By Richard P. Kadlubowski and Coleman H. Bynum
Why should a building's façade be cleaned? The issue of aesthetics first
comes to mind. After all, a clean building simply looks better than a dirty
building. A clean building presents a more hospitable front - and, therefore,
a more attractive real estate prospect - to the public. Just as we put our best
foot forward with a neat, kempt appearance, a building looks its best when free
of the grime, pollutants, and staining that shadow its most visible - and often,
most vulnerable - attribute, its façade.
Of course, not all building façades warrant the same amount of care
and 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.
Consider function: Structures that house commercial activity, in business,
theatre or shopping districts, often warrant a higher degree of cleanliness
than do buildings that house industrial - or less public - activities.
Furthermore, if and when it is decided a building's façade will be cleaned,
it may be that only a portion - for instance, that which is visible from the
sidewalk - will be cleaned. A skyscraper in Manhattan, for example, may be cleaned
from the ground to the sixth floors only, limiting the cleaning effort to that
portion of the building's façade that is visible to bustling commuters.
Cleaning the ground floors only is a viable alternative when it may be costly
- not to mention foolhardy in a pollutant-ridden, urban locale - to clean a
building's façade completely.
Finally, what it takes to clean a building situated in the country is typically
far less an endeavor than if that same building were located in a metropolitan
area. A rural building may warrant only water soaking to remove mild contaminants
(such as dirt), while an urban building would most likely require a more in-depth
cleaning effort - to remove more hazardous pollutants - to achieve the same
level of cleanliness.
While aesthetics is the obvious - and primary - reason for cleaning a building
façade, the effort to expose the substrate for evaluation and repair
runs a close second. It is nearly impossible to gauge the condition of a masonry
substrate, for example, when the façade is covered in dirt, grime, and/or
a coating. In order to determine those areas that need to be patched, repaired,
or resealed - or, in some cases, to even properly identify the substrate - the
façade should be cleaned of any and all elements that preclude its proper
Still another key motivation behind façade cleaning is the effort to
remove damaging pollutants such as sulfur and nitrogen oxides, and other acid
rain pollutants, from the façade. These pollutants serve to accelerate
Case in point: Moisture is the primary cause of masonry decay. When moisture
is coupled with soluble salts from polluted rainwaters or with atmospheric gases,
the decay is accelerated. When the soluble salt dissolves in water, it travels
deep into the masonry substrate through pores or cracks. Once the moisture evaporates,
the salt recrystallizes, exerting tremendous pressures that break down the masonry
Lastly, façade cleaning opens a building's pores and allows the normal
transpiration of moisture. Moisture trapped within a masonry wall, for example,
will remain there if a waterproofing coating prevents its exit. In this case,
as moisture is the leading cause of masonry decay, comprehensive façade
cleaning to include removal of the waterproofing coating may be the key component
of a professional's effort to restore the building.
Richard P. Kadlubowski, AIA, and Coleman H. Bynum, AIA, senior architects
with Hoffmann Architects, oversee a variety of façade cleaning projects
for the firm. Hoffmann Architects (www.hoffmannarchitects.com)
has offices in North Haven, CT; New York City; and Washington, D.C.