Hybrid modular buildings offer some degree of customization to modular units for less expense than designing or adapting custom plans by adding panelized or site-built extensions such as such as decks, porches, sunrooms and garages.

Specialty modular design firms are available to guide consumers in the selection and design of a modular building to meet their needs. They are specialists who can design modular buildings from "scratch," adapt the consumer's plans to modular specifications, coordinate all the details with the manufacturers and also coordinate the site work.