Façade Cleaning Safety, Solvents, & Curb Appeal

Shanghai, China - March 26: Exterior cleaning and building cleaning with high pressure water jet on March 26, 2016 in Shanghai, China. Shanghai is the largest Chinese city by population.

As the old saying goes, you only get one chance to make a first impression—which is why the façade of your building should always look clean and in top shape, for both aesthetic and commercial reasons. Important as appearances are, however, a neglected façade can ultimately cost a building or association more than just poor presentation. Façades serve two very specific purposes: they’re the face your building puts out there to the world, and they serve as a literal ‘envelope,’ sealing off the interior structure from the elements.

Keeping it Clean

The most critical factor in façade maintenance may well be regular cleaning and upkeep. Whether your exterior is brick, stone, wood, or vinyl, establishing a program to keep your façade in top form is critical to averting much larger long-term repair projects. 

“There are three main methods used in the building envelope industry for cleaning façades,” says Marcello Tronci, an associate with CTL, an architectural and engineering firm with offices in New York and Chicago, “water treatments, chemical treatments, and abrasive treatments. Their application varies in many aspects depending on what type of material the building envelope is made of.” 

Tronci explains that “the most common water-based cleaning method by far is pressure washing, in which a low- to medium-pressure spray (100 to 400 psi) is applied to the surface of the building. Chemical cleaners,” he continues, “may be sprayed or brushed on a wet surface and then rinsed off with water after completion. Before water is applied, these chemical components need to sit on the surface for a certain period of time, depending on their composition and the material or dirt being removed. In general, we don’t recommend abrasive treatments like grinding, sanding, and blasting. The risk associated with removal of the base material particles along with dirt and paint is substantial, and therefore considered potentially damaging to the façade.”

Reggie Thomas, director of community management for Evergreen Management Group located in Manchester, New Hampshire, notes that “it’s always best to use cleaning products and methods that are surface-specific for different buildings. For softer stone types, you want to use a low-pressure, green-friendly product that will lift the dirt and staining out of the surface, then pressure washers as a rinsing tool. Brick and stone buildings are very porous, so the right product helps open up those pores. When we have a question, we consult with our vendors and manufacturing reps regarding the best method to use for specific surface types. Vendors provide test samples prior to applying their product, to ensure there are no bad outcomes. There’s no one-size-fits-all when cleaning buildings; brick, granite, and concrete can handle more pressure, but product knowledge is always key to maximizing results.”

Dan LeBlanc, a regional manager with FirstService Residential in Quincy, Massachusetts, points out that when chemical cleaning is called for, using a qualified expert is critically important. “It’s tough,” he says. “You can’t just send a maintenance guy to take off graffiti and mildew. You’re using chemicals—and if you don’t use the right ones, you can discolor the brick or stone. Normally, we handle this on a case-by-case basis. If the damage is from graffiti, we bring in an expert to remove it properly. In historical preservation areas like Back Bay in Boston, we have to be particularly careful due to the requirements under historical preservation provisions.”

The Source of the Problem

The type of grime and dirt that accumulates on a façade varies depending on regional geography. In coastal areas, explains Tronci, exposure to air with chloride concentration due to the nearby ocean can cause significant damage to any façade over time. The type of damage caused by these chlorides may be initially aesthetic—efflorescence, corrosion, and crumbling of the material—which in time leads to deterioration of the façade structure and supporting elements, if maintenance and cleaning isn’t conducted on a regular basis. In the Midwest, freeze-and-thaw cycles can be especially damaging to façades, leading to frost heaving, cracking, and other issues. In tropical regions like Florida, strong sun can cause fading and the eventual breakdown of certain materials. In addition to these regional issues, universal pollutants like car exhaust and general city grime cause discoloration, staining, and other wear and tear on a façade over time.

In urban environments, explains Thomas, “Buildings get hit hard with construction debris, black algae, and general air pollutants. Suburban buildings see green algae from trees—especially on the shady sides of buildings, where it will typically advance more quickly. Ocean salt won’t typically reveal itself as much on the façade as it does on glass, but it’s still something to consider. There are some exterior finish products—inferior types of cement board, for example—that are more susceptible to salt exposure and can lead to peeling paint or advanced deterioration of that underlying material.”

In suburban settings, LeBlanc points out that planting shrubbery too close to a building will block out sunlight, making it the perfect environment for mold and mildew to flourish. The same problem can crop up with tree branches. “You need space between the buildings and landscaped areas,” he says. “Another issue is downspouts from the gutters. If they’re loose and water doesn’t drain properly, you get spotting on brick. Brick is like a sponge; the water leakage will affect the grout and mortar as well.”

What to Use & When to Use It

The best route to maintaining your façade is regularly scheduled care and cleaning. Obviously, you can’t schedule this work during the depths of winter, so some advance planning is in order. Here’s what the experts suggest:

Tronci says, “To address these issues, professional façade cleaners typically use a variety of products and methods to keep a façade looking its best. For removing dirt, dust, and grime, professional cleaners may use a low-pressure power washer. For tougher stains and discoloration, cleaners will use specialized cleaning agents and solvents. These solvents come in a variety of forms, including foams, gels, and liquids, and are designed to be safe for the materials of the façade. For more stubborn stains, professional cleaners may use abrasive techniques like sandblasting, media blasting, and pressure washing. Depending on the severity of the damage, professional cleaners may also use specialized techniques like graffiti removal and stucco cleaning.”

Tronci notes that another relatively new method is laser cleaning. “Laser cleaning is a non-contact method of cleaning building façades,” he says. “It uses a high-powered laser to remove dirt, grime, and other materials from the surface. The laser is directed onto the surface and its beam breaks the bonds between the dirt and the surface, allowing the dirt to be removed easily. The laser can be used to clean stone, brick, wood, and metal. This can be a more expensive treatment compared to the others, but given the fact that it is a very low labor-intensive treatment, it can be more cost-effective, especially for decorative stones typical of historical and landmark buildings.

“Typically,” Tronci continues, “the best time of year for a full façade cleaning is in the end of spring or beginning of fall, when the weather is mild and not too hot or cold. The process can take anywhere from a few hours to a few days, depending on the size of the building and the severity of the staining. Most of the time, façade cleaning can be done without disruption for the residents of the building. The cost of a cleaning operation can vary from $2 to $30 per square-foot, depending again on the size of the building, the treatment used, the severity of the staining, and the complexity of the job.” 

Thomas says to keep in mind that “every building is different, even if it’s constructed of the same material” as the others in a community, “so again, leaning on vendor partnerships is important to get this right. Conduct a full review with your cleaning vendor partner to determine a suitable method. Providing samples and taking the full scope of the project into consideration helps with the final decision regarding which method of cleaning is the most appropriate and effective.”

A façade that is clean and well maintained not only contributes to curb appeal, which can help increase resale values, but also is more likely to last longer and require less maintenance in the future, which can save money in the long run. 

A.J. Sidransky is a staff writer/reporter for New England Condominium, and a published novelist. He may be reached at alan@yrinc.com. 

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