How Do Suction Cups Work?
Have you ever thought about how suction cups work? It's got to be suction, right? Or is it? As it turns out, all we need is some basic physics to explain suction cups. And of course there's a connection between…
air barrier
Do Airtight Houses Need Makeup Air?
When you turn on an exhaust fan, it blows air from inside the house to the outdoors. That air leaving the house will be matched by an equal amount of air coming in from outside. The more airtight the house…
How to Avoid the Flaw in Structural Insulated Panel Construction
Before 2001, the biggest construction project I had ever taken on was a bookcase. My most complicated project was probably the mahogany lamp table I built in tenth grade shop class. (I still have it!) Then I decided to build…
Is Wind Washing Reducing Your Insulation R-Value?
You'd think that after more than 12 years and a thousand-plus articles, I'd have mentioned all the major building science terms by now. Yet, here we are. I just did a search of all the articles in this blog and…
A Continuous Air Barrier Between Garage and House
An attached garage is the source of a lot of indoor air pollutants for a great many homes. That's because we store gasoline, pesticides, paints, and other toxic materials there, and we exhaust the fumes of automobiles there as well. …
The Ol’ Beer Can Pressure Crunch
Air has weight. Air can move things, like giant wind turbine blades. Air can also crush things. I first got to see the power of air in my introductory physics class in college. The professor, Dr. Jeffrey Trahan, showed the…
Air Sealing an Attic Access the Right Way
Attic access points can be a mind-blowing thermal liability. If you don't believe me, open the pulldown stairs or scuttle hole and go into an attic on a cold day. Then turn around and look down through the hole. You'll…
Building Enclosures Have Improved More Than Ducts
Yesterday I visited a home being built by a national production home building company. As you can tell from the title of this article, I have good news and bad news. The good news is that building enclosures have improved,…
Where Should the Air Barrier Be Located?
Where to put the air barrier may seem obvious, but this question has many dimensions…literally. Let's look at the question of air barrier location from three perspectives. First, building assemblies are three-dimensional. The air barrier can go on the inside,…
An Insulated Sheathing for Building Enclosure Control Freaks
Building enclosure control freaks know that a good exterior sheathing can make a huge difference in performance. Controlling the flows of moisture, air, and heat requires good control layers. A lot of materials and methods will get you there, but…