More than half the businesses registered in the U.S. are now home-based. But few homes are designed and built to accommodate them.

Most contemporary housing is designed solely as living space, without the demands of work in mind. People who work out of their homes are left trying to resolve conflicting needs in a single space: a business that’s open to clients on the same site as a private living area; a noisy workspace in proximity to places where the family needs to study, relax and have down time; potentially dangerous...