The great thing about relying on natural light to brighten a house is that you're dealing with just one, permanent source-the sun.

The house's floor plan was laid out so that the master bath suite, on the first floor, shared a wall with a hall bathroom. The second-floor bathroom was situated right above the hall bath. The house was a Cape Cod, so there was also a knee wall beside the second-floor bathroom, and the rafters rested on the exterior wall plate of the first-floor master bath.

In a quirk of fate, the floor joists happened to run the length of the house rather than across it. That meant Crigler could put a vaulted ceiling above the first-floor bathrooms. By dropping a skylight into the shared ceiling, both baths were lit.

Then, to spread sunlight into the second-floor bath, Crigler replaced the knee wall with glass block. Now, a little light goes a long way.