Microbial growth can occur from water infiltration that occurs during the construction process, or while a building is being occupied and maintained. Once construction is completed, moisture may be an issue due to events that occur (such as leaks, spills, and overflows), maintenance work on the facility (or lack of), or due to moisture incursions that occur due to some defect in the design and/or construction of the building. The focus of this presentation will be the design and construction defects and examples of the various issues will be offered.

Steps taken during the design, contracting, material purchasing and construction phases to minimize or eliminate potential or likely infiltration or retention of moisture can significantly decrease potential microbial growth from construction defects. For example, siting issues for buildings include the immediate and more distant water drainage, level of the building relative to the grade, and an understanding of how prevailing winds or fog can require additional design considerations for moisture control. Materials need to be selected that are compatible with each other, regarding moisture infiltration/permeation. Potential incompatible material conflicts may occur in adhesives, caulks, envelope components, insulation and vapor barriers.

Ventilation system design and construction not only is a key area where moisture may be retained or infiltrate, but the ventilation system can distribute any microbial growth throughout the system. Key areas for infiltration concerns include the placement and design of the outdoor air intake, the drip pan, and ductwork.

Even if all design and specification concerns have been addressed to minimize water infiltration, the construction/installation methods used and how materials yet to be installed are stored can negatively impact the potential for microbial growth.

• fungi: moisture damaged house -- indoor microbial concentrations
• fungi: molds in buildings

1. Air- and dustborne mycoflora in houses free of water damage and fungal growth
2. Building-associated pulmonary disease from exposure to Stachybotrys chartarum and Aspergillus versicolor
3. El Ni?o water leaks identify rooms with concealed mould growth and degraded indoor air quality
4. Hidden mold sometimes enters the indoor air
5. Microbial VOCs as indicators for mold growth in buildings
6. Mitigation of visible fungal contamination in buildings: experience from 1993 - 1998
7. Practical aspects of sampling for organic dusts and microorganisms
8. Use of fungal detectors to monitor drying of water damaged buildings
9. Water leakage from exterior walls as an indicator of degraded air quality