Moisture Control
Moisture, moisture everywhere. You can’t lock it out or prevent it from forming or keep it from traveling on warm air. To manage this you need a system that allows zero airflow through the wall but allows moisture to move out if it builds up too high. (This is exactly what a tree does, by the way.) The common use of Sprayfoam totes a benefit in decent air sealing, but in reality the air sealing isn't high enough to stop the dangerous flow of warm, moist air. On top of that, since the R-value is increased there isn't enough heat moving through the wall to bake them dry again. Moisture problems and mold are common side effects.
Preventing moisture from collecting is an important aspect of home protection, but drying is the key. Unfortunately, these concerns are often skipped by “experts”. What we should be concerned about is bulk water leaks, air leaks, and high moisture (inherent in warm interior air) - pretty much in that order regardless of region.
The approach we like best uses a system that protects from all three wherever you live. Your home needs total airtightness on the inside and outside, a vapor open exterior with vented cladding, and a smart interior barrier that changes permeability. This technique keeps all interior moisture from getting into the walls in winter but allows any moisture in the wall to dry inside during summer. This isn’t a requirement for all climates, but this approach prepares a home for future unknowns.
This approach is better equipped to handle all the complex variables, like bulk water. A solid envelope without any holes keeps bulk water, like rain, from pouring in. Airtightness helps protect against vapor, think water carried in the air, since vapor through even tiny air leaks can bring in a pallet full of water. A code minimum system doesn’t stand a chance.
Comfortable Building strategies carefully model and balance a comprehensive set of factors including heat emissions from appliances and occupants to keep the building at comfortable and consistent indoor temperatures throughout the heating and cooling seasons. These complex variables need careful planning to keep your walls and entire house protected.