Houses are like snowflakes—no two are exactly alike. Each house has its own unique features, one reason I find real estate endlessly fascinating.

More than 35 years ago, I bought a small, simple house near the Hudson River and began to make it my own home. It's a process that's still unfolding, a continuing, hands-on transformation that has taught me much about the houses: their appearance and their infrastructure, aboveground and underground, in...