Advanced Air Sealing
This guide is for builders, designers, trainers and those that promote the construction of energy efficient homes. The nature of most residential buildings varies greatly depending on the climate, materials and local custom. This guide hopes to explain basic principles of air sealing and illustrate these principles with details for basic wood frame construction. Its assumed that most walls and ceilings are covered with gypsum board. While the principles of air leakage and construction planning would apply to many building systems, some of the details may not. For example, you could easily adapt the construction details for use with foam core panels. However, relatively few details would apply to log construction or rammed earth.
Dont think of these principles as a rigid system. Instead, its a way of thinking. In some cases, several options are offered. You should choose the one that fits your situation. Or, you could develop your own approaches.
The one overriding principle is good planning. An entire section is devoted to pre-construction analysis and planning. The Air Sealing Checklist in Appendix A helps you plan the job and assign tasks to workers. The Materials List in Appendix B identifies the types of materials appropriate for various locations.
Its not: all or nothing. You can choose which air sealing details to employ. The more you do, the tighter your house. By doing nothing you choose to build a leaky house. At the other end of the spectrum, you can install a continuous air barrier. In between, you could select a set of individual air sealing measures. While there are good reasons to strive for maximum tightness, you may choose to stop short. If so, it makes sense to invest your effort in the tasks with the greatest returns.
Each builder decides how much tightness to strive for. Some have a misguided notion that air sealing should be avoided because uncontrolled leakage allows buildings to breathe. Other builders seal major plumbing and electrical penetrations as well as the rough openings around windows and doors. Think of this as standard air sealing. This guide promotes a higher level of tightness called advanced air sealing. Achieving this level of tightness requires a continuous air barrier. Theres nothing new about the idea of a continuous air barrier. Hopefully, youll find the construction details and the organizational strategies in this guide helpful in making advanced air sealing a part of every building project.