There are three project ideas I hear from homeowners again and again--probably because, at first glance, they seem like dirt cheap ways to add space. Alas, all three are far from being the slam-dunks people think they are. They go something like this:
• “We just want to move this wall out a couple feet.” This idea usually reflects the hope that a modest addition will translate into modest cost. Actually, the opposite is true. Expanding a room by two feet or ten feet hardly changes the labor involved, since all the complications found in the larger addition--tying into existing roofs, extending utilities, matching existing finishes, and the like--are found in the small one as well. The actual savings due to the reduced area of floor, walls, and roof is trivial. What’s more, since you gain only a pitiful number of square feet for all this trouble, your cost per square foot goes sky high.
Moral: If you’re going to bother adding on, add the maximum area that circumstances, budget and reason will allow. Small additions do not make for small costs.
• “We want to go up a story.” On the face of it, adding upward instead of outward seems to make sense. The foundation is already done, right?
Not necessarily. In most cases, foundations built to support a one story house are not adequate to support two stories. In the past, building departments have let this problem slide--which is why you see so many older additions of this kind--but not anymore. Nowadays, adding a second story often requires foundation reinforcement or even total replacement, neither of which are minor propositions.
Adding a story also means you’ll need to carve out an area of at least three feet by eleven feet (but probably more) for a staircase, hopefully in a spot that makes sense in terms of circulation. Often, this requires sacrificing a downstairs bedroom, which instantly wipes out the gain of one of the bedrooms you’re presumably adding upstairs. Lastly, depending on the character (and the characters) of your neighborhood, you may risk riling up your neighbors by adding a looming second floor and potentially cutting off their views or sunlight or both. In the past, this was their tough luck, but today, it’s more likely to be yours.
The upshot: If you’ve got nowhere else to go but up, so be it, but adding outward is generally an easier, cheaper, and less disruptive way to gain space.
• “We want to raise the house and put a story underneath.” Usually, folks with this idea are already planning to replace their foundation for one reason or another, so they figure it’s a great chance to double the size of their house in one fell swoop. As you might guess, though, this project has all the headaches of adding a second story and then some. The same staircase problem applies, but now there’s also the additional yet frequently overlooked challenge of getting from the sidewalk up to your front door--which, you’ll recall, is now way, way up in the air. If you’re concerned about resale value, it’s also worth noting that houses with bedrooms beneath the main living area are less popular with buyers than those with more conventional arrangements.
This isn’t to say that these three approaches aren’t worth considering. If the inherent problems are anticipated and properly dealt with, any one of them can yield a perfectly good project. Still, if there’s space available, building a right-sized addition at ground level is usually cheaper and easier.