The Envelope House is an urban infill project in a seemingly forgotten residential neighborhood of Seattle. A zoning change to allow multi-family housing left an aging bungalow on the site dwarfed by larger, nondescript development. The owners’ desired to maximize the investment potential of the site by replacing the bungalow with a flexible multi-family structure that challenged the architectural character of the neighborhood. The 30’ x 112’ site with 17 feet of grade change required the design team to think outside of the box as they sought to understand and re-interpret the financial and regulatory constraints of this project type.