I got a question recently on a post about Remodeling Price Drivers asking:
“When is a bump out no longer a bump out but rather an addition? And when doing a cost estimate, is the cost of a bump out the same as an addition, approximately $200 per square foot?”
The short answer is that, for all practical purposes, a bump-out might cost even more than $200/sf. This is because the bumped out area still requires support and roofing and might require HVAC and other systems. For example bumping out a wall to create a dining nook might only be 3’ deep and 10’ wide – or 30 square feet. It might cost $10,000 to properly support and roof the system plus to add windows and lighting. This would be over $300/sf.
This is the problem with ballpark pricing — without knowing the details it’s hard to provide guidance. In general, very small areas and areas requiring specialized systems or materials (baths, kitchens, etc.) cost more than the average.
The term “bump-out” is, at best, a term of art. Generally, bump-outs refer to situations when a single wall or portion of a wall is extended a few feet. While the space gain might be negligible, the effect can be powerful. A bump-out can transform a flat wall into one of great architectural interest — for example, giving focus to a dining nook. The whole table need not fit in the bump-out but by the pattern of windows or even just by the existing of a slight off-set, the dining nook can take center stage (see rendering below).
In the kitchen, below, one wall was bumped out 5 ft which allowed us to greatly improve the traffic flow and to include a u-shaped kitchen off the family room.
However, both of these “bump-out” are in fact additions. They require foundations or other support, roofs, HVAC and all the other systems required by an addition – albeit a small one.