http://www.realtor.org/RMODaily.nsf/All/CD756BEEE The article barely broaches the topic but it does admit that the "tight construction" myth is just that...a myth. Many moldy new homes are not tight at all, and leak, and that is often why they are moldy. Another cause of mold is condensation behind the siding that rots the OSB sheathing because a house wrap was not installed correctly, or at all. Other waterproofing materials that are often left out as shortcuts that put more money in a bad builder's pocket are roofing felt and window flashing. In most areas these omissions are code violations, which also voids the material warranty and the 10 yr structural warranty policy because the warranty policies usually do not cover code violations. I personally have 2-10 HBW and it specifically excludes coverage for defects or damages that result from code violations. Most of them are about the same.