Jonathan Smegal and Dan Morrison

This chart explains how moisture behaves in the air as temperatures rise and fall—rainstorms, flooding, and glaciers in wall cavities are distinct possibilities.

You can't simply go down to the hardware store and buy a box labeled air barrier

Vapor barriers cause a lot more harm than good in many parts of North America. Understanding vapor barriers begins with knowing what it means to be one

Like an out-of-plumb wall, an insulated and unvented roof can work well—or not.

Thin foil can block massive amounts of heat transfer, but it needs a massive temperature difference to be effective. So, insulation sort of makes radiant barriers irrelevant.

Houses cannot expand and contract with changes in pressure like balloons can. Instead, they need paths for air to balance the pressure