Type of Improvement: New Room
A ground-level addition may pay for itself at resale. To add a room with a foundation and crawl space onto the back of your home, work will involve floors, walls, windows, roof, door and interior and exterior painting. To maximize profits, if your home is a two-story, consider making the addition two-stories high rather than one; many of the costs are the same as for a one-level addition. But since value is based on square footage, adding a second floor when already building a first-floor addition means your profits increase substantially while your expenses do not.

• Recovery can reach 90 percent. Be careful not to overdevelop the property for your neighborhood. For example, a room addition that is a third bedroom will be more valuable than a fourth bedroom. A first-floor family room is also a strong selling point.

Type of Improvement: Master Suite
A master suite can be a persuasive element to prospective buyers. By annexing an adjoining area into the master bedroom and bath, you can save the expense of building an addition. The suite might feature a walk-in closet. The bath may require updating to maintain a style consistent with the new suite.

• Recovery can reach 80 percent. To create a luxurious master suite, it’s cheaper to modify underutilized areas than to add on because the roof, foundation and some walls are in place. But if you eliminate a third bedroom in the process, you may find it harder to sell your home.

Type of Improvement: Finished Basement
Basement conversion is usually an inexpensive way to increase square footage. A large basement might be divided into a workroom, gameroom and bath. Features would probably include insulation, painted drywall walls, ceiling and floors. The half bath includes a toilet and sink.

• Recovery can reach 45 percent. Pouring money into a below-grade space doesn’t yield the return it would in other areas of the home. The project might still be a great solution for a young family who plan to live in a too-small house for several more years. Recovery rates are higher for a walkout basement.

Type of Improvement: Garage
If most homes in your neighborhood have garages, you might consider adding one too. A concrete floor, footing, walls, roof, siding, windows and, of course, the doors are included in the average 600 square foot, two-car garage. An oversize two-car garage might also include a workshop and storage area.

• Recovery can reach 60 percent. An oversize garage has advantages if you need work and storage space, but it some cases may over-improve the average home in a middle-class neighborhood. The return on a garage depends in part where you live -- in cold weather markets, buyers demand them.