Exterior Wall Maintenance
Know the Basics. Collect Data. Look Long-Term.
In today’s economy building owners have a renewed focus on maintaining building envelope systems rather than replacing them. While proper maintenance is always more economical in the long run, the economic downturn has most certainly inspired special attention to and care for existing assets.
So, what do you do if you’re charged with solving chronic leakage problems for your company? First of all, rest assured while solving leaks and preserving the value of exterior wall systems can be challenging, it is a manageable task. Following a few basic principles of effective building envelope management will help secure a successful approach. Before you get started, consider how the following insights should work into your game plan.
Know the importance and worth of the task.
Approach the task with a high sense of purpose and responsibility. The success of your efforts is important to the corporation, its employees and stockholders. Here’s why.
The exterior skin, insulation, windows and structural support systems of the building are important corporate assets with high replacement values. Their performance is critical to protecting the company’s core business and administrative functions. These systems house and ensure a safe, productive work environment for the company’s employees, vendors, customers and the general public.
Any remediation project and/or asset management program must begin with quantifying the task – whether it is the number, location and severity of leaks within a building – or the quantity, type, age, condition or remaining service life of the various components which make up the wall systems.
Begin by establishing a reliable leak reporting and validation process for observed water infiltration problems. The procedure will vary by organization, building size and building maintenance staff availability, but the leak data should be reported to and verified by a specific individual who understands the importance of accurate leak information. At a minimum, the leak report should include: date, time, floor level, elevation (N/S/E/W), specific location (i.e. office number), window/wall location (i.e. head of 3rd window) and severity (condensation, drips, trickle, continuous flow, serious flood).
Accurate leak data is a critical first step in developing an effective, efficient survey and remediation project. Too often the condition assessment efforts have begun with “it leaks everywhere,” when in fact the building only leaks at the heads of the windows on the 7th and 8th floors on the north elevation and at the spandrel panels and floor lines on the 14th, 15th, and 16th floors on the south and east elevations. The cost, schedule and scope of the condition assessment, and the design and remediation phases can be greatly reduced and simplified with detailed leak history data. This data provides a valuable initial understanding of the scope of the problems: Are the leaks isolated? Systemic? Wind dependent? Temperature dependent? Vertically oriented? Growing in severity?
Invest in a professional inspection when necessary.
The scope and focus of an exterior wall survey should be based upon the nature of the leakage problems and the type of construction involved. Due to building heights, the exterior wall investigation process can sometimes be both expensive and time consuming. While a visual review using binoculars from ground level and intermediate roof or balcony levels is a good starting point, it is considered cursory. Since visual inspection is not definitive, except for the most serious distress conditions, lift equipment or swing stages are normally utilized for access to perform inspection, material sampling and water testing activities. The cost of these materials can represent 20-30 percent of the total survey cost.
Although full exterior inspections are sometimes required for forensic or litigation cases, one can be successful with selective (but detailed) inspections on one to two swing stage drops (typically 30’ vertical sections of the building exterior) on each elevation. An additional inspection drop may be required to investigate special features or observed distress conditions. Selective inspections generally are 20-30 percent of the cost of full surveys.
Inspection locations should be selected to access, inspect and test all components of the exterior wall systems at each floor level. In addition to detailed visual inspection and quantification of each wall system component and their relative condition, placement, attachment, expansion provisions and joinery, some of the following testing procedures may also be utilized:
Sample extraction, dimensional and material testing of sealants and gasket materials;
Mil thickness testing of coatings or paint finish;
Rylem tube testing of absorption rates on masonry, concrete, stone or other surfaces;
Compression testing of gasket/glass interface in the window system;
AAMA 501.3 field static water infiltration testing;
ASTM 783 air infiltration test;
ASTM E546-88 test method for frost point of sealed insulating glass.
Proper attachment of exterior wall components is critical to performance and safety considerations. The survey should include inspection of structural framing and anchorage conditions at random locations, especially if movement, damage or distress of any wall components is present. This review may involve removal of interior ceilings or wall finishes for access and/or boroscope cameras to investigate demolition and reconstruction costs. In some systems, sectional removal for investigation of construction conditions may be necessary. It is easy to overspend for testing and inspection procedures. Although valuable tools, the location, scope and cost of any testing procedures, system demolition and inspection activities should be validated as relevant to resolving observed problems.
Despite the variety and complexity of all systems, the “source causes” can be identified and corrected with the following in mind: access cost, risk, safety and disruption of high rise remediation projects. All sealants, gaskets, coatings and insulated glass units have limited and predictable service lives. Their remaining service life and cost, risk or disruption of future projects should be considered in finalizing the scope of the project. Invest in selective, limited repairs for specific problems. Consider full scale, comprehensive renovation when the leak problem conditions are widespread and/or wall system components aging and remaining service life is therefore limited.
A good condition assessment should include a 10-year estimate of future maintenance and remediation needs and associated costs. And don’t be surprised at the real cost of ownership. The greatest value your research and time can offer corporate and financial management is a true estimate of the building’s needs. Accurate knowledge of their asset management costs is what they need most.
Bill brings over 20 years of roofing industry experience to the benefit of Conley Group’s clients. His proactive and tireless efforts consistently provide clients with the greatest opportunity to achieve a successful result and positive return on their expenditures related to roofs, walls, plazas and related waterproofing. His work on corporate programs and industry panels keeps Conley Group on the leading edge of the industry through the integration of financial management and technical expertise. Bill can be reached at 800-809-2821 or email@example.com.