Although it's not often directly addressed by green building standards, moisture control in building design, construction and maintenance has a significant impact on building air quality and longevity.
Moisture-related issues are one of the greatest threats and challenges to the durability and health of buildings – two of the core elements of what makes a building green.
Beyond the obvious impact of moisture damage (for instance, in the event of a sudden event such as a burst pipe), unchecked moisture problems like a slow leak at a window or through a foundation can be responsible for significant heath problems.
They also can cause property destruction if moisture conditions lead to mold and mildew, and significant long-term structural degradation, such as dry rot, corrosion and rust.
Unfortunately many moisture intrusion problems are undiscovered until significant damage or mold growth has already occurred, and by the time these issues become obvious, the problems require significant remediation expenses.
New construction considerations
In new construction, the design team and contractors should consider advancements made in the building envelope and building science industries to take advantage of new best practices, techniques and technologies.
Quality construction and proper installation is critical to avoiding moisture problems – even if you have the best detail, if it is not installed correctly, it can still fail. Testing installed systems is also recommended.
Many of the advancements in the industry relate to improvements of old technology, more climate-specific responsive techniques and development of new systems. Some experts in the building science community are even challenging some of the ways things have been traditionally constructed.
Flashing systems around windows, doors and other exterior penetrations have always been important, but more emphasis than ever is now placed on these critical detail areas in building envelope construction.
New advances in flashing materials and different installation techniques are providing more change to the industry.
Similar to some of the high-tech outdoor clothing now available for extreme sports enthusiasts and weekend warriors, rainscreen cladding systems are quickly becoming common here in the wet Northwest.
These systems not only shed rain, but combat wind-driven moisture from entering the building envelope. A vented airspace between the screen siding material and a drainage plane provides a capillary break, allows unwanted moisture to drain out and permits air flow to dry behind siding if any moisture manages to get past the first protective cladding outerwear.
Problems in existing buildings
As budgets become tighter and building owners look to cut costs, it may be tempting to avoid deferring necessary maintenance related to the building envelope and other moisture-resistance related systems.
But any short-term savings in deferred maintenance could pale in comparison to the costly repairs and impacts of future moisture-related problems.
If there is a leak or an issue discovered, it is important to not just repair the symptom. The source of the problem needs to be investigated and corrected – this is not always easy, especially if the condition is in a concealed space.
Unrepaired primary conditions will undoubtedly return. Proactive maintenance and immediate repairs of infiltration or leaks will undoubtedly be far more economical than the alternative.
Timothy Buckley is principal of Vancouver-based Greenstone Architecture PLLC. He can be reached at www.greenstonearchitecture.com, 360-695-5454 or tbuckley@greenstonearchitecture.com.
