Tight Construction

Without a doubt, modern construction practices have resulted in houses that are much tighter than those built a hundred years ago. One of the reasons for this evolving tightness is the use of sheet materials—with drywall and plywood, there are fewer random holes for air to pass through. Plus, windows and doors continue to improve—today, virtually all manufacturers make products that seal very tightly.

In the 1970s, builders began experimenting with houses that were built as tight as possible. These super-insulated houses had phenomenal energy efficiency—in the midst of an energy crisis, they had heating bills of perhaps only $100 for an entire year. Of course, there were some early mistakes, but these houses eventually led to a very good understanding as to how a house can be both healthful and energy efficient.

Today, builders specializing in tight, energy-efficient construction often have reputations for building high-quality, healthy homes. But some people still remember the early mistakes and they condemn tight construction, citing the poor indoor air quality and excess moisture found in a few of the first houses that were built as tight as possible. And medical professionals sometimes link tight construction to indoor pollution, without having an understanding of building science. That’s like having a contractor discuss brain surgery. Some people have gone so far as to suggest that we return to building loose houses. This isn’t very forward thinking.

If we built houses like they used to, we wouldn’t be able to afford the energy bills and, even with the high bills, we’d still be cold in the winter. A large turn-of-the-nineteenth-century midwestern farmhouse could have easily used a train-car load of coal in the winter—and still be drafty and uncomfortable. Instead of moving backwards, we should look at the tight houses that have no moisture problems—and good indoor air quality—and learn from them. Even with houses getting tighter, there is still room for improvement. In other words, with a little effort, many of the houses being built today could be built even tighter. In previous articles, repeated references were made to tight construction. This article will tie together what is known about tight construction, show why it is a good idea, and explain how it is integral to the systematic approach to house design and construction.

Misconceptions

Misconception #1: Tight houses have poor indoor air quality. Some do, but so do some loose houses. The problem isn’t related to tightness as much as it is to the use of unhealthy building materials—and a lack of mechanical ventilation.

Misconception #2: Tight houses have moisture and mold problems. Some do, but excessive moisture and mold are also common in loose houses. Moisture and mold problems are often due to foundation or roof leaks, l...