Just like in medicine, early detection provides the best chance of limiting losses when it comes to façade performance. Here are the top five tell-tale signs of problems:
Buildings talk to us if we learn how to listen. Cracks are materials’ way of saying “I want to move, but can’t” or “I can’t take this stress anymore.” Some materials, like concrete and stucco, develop fine shrinkage cracks (similar to cracks in dried-out mud); these are normal and nothing to worry about. Signs that may be indicative of more serious problems include wide cracks, vertical cracks running up concrete or masonry columns, and cracks near a building’s corners. After an earthquake, x-shaped cracks often appear in piers between windows, as well as where towers and lower portions of buildings come together and pound against each other. All cracking should be evaluated by a trained engineer who can recognize which cracks are normal and which are signs of serious problems beneath.
All building materials move in response to temperature changes. Many also move in response to moisture changes. However, obvious displacement of one material vs. another often indicates a lack of necessary control joints to accommodate such expected movements. Unattended, continued displacement results in serious damage to the materials and, perhaps, danger to the public. Look up at your building and assess cracks and pieces of the cladding that are out of plane with the rest of the façade.
If we didn’t put holes in walls, there wouldn’t be many leakage problems. But, alas, we like windows. Windows can leak through the window parts themselves (less likely) or around the windows (more likely). Through-the-window leaks generally result from frame corners that were once sealed in the factory but have become unsealed, or from external gaskets that have lost their ability to seal between frames and glass. Window-perimeter leaks generally result from inadequate design and/or construction of the joint between the window and the façade. It is critical to determine the cause of the leak before undertaking a repair, or your efforts may be completely wasted.
Building materials don’t last forever and need periodic maintenance. Look for hardened or cracked sealant joints, shrinkage of window gaskets, cracks and erosion in mortar joints, and blistered or peeling paint. Pay particular attention to window sills, ledges, and tops of parapets - all of which must act as small roofs to shed water.
When you leave your bicycle out in the rain, you can see it begin to rust almost immediately. Building façades are more insidious - the steel in buildings is usually hidden beneath the surface as reinforcement in concrete buildings, and anchors and ties in brick, stone, and terra cotta-clad buildings. When this steel rusts, the rust product expands with enough force to crack and cause the surrounding concrete or masonry to fall off. Early signs to look for are orange rust stains and cracks in locations where steel is likely to be found (over windows and at steel columns in masonry-clad buildings, and in a regular grid in concrete buildings). The sooner you act to cut off the water supply and repair the corrosion, the less damage you’ll have later.
Carolyn Searls is a senior principal at Waltham, MA-based Simpson Gumpertz & Heger Inc., and head of its Building Technology practice on the West Coast. She specializes in repairing building façades and structures, and can be contacted at (firstname.lastname@example.org).