1. Cover the original slab with new flooring or rugs, or add framing to bring the floor level with the rest of your home's interior.
2. Add skylights, windows, or French doors to brighten the space.
3. Insulate outside walls and roof to increase energy efficiency.
4. If it's too expensive to extend existing heating ducts, consider adding a gas fireplace that's rated as a room heater, a certified woodstove, or a fireplace with an outside combustion-air source.
This modern studio for a husband-and-wife design team started life as an antique two-car garage.
The original garage would turn no heads. But such a freestanding structure offers maximum flexibility. It can become an office, guest house, workshop, or garden room. A hall or covered pathway linking it to the house can create a sheltered compound. French doors can give it a cottage look. Connect the house and garage by removing traces of the old driveway and door.
These owners enlarged the building to include a bathroom, loft, and small roof deck, so it can double as guest quarters.
The new room can also still function as a garage thanks to a set of glass-paneled Dutch doors opening on the plywood-paneled office side. The spare, contemporary style -- the doors, simple exposed-wood framing, visible pipes, and industrial-style lighting -- kept costs down.
Before: With enough land for a new freestanding garage beside their home, Jo and Paul Casterline decided to convert their old garage into a covered outdoor room.
The Casterlines replaced the old garage door opening with a stairstepping wall, then added a long arbor and a center gate. A new gate to the left of the garden room extends the arbor. They opened a side wall facing the garden, building into it a barbecue center and buffet counter of brick pavers.
The interior of the old garage was finished with wallboard, a ceiling fan, downlights, and a brick floor.
The corner contains a Southwestern-style fireplace, complete with a curvy hearth for sitting and a tiered mantel.
Design: Nasrin A. Barbee, Architect, Poway, CA
Before: The building in Aaron Crespi's backyard started life as a small garage. A previous owner did the original conversion, which added electricity, running water, and a shag carpet. After a small fire damaged the building, Crespi decided to make it a guest cottage.
Crespi painted the building the same color as the main house for a unified look. He added a deck, windows and a skylight. A small room with a slate floor at the front of the building creates a sense of entry.
"When I don't have guests," says Crespi, "I like to hang out on the deck or in the house. It's a very harmonious space."
Crespi, a furniture designer and builder, used 13 kinds of wood to build the cabinets, floors, countertops, and shelves. He saved money by designing the building around materials he could get inexpensively. The windows, the sink, and the faucet were floor samples.
To maximize space, he used built-in storage units and added a sleeping loft over the bathroom.