8 Building Science Mistakes to Avoid – GWC Mag

There’s a very simple reason why all builders should understand building science—or, in other words, know how buildings work: because buildings, or at least parts of buildings, regularly fail. If you’ve worked as a remodeler, or even if you tackle projects in your own home, you know this story well. You start stripping roof shingles first thing in the morning intending to install flashing and underlayment after lunch. But instead of taking a lunch break, you spend an hour running to the lumberyard for a few sheets of plywood to repair the rotted sheathing below the improperly flashed plumbing vent. Heck, even if you’ve never worked on a home, if you’ve lived in one, you may know the experience of a damp basement, a hood fan that never quite seems to clear the kitchen air, or finish that’s peeling clean off the siding way too soon. Every one of these examples relates to building science mistakes that could have been avoided.

For this reason, I reached out to some regular Fine Homebuilding contributors from around the country and asked them not only what building science mistakes they’ve made or often see, but how things could have been done better. Their replies could easily have been turned into a manuscript for a book, but there were a bunch of common themes, and that’s what you’ll find here—along with a few concerns of my own.

1. Not controlling condensation with exterior insulation

Continuous exterior insulation on walls has several benefits. It’s often a good way to add R-value to existing walls when re-siding an old house. More than just adding insulation, it specifically minimizes thermal bridging, which is why it is also a smart way to insulate the walls of a new house…