What do you do when you’ve built as much house as you can on your lot, but still want or need living space?

Move outside. The newest trend in home design is to extend the feel of your home outside and create an “outdoor home.”

Outdoor living spaces are essentially outdoor patios and decks taken to the next – some would say extreme – level. Typically, they include some sort of built-in gas grill, but that grill is often upsized into an outdoor kitchen, complete with running water, refrigerator and freezer, gas burners and ovens.

While many companies sell standalone outdoor fireplaces for a few hundred dollars, outdoor homes can include a fire pit or a built-in fireplace with a hearth in which to bake bread and roast marshmallows and hot dogs.

While most homes have a valve and hose at the back for watering the garden, an outdoor home might include an inground or above-ground hot-tub, underground sprinkler system, pond or waterfall.

Like any construction project, your ultimate landscape plan is limited only by your creativity and budget. Since costs have a way of ballooning in any construction project, make sure you know how much you can spend before you start designing the landscaping project of your dreams.

According to one land planner, a 600 square foot bluestone patio with several levels, a fire pit and lush plantings can easily cost $50,000. On the other hand, you can choose a less complicated design, do the work yourself, and pay only the cost of materials.

Once you’ve decided on your budget, your next move is to think about what kinds of amenities you’d like to have in your outdoor home. Think about your local climate, how much time you actually spend outdoors, what kinds of things you like to do and who the space is for. If you have a growing family, with young children, you may want to create a play space for them that will continue to be fun as they grow up.

What you choose to include is also a function of how much room you have to work with. You might want to have a tennis court, but a singles court requires a space that’s 50’x100′. Some homeowners are building multi-sport courts, turning their tennis court into a surface that can accommodate many different games, as well as be frozen into an ice skating rink during winter.

When it comes to recreational options, balance the cost against how much you’re really going to use it. Many homeowners initially use recreational amenities, like tetherball and tennis courts, but they lie dormant after the novelty fades.

Once you’ve decided what amenities you want, and how much you’ll use it, it’s time to choose the materials you want for the floors, walls, ceilings (if you have one) and other elements of your outdoor home. Purchase landscaping magazines and rip pages out that showcase elements or materials you like, then research the costs by calling local masonry and landscaping companies.

You’ll need a formal design you like before you can begin hiring contractors or planning to do the work yourself. When Leonora started planning her outdoor patio in Highland Park, Illinois, she asked several companies to do a basic plan and budget so she could compare how much it would cost to get what she wanted.

Leonora said the companies did the basic master plan for free, which helped her visualize what they had planned for her back yard. One of the designs was far better than the others, and based on that she hired that company, which then worked with her to make sure the final plan included everything she wanted.

As with any construction project, make sure you know what is going to be included for the final price, including the complete names, item numbers and, if applicable, serial numbers for all materials, appliances, lights, and fixtures. The contract should be in writing, include a start and finish date, and detail the payment schedule. You should not pay more than 20 percent at the start of the job, and make sure you withhold at least 10 percent at the end until you are satisfied with the job.

Before you sign the contract, be sure to call at least 5 references – and make sure they’re not the contractor’s brother, sister or cousin. Leonora says she called "maybe ten references" until she was satisfied she knew all about the contractor. The installation of her patio and garden took two weeks and she and her family find they eat breakfast outside as often as the weather allows.

If you’re going to tackle some, or all, of the work yourself, you’ll need some professional guidance to help you develop the master landscape plan. Talk to your local botanic garden so that you choose the right flowers and plants that will make the finished product look professional enough to give you years of enjoyment and enhance your home’s value.

Black & Decker has published two helpful books under its Outdoor Home series including Designing Your Outdoor Home and Building Your Outdoor Home. Residential Landscape Architecture: Design Process for the Private Residence (3rd Ed) by Norman Booth and James Hiss might also prove a helpful primer.