Under-stair storage makes a good deal of sense – after all, what else could you possibly put in an area with such odd ceilings and shallow depths? As it turns out, a bathroom may not be a bad idea for this otherwise awkward area found in virtually any two-story home plan.
Showers, sinks and mirrors may be tricky, but bathtubs and toilets do not require full standing height to work, since they can be lain in or sat on respectively. Tiny and cramped is also a bit more acceptable for a bathroom than it would be for most any other heavily-used area of a house, since its uses tend to be short.
That said, there are many ways to ‘do it wrong’ too – insufficient lighting (artificial or, ideally, natural as shown in the photo above) can kill any space, and a small one all the more quickly. Try to put too much in and you can make a cozy washroom feel more like a (water) closet.