You may be contemplating an addition tacked on to your house. But additions do not have to look “tacked on.” Other design strategies exist to expand and enhance your home functionally and aesthetically, to increase space or to make better use of existing space.

Also don’t assume that an addition must be a stylistic clone of the host structure. This can be the right strategy, but it is not the only strategy. Some additions work very well through aesthetic contrast rather than analogy. An artfully composed addition can harmonize visually with an existing house yet not replicate or mimic its stylistic language, materials and details.

The shapes of many houses and other building types readily lend themselves to expansion. But if a building’s form is geometrically balanced and unified, or complexly sculpted, adding a new piece can be awkward. Likewise, expanding a landmarked edifice subject to historic preservation standards is always a challenge. Tacking on an addition to Frank Lloyd Wright’s Fallingwater or the National Gallery of Art East Building would be very problematic.

In designing home additions, talented architects will always explore diverse alternatives after first analyzing project parameters: the client’s functional needs and lifestyle aspirations; the architecture and history of the house; the site and surrounding neighborhood; and, of course, the budget.

Consider the following alternative approaches, some obvious and others not:

Addition by analogy or contrast (Roger K. Lewis)

Enhancing without adding on. Your house may feel small and function poorly because of its layout. And enlarging the house could be constrained by zoning setbacks, landscaping or a desire to preserve the house exterior. Thus, a makeover of the interior might be the only option. Perhaps the need for additional interior space can be met simply by closing in a screened porch. In any case, interior reconstruction entails demolition, structural modifications, new partitioning and new finishes, plus new mechanical, plumbing and electrical work, which is why this strategy is the most disruptive for occupants.

Tacking on. Adding a new room or a new wing extending into a rear yard or, occasionally, a front one is the most common approach for enlarging a home’s volume and floor area. Expanding vertically by removing part or all of the roof and adding a story also may be feasible. But raising the roof can be logistically and structurally complicated, and it can adversely change a home’s scale and proportions. No matter how it is tacked on, an addition can be designed to be expressively different or to look as if it was always part of the house.

Stretching. Some houses may be stretched by increasing the width or length of the whole house, thereby preserving the home’s basic character. I stretched my own seven-level house to make it six feet wider by outwardly displacing its long southwest facade and enlarging all the floors behind the facade. The same stretching strategy was used to expand Dulles International Airport’s main terminal.

Enveloping. If an existing house is especially small, dysfunctional and unattractive, architects can intentionally transform the existing house by completely absorbing it within a new structure. My firm once wrapped an existing house in a new skin because increasing floor space and improving the layout required reconfiguring and enlarging interior spaces around the house perimeter.

Adding an accessory building. With a sufficiently large site and budget, a client may ask the architect to design a free-standing, structurally independent addition to meet client requirements. An enclosed gallery, a covered breezeway, a terrace or deck, or little more than a stone wall and a paved walkway can link the accessory building to the main house. This approach works well for guest accommodations, swimming pool pavilions, work studios or garages.

Perhaps the most important thing to remember about expanding your home is to keep an open mind and avoid “one-size-fits-all” thinking. There may be a design solution that has not occurred to you but, once explored, proves to be the best of all possible solutions.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland. His cartoons may be seen at .