Bumping out or adding a new room can give your house an extra dimension of livability and help create a fresh look inside and out, but adding several rooms can trigger a whole different magnitude of change. For instance, there are limits to the problems you can solve with a one-room project, whereas a multiroom strategy may let you address every one of your home's current drawbacks or shortcomings, especially if your game plan includes revamping some of the existing spaces.
A new family room gives a house extra stretch; a new family room/kitchen wing that includes a full-size laundry area, a mudroom, a first-floor powder room, and a home office makes a home function as if it's a different house altogether. Some large scale home additions do much more than simply overcome shortcomings; they shift a house's focus to a new area or type of space and change its personality inside and out. This is particularly likely if you're expanding and revamping the active areas of the house—main-floor spaces that set the tone of the household and provide a backdrop for various types of gatherings. It's common for a multiroom addition to dramatically alter a home's main axis, shifting everyday activities from the front rooms to the new spaces in back, and maybe even relocating the formal entrance to put it more in sync with the home's restructured traffic pattern and the family's new lifestyle.
To make sure you maximize the potential of your large scale home addition, think broadly in the early stages of planning. A multiroom addition needn't be just a one-level, boxes-within-a-box appendage; it can take any of several basic configurations, depending on the limitations of your budget and your building site. Should you build entirely on one level? Or would the new addition function more efficiently—and fit in more seamlessly—if it contained two or three levels? Should it attach to one wall of your existing house or wrap around the corner? Should it be a direct extension of your house or more like a freestanding structure connected by a transition space (such as an informal entry or gallery)? Should it be a single unit attached to one part of the house or multiple units attached at different spots to address each problem strategically?
As you weigh the practical advantages of these options, consider also how each might deliver some fringe benefits—special new features or attributes that your house currently lacks. For instance, multiroom additions offer great opportunities to generate architectural drama, particularly if the rooms are on different levels or if they include one large space that opens into several smaller ones. Soaring ceilings, cantilevered balconies, clerestory windows, and cascading staircases can give your house a whole new focus—and a new dimension of visual excitement. So can eye-catching vistas, both interior and exterior. Laying out rooms or levels and locating openings in ways that allow far-flung views (in the building profession these are called "through views"), unexpected glimpses, or picture-frame scenes can give otherwise plain spaces a lot of visual punch for relatively little money. They also can make modest-size spaces seem larger.
Don't overlook the potential of leftover square footage—small scraps and slices of space between rooms that usually get ignored or covered up in homes that are built from stock plans. Examples include stair landings, dead space under eaves and staircases, and odd-shape spaces created by angled walls. Depending on their size, shape, and location, such leftovers can be put to work as storage cubbies, eye-catching display areas, or cozy getaway nooks, thus adding character and visual charm that most standard-plan homes lack.
One other factor to keep in mind as you ponder various configurations for your large scale home addition is that the two volumes of space you'll be working with—your existing house and the addition—need to be visually and functionally balanced once the project is finished. The amount of space in a multiroom addition often equals or exceeds that of the existing structure, posing a number of tricky design challenges. Some are aesthetic, some are technical or legal issues, and some involve the day-to-day livability of the new and existing spaces. If your house and lot are fairly sizable and your addition is small by comparison, the balancing process will be easy. But if your lot is small and your house and addition are similar in size, you'll need to rely on good design to avoid creating the addition that ate the house. The challenge will be to make them work together properly and look as though they belong together. What you should aim for, even if you're unable to achieve it completely, is a design that makes the addition look as though it was always meant to be—a solution that makes your house seem more complete now than it was before.
Use these tips to make sure your large-scale home addition is a success.
Maintain the buildable-area ratio
Local codes may limit how much of your lot can be covered by structures (house plus outbuildings). A large addition may exceed the allowable ratio of structure to open space. For more on building codes, go to Remodeling Rules and Regulations.
Coordinate the proportions of new versus existing volumes
Size, shape, and placement of an addition shouldn't overwhelm or upstage the original structure.
Avoid awkward sitting
If poorly sited, large additions or those on tight sites can create long, alleylike spaces next to garages, fences, or neighboring houses. Such spaces are difficult to landscape and put to use. Offsetting some of the new rooms or breaking up long, flat exterior walls with jogs, bays, or bump-outs are some ways to overcome this problem.
Maintain an attractive roofscape
If the addition's ridgelines protrude above the existing structure (a common situation if the addition is wider or deeper than the original footprint) they may create an unsightly hump that disrupts the continuity of the original roofscape. Also, if the roof planes on the addition are more complicated and at a different pitch than those on the existing house, the results may look like two structures shoved together.