Building durability - Know what you know or let's use the knowledge we already have, before we improve upon it

We encourage the use of our professional experience to get the most of old and new materials and construction methods to obtain durability in buildings, by better and more consistent use of knowledge we already have. Recent experience shows that major buildings fail in their function after as little as 30 years for disparate reasons. We examine some of these reasons by looking at practice of design, contracting and construction as follows: things designers know or don't know; when contractors build, do we know enough?; the manufacturer's contribution B or lack thereof; and, how we organize labor and material.