeFrancesco of the water pressure applied to literally blast crud off the surface of bricks, stone, and so forth. Pressure can be adjusted up to approximately 2,900 pounds per square inch, depending on the extent of staining and the underlying building material. “We use very hot water pressure washers,” adds Rashkow. “Ninety-eight percent of our jobs are chemical free, which is the case for most professional washers.”

When chemicals are needed, “There are specific detergents for specific surfaces, whether they be granite or limestone or stucco,” says Rashkow. “It’s a very big business.” Much depends on the type of surface. “As far as limestone,” says DeFrancesco, “we use special chemical cleaners and lower pressure, but the same high temp of 200 degrees.” This method is knows as a ‘soft-clean’ system with detergents.

According to the pros, façade cleaning can take anywhere from a couple of days to a couple of months, depending on the scope of the job and the size of the building. For a ten-story building in a denser urban area, a cleaning job could take as much a two months. For a small suburban property, it might only take one day. 

Training, Precautions, and Permits

“If it’s relatively tall, a building has to be encapsulated in scaffolding where everything stays contained within the cleaning area itself,” says DeFrancesco. “If it’s a lower-rise building – say up to three stories – we do it with a minimal pedestrian impact time, like at night or early in the morning. We rope everything off and have flaggers to direct the foot traffic. All the workers wear full face masks or hazmat suits when necessary, depending on what chemicals we might be using.”

The pros point out that in some areas when chemicals are used, they may have to take steps to reclaim the contaminated runoff water. “If we are using chemicals, we have to recycle all water,” says one exterior contractor. “We make sure it doesn’t go down the drain,” thereby contaminating local water tables. “If a town has water ban (as Stamford, Connecticut did last summer), we may not be able to do a job,” because generally his company uses their own equipment but taps into the town’s water supply.

Rashkow recommends that “you be aware of your surrounding, neighboring buildings, pedestrian traffic, and vehicles on the street. There are at times permit requirements, and you may have to encapsulate a building before you can use chemicals. You must control the inclusion of chemicals in your estimates because they are very expensive – as is the cost of encapsulation – and the chemicals can be dangerous. Detergents and chemicals are required to be recaptured under many local ‘green’ laws.”

The cleaning pros we spoke to all report sending their employees for regular training and refresher courses. “A lot of training is required,” says Rashkow. “We don’t allow anyone to power wash a façade until they have been with us for a year, and then it’s still monitored. All training is done within the company.” DeFrancesco concurs, adding that “training is very important. Our professional organization provides training for our employees.” These courses are available on a regular basis. “We send our guys for safety training every year, and to qualify for recycling procedures.”

Insurances and Licenses

All companies performing façade cleaning services carry insurance. Insurance coverage is a general policy, not specific to any particular job. It is part of a larger policy of business insurance, according to all three experts quoted here. As far as licenses are concerned, that depends on location. According to Rashkow, Illinois does not require specific licensing, either. DeFrancesco says New York does not require licensing, but New Jersey does. Other considerations are ‘green laws’ mandating particular treatment and disposal of chemical-containing water or other materials, and whether a building has been declared a landmark. 

Industry experts contacted for this article all agreed that picking the right contractor is one of the most important aspects of undertaking an exterior cleaning of a residential building. A board should truly vet the contractor before hiring him, and make sure the company has done the same kind of work for other clients. Then the board should also check how well that work was done.

“The green movement has had a huge impact on our industry,” says Scaturro. “Everyone is much more conscious of the environment and about the health and safety of the employees and residents. There’s less fumes, paint odors and hazardous materials within paint and cleaning agents now. The technology has changed dramatically. For instance, you can recycle water that we use to clean buildings. Technology has come a long way and cleaning products have come a long way. So it’s a good idea to align yourself with a contractor who utilizes these technologies.”

“Every Tom, Dick and Harry seems to get involved in exterior cleaning,” says Fidgeon. “So it’s important to choose a professional licensed contractor. And you shouldn’t always go for the lowest bid. You get what you pay for.”

“I think the most important thing that people should know about exterior cleaning is that the advances in our industry of cleaning buildings is that sometimes pressure can be the enemy if not used correctly,” says Doherty. “There are professional cleaning products out there that do the work so you don't have to blast every square inch. And it’s always best to have a professional do it.”

Finally, what should one look for in a façade cleaning company? Perhaps Rashkow says it most succinctly; “I recommend that you hire a professional, and get references. Make sure they are properly trained and equipped.” Clearly, no façade job is a ‘small’ job and the success rests on the capability of the team that will execute your building’s façade cleaning plan. Regardless of whether yours is a historic, stone-fronted mid-rise or a glass-and-steel tower, keeping your exterior clean is a matter of both appearance and responsible maintenance.                  

A.J. Sidransky is a novelist and staff writer for The New Jersey Cooperator.