way to keep crawling up the learning curve. Crawling Up the Learning Curve A substantial percentage of space in New England Builder is devoted to the "fuzzy" areas of building design and construction: attic ventilation; how tight houses should be; where vapor barriers should go; optimum-value engineering; vapor-permeable air barriers; foundation drainage problems, and more. These are exciting topics for builders, issues that can occupy hours of conversation. These topics are most prevalent in the area of energy-efficient construction. This is understandable when you consider that the techniques and materials have been in use for a decade at most, and often for much less time. The long-term performance of new materials and techniques cannot adequately be demonstrated through short-term laboratory tests. Even in real buildings, problems may
