Rusting structural steel can cause major deterioration to the exterior envelope of a masonry building.
Spalled terra cotta as a result of underlying rusting steel.
This spall on a piece of limestone was caused by the rusting anchor behind it.
Sealant failure is a major contributor to masonry and concrete issues.
Improper installation of sealant can result in joints that are exposed to the elements.
When applied at near-freezing or freezing temperatures, mortar will not set properly which will ultimately lead to masonry deterioration.
In common with the human body, defects inherent at inception or that develop from wear and tear, accident or age can present themselves throughout the life of the exterior of a building. Unlike the human body, virtually all defects can be repaired or replaced and the building can be given indefinite life.
Many exterior problems are inherent in architectural or structural design or materials that are deficient or inappropriate to local weather conditions. Other problems develop as weather wears down or infiltrates surfaces or from accidents of nature such as lightning, wind storms or rapid temperature movements. Age inevitably plays its role as materials become brittle, weak or tired from repetitive cyclical change.
As with the human body, early detection, proper response and timely maintenance can prolong a building's life and the quality and value of its existence. The accompanying photographs depict conditions of neglect that are frequent causes of deterioration and need for major repair in Chicago buildings.
Effects of Weather
Chicago's climate is very tough on buildings. Every structure is vulnerable to the wind driven snow, sleet and rain. In addition, the city's extreme temperatures and rapid temperature changes exacerbate exterior problems by causing expansion and contraction of building facing units that create lifting and heaving of building materials.
By the time you notice the effects of weather, it's probable that serious deterioration has already occurred to masonry, supporting steel and wall ties.
Often, the damage starts at the top of the structure through leaking roofs and flashing. In more modern buildings, leaks in and around metal window frames can migrate and cause damage to the wall and to interior spaces. Rusting of supporting elements can affect the integrity of exteriors. This can be seen in concrete spalling at columns, spandrels, floor slabs and balconies, as reinforcing bars rust and expand.
Maintenance and timely repair of weather related problems, combined with regular surveillance, is the only sure way to beat Chicago's notorious climate.