“Perfect Wall” for Des Moines Iowa

This is a homeowner forum post, not news, so there's no policy or program update to report. A person building a new house near Des Moines, Iowa, is asking for advice on wall construction for a roughly 1,800-square-foot home attached to a shop and a walkout basement.

The poster wants what builders sometimes call a "perfect wall" design: insulation placed both outside the wall sheathing and inside the stud cavities, rather than relying on cavity insulation alone. Their plan is vinyl siding over a vented gap (a "rain screen"), then a layer of exterior foam board insulation, a weather-resistant barrier (a coating or wrap that blocks water but lets the wall dry), wood sheathing, and cellulose insulation blown into the wall cavity. The goal is a well-sealed, well-insulated house that resists moisture problems like rot and mold over the long run, paired with a heat- and energy-recovery ventilator (a small system that brings in fresh air while keeping conditioned indoor air from being wasted).

There's no dollar figure, rebate, deadline, or program mentioned here — just one homeowner comparing insulation and moisture-control approaches before building. If you're planning new construction or a major renovation in a cold climate, this kind of layered wall assembly, with insulation on both sides of the sheathing, is a common way builders aim to combine durability with lower heating and cooling bills.