A building’s exterior façade can experience water infiltration anytime during a its lifetime. The façade is composed of a variety of components including windows / door penetrations; wall cladding; and features such as balconies and other architectural elements. Water infiltration can occur while the building is undergoing transition from developer to a new condominium organization or a 30+ year old building with no history of leaking.
Addressing a leaking building cannot be long delayed due to the risk of mold/ mildew developing; structural damage; aesthetic degradation; legal issues; and potential personal property loss. Depending on the nature of the water infiltration the board should exercise due diligence in addressing the source of moisture and the necessary repair. Simply turning over the problem to the first contractor with a caulk gun has led to serious regrets.
The villain in most façade failure mysteries is typically water. It causes corrosion; erosion; internal leaking; paint peeling; rot; settlement; and a host of other building envelope woes. If your building has concrete elements suffering from spalling or cracking it might be due to the reinforcing steel in the concrete becoming heavily corroded due to water penetrating the surface. Ordinary rust scale expands with incredible force per square inch when confined, think bulldozer power.
Many absorptive façade materials (concrete, sandstone, mortar, fired-clay masonry) can be seriously damaged by cyclical freezing and thawing of water entering the material through natural porosity or surface hairline cracks. These pockets of moisture can be trapped in façade walls whose freezing can expand causing further cracking, spalling, or displacing adjacent masonry by a phenomenon called ice lensing.
This spalling can create dramatic loss of structural integrity to parapet walls; retaining walls; and cantilevering decks not to mention the safety hazards from falling façade components. Complicating the diagnosis problems and the repair solutions is that spalling concrete is caused by forces other than water. Similar concrete failures can manifest themselves by compression, tension, or vibration overloading.
Equally important in a façade investigation is understanding what materials make up the façade, as looks can be deceiving. Most of the old brick buildings in major cities use the exterior brick to support the interior floor framing and are thus called ‘bearing wall masonry’. These heavy walls were designed to prevent moisture from entering the building’s interior spaces by the brick absorbing water in its multi-layers of brick and drying out when the weather improved. Over a hundred years ago steel framing was introduced allowing the building designer to hang the exterior façade skin on the perimeter of the frame to produce more lightweight and cost effective buildings. Today’s brick building uses brick as a veneer in which the brick is only the first line of defense against water infiltration. The brick shields the true water barrier sheathing behind a cavity space. This cavity acts as a drainage channel with weep holes at the bottom of the brickwork.
Similarly, many older buildings are covered with a stucco façade surface which is a cement parge coating over a steel lattice similar to plaster placed onto wood lathe strips. Modern buildings use an EIFS (Exterior Insulation Finishing System) seen on many condominium and retail building exteriors. An EIFS façade depends on interior drainage surfaces and is totally different in repair methods than stucco.
To address these questions there are a variety of invasive and non-invasive techniques to investigate the problem. If the concern is corroding imbedded steel, there are firms providing chloride ion content testing of concrete or mortar to gather quantitative evidence of corrosion potential. Simple stain gages can be placed over cracks to detect active movement. Infrared thermography can discover unseen façade connection failures; delaminations; or thermal ‘short circuits’ due to wet insulation. There are a variety of water moisture content meters available at building supply stores and woodworker hobby shops that can accurately detect and measure moisture in a variety of materials including wood, drywall, and concrete.
Often the insurance company will recommend a third party forensic ‘Water Penetration Testing’ program including a set of standardized field tests the American society for Testing and Materials (ASTM E 1105) has developed. The investigative steps can include 1) establishing an interior test chamber sealed to prevent air leakage; 2) setting up a calibrated water spray rack to simulate rainfall on the façade element; 3) use a blower system to create air pressure differential designed for expected weather conditions; 4) spray testing with established test / rest duration periods: 5) documented inspection test results monitored by certified forensic technicians; 6) results analyzed and solutions presented for remediation.
In addition to judging the cause of the façade problem, it is important to determine its seriousness and whether immediate repair steps are necessary or whether it is not an ‘active’ problem that can be set aside to allow other more pressing issues requiring capital outlays from the reserve fund. As these decisions can be difficult, a wise board will call upon a licensed architect or professional engineers to assist in this effort.
Written by Jack Carr, P.E., R.S., LEED-AP, Senior Consultant Criterium Engineers
Published in Condo Media