These are examples of the possible effects from many material changes that include more synthetics and manufactured products with differing drying characteristics; tighter tolerances leaving less room for drying; tighter production schedules leaving less time for drying and acclimatization; more complex buildings that affect air, heat, and moisture flow in complex ways; and more insulation and better air tightness that reduce drying potential both short and long term.
Managing Micro Moisture
Micro-moisture issues can be addressed the same way as the leading, most reliable strategies for moisture at the macro levels: time and space. Following are things that we know (and have always known) work, but now for other micro reasons:
¦ Keep building materials dry throughout the supply chain and throughout the build process. James Hardie, for example, requires its distribution chain to ensure all pre-finished cement-board siding is stored indoors.
¦ Let buildings and materials dry, even at a daily level. For example, allow exterior siding installed on a cool, wet morning to sit a few hours in the sun before applying final sealants.
¦ Provide outlets for pressure and moisture on the exterior. Builders know that vented rainscreens are an excellent choice in the long term, but they are also helpful in the first few hours of production.
¦ Check for compatibility. With so many material choices available to builders, it is important to confirm with each supplier that their products are compatible with materials from other suppliers.
¦ Adjust methods and processes to match daily weather conditions. For example, provide dry on-site materials storage during wet seasons or tighten up delivery schedules so as to avoid wetting of materials.
There now is enough industry research and access to educational opportunities to help you track the latest moisture-management techniques. Two great resources include the NAHB Research Center (www.nahbrc.com) and the Energy & Environmental Building Alliance (www.eeba.org), which will host its annual technical conference in Portland this October.
Given the ever-increasing complexity of buildings and building materials, it’s comforting to find manufacturers working together to integrate products into a whole-system approach. Builders willing to form strategic partnerships with manufacturers and suppliers, and put aside lowest-first-cost mentality, also can find opportunities to help further product research defining practical and cost-effective building science solutions, which will help them manage their quality.