This past weekend we framed the interior walls, and Caleb finished tarpapering the outside. Just in time for rain, too, as we got about a tenth of an inch yesterday. The metal roof and flashing did their job of keeping things dry inside. Yay!

Caleb finished tarpapering the upper part of the wall.

Interior framing, looking east into the shower (left) and toilet compartment (ahead).

Looking northeast into the shower compartment.

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I took last week off, and Caleb and I made rapid progress. We finished framing, sheathed the walls and roof in plywood, got most of the tar paper up, insulated the roof and one wall, and installed the metal roof. Whew!

A view of the framing from the northeast.

I used pressure-treated lumber to frame the shower area. It is regular lumber treated with stuff that bugs and fungus don’t like. Why do this, you ask? The foam insulation I plan to install on the outside of the house is vapor-impermeable polyisocyanurate (building science nerd-speak for fancy foam board). Because the foam board doesn’t allow any moisture to pass to the outside, the building has to dry toward the interior. Since the interior is a humid shower, I wanted some insurance against rot and termites. We didn’t use plywood around the shower, either. Confused? Good. Just know it’s awesomely over-thought.

This is the roof deck shortly before we finished nailing on the plywood. We tried installing the plywood on the roof before installing the plywood on the walls, but the structure was very wobbly. The plywood really provides incredible strength. We were using a nail gun that shot smaller nails than are in the code book, so we had to use extra nails. There are thousands of nails in this little room!

View from the southwest, with plywood shear panels in place.

This is what the room looked like when we called for inspection. The inspector needed to see that all the plywood was nailed on properly and in the right locations. We mostly passed. Which is to say, we slightly didn’t pass. One panel didn’t provide enough shear bracing for the west wall (it’s the one right in front of you, to the left). Long story short, there was some confusion about what I thought I permitted and what was actually allowed. But the inspector was cool and said we could continue, we just needed to show that we had provided adequate shear bracing before we put up drywall.

The roof sheathed and covered with tar paper.

I was glad to move on to roofing. After shooting thousands of nails I was really tired of plywood. The roof is pretty unusual: the insulation is on top of the roof deck. Four and a half inches of polyiso foam over felt over plywood. And steel on top of all that.

The roof covered with polyiso insulation.

The thick foam provides a little more insulation value than is required by code in our area. There will be another six inches of rock wool insulation between the rafters below, making a fairly superinsulated roof. Cozy!

Roof with purlins and metal roofing going on.

We installed the galvalume roof ourselves. A local metal roof manufacturer measures the roof deck and fabricates all the pieces, then delivers them. They provide some basic instructions and loan you a few necessary tools. Installing the roof was pretty easy. There was some cursing over the waste vent pipe flashing, though.

We finished the roof as it was getting dark, so no pic yet. But it’s purdy.

This past weekend I tried to get a head start on framing. So without expecting any laborers friends or neighbors to be able to help, and knowing I’d be out of town the following weekend, I ordered a truckload of lumber and had it delivered. Meantime I got started on sill plates and flashing.

I installed copper termite flashing under the sills. It is supposed to make termites easier to detect by forcing them to tunnel out into the open. It's also pretty.

Between the termite shield and the sill is a foam gasket to stop air leaks.

Some of the anchor bolts were awkwardly placed. Some are where studs should go. This one was a tight fit under the stack cleanout. I couldn't get the sill plate to fit between the top of the bolt and the cleanout. I had to use a grinder to cut off the top of the bolt.

I had to chop off the overhang because the new addition is taller than the room we're attaching it to.

I managed to frame a little over one wall. My neighbor helped do the short wall; the tall one I had to do solo.

I spent a lot of time doing the stud layout. It was made more difficult for two reasons: pipes and anchor bolts. Some of the anchor bolts are where studs should go, as is the greywater pipe for the washing machine. I can’t move the pipes or anchor bolts, so I either have to adjust the stud placement or notch the studs to fit over or around the anchor bolts.

Since the south windows are eight feet up, the view is of trees and blue sky. The window placement is great for passive solar heating in the winter, too.

This is the view from the back patio, with the bedroom to the left. The building on the right is the shed, so you can see there is a sort of outdoor hallway to get behind the new bathroom. I'll put a gate back there to create a sort of secret garden. Don't tell anyone.

We’ve finally started our master bathroom!

We’ve been dreaming of this moment for a long time. Four people in a one-bathroom house is pretty tight. It’s even tighter when that one bathroom is about the same size as most walk-in closets in new homes. Now that we have a permit and have started, we can almost taste the water in the soon-to-be lavatory faucets! I can almost feel the lack of wind in my face from not having to go outside to do the laundry!

We used white marking paint to show where we would remove existing concrete, and to mark the limits of the excavation.

A shot of the bathroom laid out in paint.

We had to dig down below the existing foundation so the new footing would flow beneath the old one.

The previous owner sunk a 4X6 post in concrete. Like, eight bags of it. He used the post to hold up a speed bag. I think he was afraid he might knock it down with a mighty blow.

We had to dig the post out and used a sledgehammer, a heavy bar, and a jackhammer to try and reduce the size of it. We found rebar and copper Romex in the concrete.

We estimated the post weighed around 600 pounds. Caleb is around 200 pounds and would stand on one end of the post, which balanced on the edge of the hole. We managed to roll the post out of the hole, stand it up, and roll it out of the way, The entire time we were dealing with this monstrosity, we kept asking ourselves, why? Why did somebody think they needed 600 pounds of concrete to hold up a post? One 80-pound bag would have been fine.

After we dug the footings, we had to raise the level of the ground inside the building. Because the house is in the floodplain, various levels of government required us to ensure the new bathroom would be 12" above the flood elevation, which happens to be precisely equal to the bedroom floor elevation. So we will have two steps up into the bathroom. Alas, no ADA wheelchair accessible entrance from within..

As we dug the southern footing, we encountered a giant concrete box that had been filled in and buried. I suspect it is the old septic tank, as our house was on septic until the seventies. We also found a variety of abandoned plumbing lines.

We removed all the concrete in front of the back room. We needed to remove most of it to make the connection to the existing sewer line. I also wanted to run a greywater line from the laundry, sinks, and shower to our fruit trees, and that needed to go under the patio too. It sloped toward the house anyway. We re-poured it with positive slope away from the house, and made the back door wheelchair-accessible in the process.

After the plumbers came and went. We have separate drains for sewer and greywater, so there is a lot more pipe than is usual. Arizona is a desert, so it only makes sense to reuse the water from sinks, washing machines, and showers to irrigate the landscape. Arizona has wonderfully progressive greywater laws and incentives so it is easy to do.

The forms are up.

We used a pumper truck to get the concrete all the way to the bathroom. It made the pour a LOT easier and faster than using wheelbarrows.

After a parade of inspectors and concrete guys came and checked everything out in prior days, the pumper truck operator took one look at our forms and said they wouldn't hold. And they didn't. As I watched them blow out, my life flashed before my eyes. It took seven cubic yards of concrete to do the job, and I envisioned a giant useless lump of rebar-reinforced concrete in my back yard. A permanent testimony to my DIY foolery. But it worked out. The concrete guys were awesome. The top stayed square and true, and the finishers were able to strip off the forms and straighten the sides. At the end of the day I had eaten a large slice of humble pie, but was better for it, and everything worked out fine.

There it is! A beautiful finished slab, thanks to an awesome crew of helpers, some professional and some not. I'm looking forward to framing!