If you and your home make it past that initial evaluation, you’ll have to decide just how you want to create this second home at your first home. Those factors comprise the main section of the book, where Litchfield outlines the most common strategies. He includes good detail, built around these options:

•  Basement or attic conversion: Working within these existing spaces often means lower overall costs, and this is an option for small lots where a separate building won’t fit. Lighting and ventilation have to be properly handled, and even with a separate entrance, noise and privacy issues may be a concern, and could be better fit when housing family or friends.

•  Garage conversion: Another cost-saving option, with good access for the construction work and perhaps, eventually, for a disabled occupant. If detached, it allows good privacy. You may have to create alternate space for vehicle parking, and the structure will likely need upgrades or modifications to qualify as living space.

•  Bump-out: Given its own entrance, a conventional addition can serve as a secondary residence, keep costs down by using some shared walls, and even provide for a separate courtyard or garden area for the new space. It may crowd the lot, however, and can involve privacy and noise issues, so it’s not ideal for a rental unit.

•  Carve-out: If you happen to have enough existing square footage in the original home, you can subdivide some of it to create separate living quarters. Costs are relatively low, but again the immediate proximity means this is for family members, not general tenants.

•  Cottage/stand-alone: If you have the budget and the lot size, this option provides the most independent arrangement. It can house a parent or adult child, or a rent-paying tenant, and offers the most options for design and layout.

Like virtually all Taunton titles about building and remodeling, the book features plenty of case studies, photographs and illustrations of such projects, good technical information about construction and permit issues, and specific suggestions for materials and methods. This is a valuable guide to territory that isn’t explored much elsewhere.