Duncan,
Have you ever considered that the very reason that you can make so much money in Real Estate is one of the leading causes of leaky buildings

In NZ we have plenty of land relative to the size of the population, yet our elected (and unelected) officials squeeze more and more people closer and closer together in urban areas, downsizing minimum building site sizes regularly.

The positive results for property investors - scarcity of development land, high density infill housing, low home affordabilty -ie high and rising prices.

Architects have responded to the challenge of building large homes on small sites while still complying with recession plane regulations (for best profit margins, and the sheer challenge in some cases no doubt)have designed houses with box windows, no eaves and internal gutters and decks - the prime cause of leaky buildings.