To call it a guesthouse would probably be to oversell it. I call it the writing shed, or just the shed. My parents call it the casita, but they like to be fancy. The previous owner used it as a backyard shop, a 12-by-20 building where he milled all the woodwork that he used to do repairs in the house. It’s a simple structure on a concrete slab — or it was, before we tore it down to the studs. There’s no proper office in the house, no real guest room, and even before we moved in, we decided that we’d do whatever it took to remake the shop into livable space. We did almost all the work ourselves. It’s still simple. It’s just — well, maybe it is a little fancy now.

We hired an architect to tell us how to vault the ceiling without the roof falling down. We lifted the floor, floated hardwoods on pressure-treated stringers, hung drywall. We put an antique window in the gable. We matched the trim and finishes to those inside the house, hung cedar siding on the outside, and painted the interior walls a very, very, very light gray. I grew maybe unhealthily interested in getting the color exactly right. Ten different cool white samples later, I confess, it was tough to tell the one I’d chosen from the primer.

Having a guest room is nice, I’m sure, but I tell you this with love in my heart for our guests: It is a good and lovely thing to tell somebody “good night” and send them off to their own space, their own walls, their own quarters, if you will. There’s a coffee maker out there. When the weather’s right, we light a fire in the woodstove. We fold towels for the tiny bathroom we added during the renovation. If we have time, we make the two futons, turn the covers down. If not, we leave clean linens, ask forgiveness.

Maybe the best way to think of the place is as a folly, a cabin, a little half-secret space that spends a handful of nights a year as a guest suite and devotes the rest of its time to incubating novels. Both my wife and I work out there. It’s a great place to hide from kids and dogs, and a fabulous spot to read during a rainstorm. Our boys moved into the shed a couple of summers ago in a furious act of secession — and we let them. They lived in it for a week. They were a little sorry, I think, to move back inside.

I often leave the desk light on, even when nobody’s in the building. The kitchen windows look out into the backyard, directly at the heavy leaded-glass double doors that my buddy helped me hang, a job so miserable that I knew, even as we were doing it, that I wouldn’t be able to repay him. The glow through those doors is a soothing one, though, reminding me that even as much as I love the house, there’s a place here that’s separate, a place where we can let people hide from us when need be, a place where we can hide from ourselves. We’ll probably never get all of our money back out of it, but that’s OK. We’re not moving anytime soon, and the shed’s not an investment, anyway. It’s more of a security blanket. And the walls, which are either Arctic Hare or Kilz, are gorgeous.