In 2020 I renovated the small building in our backyard which had fallen into disrepair. It was zoned for use as a home office, and had electric but not plumbing. I wrote about how I was thinking about insulating it and comparing framing options but then apparently I never got around to writing up how I finished it!

I hired someone to replace the roof:

Doesn't look like I have a picture of the top, but it's rubber membrane.

I hired them to put in a window as well. If I'd realized how much space would be lost to casing I'd have asked the mason to make a larger window hole.

Plans for the walls and floor:

Covering the walls and floor in 2" foam:

Anna helped:

The floor is one layer of OSB, then one layer of plywood, screwed to each other but floating:

Vapor barrier around the top, and 2x3s the flat way to attach the drywall to. I used fiberglass batts to insulate the roof:

One more layer of foam, around everything.

Help from Lily:

Drywalling it all:

Casing the old windows. This was annoying since nothing was quite square.

Finished!

A major thing I liked about this house project is that no one was depending on it being done at any specific time, so I could work on it when I had free time.

Now one of our tenants uses it as an office, and we rent it for $400/month (utilities included). The total cost (ignoring my time) was $17k, and utilities might be $500/y, so if we're able to rent it continuously the payback period is 4y.

It's nice to have more usable space!