Building Up Vs. Building Out , Best Places for Bump Outs,

Building Up Vs. Building Out

Consider the pros and cons of the direction in which you construct your home addition

      There are two main ways to add onto a house: horizontally or vertically. This is often dictated by the purpose of the addition — kitchen additions invariably go out, for example — but it's not always that cut and dry. There's sometimes more than one way to design a project, so consider the advantages and disadvantages of which direction you build, says Curt Schultz, a Realtor-architect-builder in Pasadena, California.

The vast majority of additions involve increasing the footprint of the ground-floor level of the building. That's largely because so many additions are first-floor additions — whether you're expanding the kitchen, adding a family room, or simply live in a one-story home.

What's Involved: Generally, your contractor will bring in a piece of excavating equipment called a backhoe to dig up the yard in the area where the addition will sit, install a new foundation or slab, then construct the walls and roof of the addition before opening up the existing exterior wall and linking the new and old spaces.

Advantages: Building out typically involves the least disruption to the existing space — and to your life if you're living at home through the project — because you're not supporting the new space over the existing structural framing or foundation, says Eden Prairie, Minn., design-build contractor Mark Mackmiller. Also, if you're creating only a small addition, you may be able to do a bump out and avoid any foundation work whatsoever.

Disadvantages: Building out means losing some of your yard, and might even require a zoning variance from the town if you're within the legal property line "setback" (typically 7.5 feet from the neighbor's property). You could also face limitations from the town's Floor-Area-Ratio rating, which dictates what proportion of a lot can be built on (including the house, garage and driveway), according to Roy L. Fyffe, Building Official for Burnet, Texas, and spokesman for the American Association of Code Enforcement.

Building Up

There are many ways that additions can happen without expanding the footprint of the house: You can add another story onto a one-story (or even a two-story) home. You can expand an existing top floor by installing large dormers in a pitched roof to gain useful living space. Or you might add living space above an existing garage, porch, sunroom or other one-story wing.

What's Involved: Although there's no need to give up a portion of the yard to a new foundation for the addition, your contractor will likely have to expose and then beef up the existing foundation and wall structure under the new space to ensure that it can support the added weight. "Adding a room means adding a significant load to all of the elements underneath it," Schultz says.

Pros: You won't lose any yard nor bump into zoning restrictions about setbacks or floor-area-ratio limits. 

Cons: Many towns limit the allowable height for houses, which can be an issue when building up, says Fyffe. If you're adding a whole additional story, you'll also need to account for a stairwell, which can easily eat up around 80 to 120 square feet or more of living space. And your contractor will likely have to tear apart the walls and ceilings in the space below to beef up the structural supports and feed in the electrical, plumbing and heating lines.

Best Places for Bump Outs

Consider these projects as alternatives to building full-scale additions

A bump-out addition hangs the new living space off the side of the house, with no need for a new foundation—and sometimes little or no roofing work necessary either. That can save you 15 to 30 percent compared to a full-scale addition, but you're limited in how big the expansion can be. In general, a bump out can project a maximum of 3 feet from the house and stretch 10 to 12 feet long, says Curt Schultz, a Realtor-architect-builder in Pasadena, Calif. What can you do with a long skinny addition like that? Here are five possibilities:

Turn an L-shaped kitchen into a full U. If your kitchen is wide enough for cabinets on only two adjoining walls, a bump-out addition can yield enough extra space to add a third wall of cabinets and countertops, turning an L-shaped kitchen that's short on storage and work surface into a generous U-shaped kitchen—perhaps even with an island in the middle.

Separate the master bathroom shower and tub. Most older master bathrooms have a combined tub and shower, which is space-efficient—but less than ideal for either showering or bathing. A separate shower means no stepping over the tub wall to get in, plus you can have body sprays all around you. A separate tub needs no walls, curtains or glass doors around it—and it can be deeper than one with a shower attached. A bump-out addition can yield the added square footage needed to separate your tub and shower.

Create a walk-in wardrobe closet. A few extra feet tacked onto the master bedroom might not seem like a lot, but it can be just what you need to expand your wardrobe closet from a cramped pole-and-shelf setup to a full walk-in with adjustable shelving, cubbies and other functional storage options. 

Put an eating area in the kitchen. Many pre-war houses' kitchens are too cramped to fit an eating area. You could build a large conventional addition to accommodate a table and chairs. Or use a kitchen island, peninsula or diner-style booth, which require less space than a table and chairs—and can often be accommodated by a bump out, at a fraction of the cost of a full-fledged addition.

Turn an extra bedroom into a family room. Got a spare bedroom that's underutilized? A bump out addition can turn a modest room into one with plenty of space to serve as a TV room, home office, family room or playroom—or a multipurpose space that serves as all of the above. The money you'll save by bumping out (especially if the room is on the second floor) might just finance the flat-screen TV, computer or built-in bookshelves you'll put in the space.