Is Yours a Sound Structure?

Deterioration of facades is a normal consequence of aging or poor construction, so it is a problem all building owners and facility executives should keep an eye out for. Problems can begin within one year of construction or less, so close attention must be paid to new buildings during the guarantee period. In older buildings, a yearly or bi-yearly inspection by a qualified professional is good protection against falling masonry or shifting appurtenances.

No type of building is immune to deterioration in one form or another. Some problems are the result of age, but newer buildings can age more quickly than older ones because the new materials used in construction are not as resistant to weathering as historic materials are.

The usual culprit behind facade deterioration is water — either as a liquid or ice — combined with masonry movement. Masonry will shift seasonally along a facade — 1/2 inch for every 100 feet — and crack if expansion joints are not present every 30 feet to accommodate the movement. The cracks will grow over time and require intervention.

Deterioration Causes
Problems can occur in different areas of a facade. Due to differences in construction, various building types have specific design characteristics that make deterioration more likely to occur in one area than another. Some of the defects that appear may be due to a lack of knowledge on the part of the original architects or engineers about how facades work.

There is always a learning period associated with the introduction of new techniques and materials. Post-World War II buildings, for example, tend to have corner cracking and parapet movement because their walls are thinner than those of earlier buildings. Thinner materials are more vulnerable to deterioration and depend more on caulking than on redundant details like overlapped flashings. Tall buildings of the World War I era are subject to the corrosion of their structural frames that causes brick bulging in localized areas because flashing was not always used at spandrels (floor line), beams or columns to protect against water infiltration.

In addition, before 1950, no provision was made for water, which is always present in building walls, to weep to the outside. As a result, low-rise buildings constructed during the early 20th century suffer from the rusting of decorative elements and appurtenances, although they have no metal frames.

Traditional stucco buildings with stucco applied directly to block have a surprising durability that is due to the integral color in the stucco. The urge to paint such buildings should be resisted since the original color can be quite long-lived, whereas paint would require maintenance every two to five years. Instead, an effort should be made to clean the stucco to improve its appearance.

One of the most common problems that occurs on a masonry building facade involves non-structural metal pieces or elements such as fire escapes, flagpoles or lights. These elements corrode and come loose, and the masonry cracks above windows and at corners. Items such as lintels — the horizontal steel elements that support the brick above windows — corrode, causing the masonry to crack. Parapet corners tend to "walk off" the building because they lack the rods to anchor them to the roof slab, causing step cracks to appear at parapet corners. Limestone, granite and marble on facades can move or crack as well, a common symptom of inadequate initial design or the deterioration of anchors. White staining of a facade (dusty salts called efflorescence or thick, grayish crusts called carbonates) is a sign of water movement through the masonry from above or behind. It indicates that the roof, cornice or gutter flashings may have gaps or that parapet coping joints have aged and shrunk, allowing water to enter.

Water Penetration
The consequences of these problems include falling masonry, structural deterioration and water penetration. Parts or entire elements may fall off a building facade and injure someone. The problems can also result in further deterioration by allowing water to seep into the building, causing interior finish and equipment damage.

Although windows are often neglected and their poor performance (wind infiltration) may be a source of occupant dissatisfaction, they contribute little to building deterioration. They may be systematically maintained by routine painting, repair of balances, and tightening or adding weather stripping every 20 years or so. If they are properly maintained, the original windows in older buildings will usually outlast replacement windows by a substantial amount.

If problems are prevented beforehand, they will not require remediation. A building should be examined often, particularly the roof and walls, to establish how it looks when it’s safe and in good condition. Familiarity with the building’s appearance when it is free of problems will serve as a guide if cracks begin to appear where they haven’t been seen before, such as where a flagpole moves out from its base and exposes unpainted material.

Inspection and Repairs
A layperson can detect some symptoms, as will a conscientious superintendent. However, a periodic inspection by an expert is still recommended. To prevent problems from occurring, a qualified architect or engineer should inspect the building every year or two and write a report that includes photographs or sketches of any deficiencies found.

Large buildings should be inspected yearly. The documentation will show the location and rate of deterioration from year to year and indicate how quickly a particular problem should be taken care of.

If symptoms are not detected or dealt with before they have turned into a problem, remediation should be handled by a reputable contractor.

In repairing the facade, loose appurtenances should be reattached, and cracked brick should be replaced or small areas rebuilt. Note that repointing is seldom a remedy, but is most often suggested by contractors who are not sufficiently knowledgeable.

Each problem should be addressed by type. Water penetration at horizontal copings, sills or cornices of masonry facades requires the sealing of all penetrations at joints between individual stones or at the sides; in some cases, the epoxy consolidation of wood is also required. Non-bearing masonry curtain walls in all buildings more than six stories built since 1900 undergo frame corrosion and parapet movement. Repairing this problem requires the removal of the masonry in front of the corroding steel, cleaning the frame and reinstalling the masonry.

To address parapet movement, the shifted brick must be demolished and rebuilt. Corner cracking calls for strapping in place or demolition and rebuilding of masonry. Solid masonry on steel frames on buildings constructed up to 1950 also undergoes frame corrosion and floor-line bulging. This also calls for localized demolition and rebuilding.

The facades of other types of buildings are afflicted with different types of problems. Glass and metal curtain walls in commercial structures, for example, undergo sub-frame corrosion and spandrel glass cracking as a result of hardening of linseed oil caulk. Curtain wall deterioration will probably require disassembly and refurbishment.

Other difficulties have occurred with exterior insulation and finish systems (EIFS). In this method of construction, the insulation of the building is mounted on the exterior of the wall, instead of in the traditional space between the studs, and a thin coat of mesh and cement plaster is applied over it. EIFS achieved great popularity during the energy crises of the 1970s. However, the system’s anchors sometimes pull out and require reattachment. The systems also can suffer from excessive admission and retention of moisture, which permits the growth of molds. The system has been banned in some Southern states, and its application is restricted in Chicago.

Please Don’t Prove the Point

Problems should be addressed as soon as it is financially feasible. If they are not, they will pose a danger to pedestrians, allow more water penetration and cause a disturbance to the building’s occupants. In addition, the rate of deterioration will accelerate so that substantial damage can occur to the interior, affecting flooring, furnishings and equipment. The result will be higher costs in the long run.

Roof deterioration should be addressed as soon as possible since the roof is the structure’s main protection. This includes sealing open coping joints. Masonry cracking should be taken care of immediately to protect the public if any hazardous conditions are found. Corrosion or movement of appurtenances can be put off if the rate of deterioration is found to be low and the elements are determined not to be close to failure.