We are all in need of more space in our houses. When you want an entirely new room–another bedroom, bathroom, or an office or sewing room–you put in an addition. If you still want an entire room but are content if it is not fully functional, you can add a sunroom. Need even less space than that? That’s called a bump out.

You will find little information on bump outs; they occupy a kind of hazy demi-monde in the remodeling world. Full-size addition and even sunrooms tend to get most of the attention. Builders love them because they generate the most revenue. Homeowners love them because they can add appreciable space onto their house in the form of another room, which is valuable when trying to re-sell the home.

The poor little bump out can never be called a room, and as we will see, it’s not even your cheapest option. And there are differing opinions. Home renovation writer Michael Litchfield (In-Laws, Outlaws, and Granny Flats, The Taunton Press, 2011) says that bump outs, in his definition, are essentially in-law suites (full rooms) that are attached to the house.

While not rigid rules, the following provide a general profile for the majority of bump outs:

• Extend from the house from 2 to 8 feet.
• On an upper story, a bump-out can be cantilevered (unsupported by posts) as far as 2 feet.
• Do not require additional heating or cooling.
• Require additional horizontal bracing to compensate for lost studs.
• Typically serve just one function (see below for suggested uses).
• Have a shed (lean-to) or flat roof, rather than extending the existing roof.

Not meant to substantially change the exterior of the house; only to add inside space

A bump out extending three feet from the house, at fifteen feet wide, would in most cases not be considered a major space-maker. After all, that’s only 45 square feet. However, bump outs are often installed in rooms that already quite small. So, a 150 square foot kitchen, when bumped out another 45 sq. ft., receives a space increase of about a third.

Suggested Uses for Bump Outs:

• Provide space for a window seat with bookshelves.
• Allow for installation of a tub.
• Give you enough room in your kitchen to put a length of counter, stove, and fridge. With the increased floor space in the main area, you can install a kitchen island.
• Provides a kitchen with enough extra space to have an eating area.