The day after shotcrete on the perimeter walls, we got started on prepping the steel arches and setting them up for another round of shotcrete. This particular apse is special because it will eventually be my office (where I will spend most of my waking hours), and because it needs to be in (along with its retaining wall) before we can bury the garage side of the house. The work was all pretty simple compared to the bedrooms, and I didn’t take much time to stop and take pics, so this post should be short. But first, the video…
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An apse is the semi-circular end of a vault. They are pretty common in earth sheltered homes because they can hold a lot of load, but usually, they are at the back, completely buried. I put mine up front and included a window. Hopefully, it turns out to be a good idea. This apse will also be my office, and I spend a lot of the time on video conference calls, so hopefully, the acoustics are OK. At least my head will be near the window and not near the acoustic focus point.
This is how the guest room looked the morning after shotcrete.
It looks warm enough in the pics, but the temp was probably less than 40 and freezing over night. I left this propane heater in the room to keep the roof warm while it cured.
I was pretty happy with how the mud room roof turned out…
This is the top of the playroom apse. Because it was out in the open, it also needed its own little parapet wall…
Hunter checking on the camera as he flipped the steel arch. He had welded 3 sides of each leg, but needed to flip it to weld the 4th.
Positioned the first arch here and took a quick pic just to get an idea of the scale of the office…
The office apse steel at the end of the first saturday…
Here I am looking quite grizzly, but happy things are working out.
Office apse with mostly just the horizontal rebar.
Michael messing with the camera… He likes moving past it very slowly so it looks like he is moving normal speed and the rest of us are high speed.
Snow stopped our progress for a couple months.
Sherri did most of the lath work during a brief warm spell in February… Sorry, no timelapse.
For some strange reason, I have always wanted to build a block wall. So of course, I had to work at least a bit of that into the plans. I chose to build the bathroom out of block because it was all internal walls and I liked the idea that it may slightly brace the quonset hut before we added concrete over it. We also had this idea that the garage would be finished first and it would be great to have a bathroom in there so we could use it during the rest of the build…
Also, I have often joked (only half kidding) that I would like the bathroom to be waterproof so we could clean it with a power washer. And that would require no drywall…
First, the Video…
Glass Bottle Wall
I have also wanted to make a glass bottle wall for a long time, but with a low R value, they are not practical as an exterior wall in Michigan. Instead, I plan to finish the gap between this bathroom wall and the Quonset ceiling with glass bottles… This way, it will be an internal wall and will let light in from the garage skylights while still finishing off the bathroom wall to the ceiling to provide privacy. Video to come later… much later. Maybe after we move in.
1) Buy half blocks, etc. When you go to price the blocks, you will find that the full 8″x8″x16″ blocks are pretty cheap. In my case, they were 86 cents each. But then if you look at half blocks, you will find that they cost almost twice as much for half as much block. At first, I said, “No way, those are for suckers, I’ll just split the full blocks.” And while it is true that some of the full blocks come designed to be split, it was not easy and I wrecked half the blocks that I tried. Eventually, I realized that those half blocks were expensive because they were worth it! I also bought 4x8x8 blocks and cut those in half for some quarter blocks.
2) Pay for delivery. Blocks are heavy and it took hundreds to make even my small bathroom. You could make a bunch of trips with a pick up truck (be careful not to overload it), but for the money you would pay in gas, you could just have them delivered all at once and without risking wear and tear on your vehicle. Delivery also saves you time, and time is money.
3) Cut the blocks for electrical as you go. I guess we were just so excited to be building that we forgot to do that. When I came back later, it looked pretty easy in the video, but… If cutting the block had cracked it, how would I have replaced it? It was also pretty challenging to get the ENT boxes to fit in the holes with the conduit attached to the tops, and then I had to run the conduit and wires all the way up to the top of the wall and back down again, which wasted a few extra dollars. Plus, you just look silly for forgetting.
4) Make sure your concrete dye is a nice liquid or powder so you can mix it accurately. Mine was a lumpy semi-solid mass that had been sitting on the shelf at Home Depot well past its expiry date and this made it very difficult to get a uniform color. I found that I could blend the color by wet sponging the wall later, but it still doesn’t look quite right.
Here are some pics from along the way…
This was the plan for the bathroom. The shower plumbing was supposed to come up in the wall, inside the blocks, but it was placed about 6 inches off… We discussed how to adjust the bathroom to fit and ended up moving the ind wall back another 8 inches, so things ended up a little bigger than this.
Get your blocks delivered. They are heavy and delivery is cheaper than all the trips it would take to carry these safely in my pickup truck.
Sherri waiting patiently for me to setup the camera
Blocks at the end of the second evening, before the bond beam went up.
Before the bond beam
View of the door buck and scaffold inside.
Laughing about something… Sherri has water in her bottle with a pin hole in the top that she was using to help smooth out the walls.
Michael helping out on the inside while Sherri and I finish up the outside.
Half done the inside, and I am leaning back to adjust the camera.
Sherri finishing up surface bonding the last wall
A view from the inside…
I had accidentally touched up some of the outside with lighter cement from the inside (see above the door), oops. I decided to try and smooth it out.
The surface after sponging to smooth out the color and texture.
I installed the toilet flange with a hammer drill and some tapcon screws. Easy.
Brand new toilet… Oh the horrors it will see.
After the walls and door were in, we could add a toilet…
While the trench was open, it was our chance to lay the drain tile and earth tubes. We didn’t set the timelapse and we were too busy working to take many photos, but it is an important step for any earth sheltered home, so I want to capture a few details. Sorry, no timelapse.
We had already laid the drain tile and earth tube close to the house as we back-filled that portion. Click here for that story. But we still needed to run long tubes from the house to daylight.
The bottom of the trench was already sloped to 1% and the septic line, made of 4″ schedule 40 PVC, was already in place (done by the excavator and already approved by the plumbing inspector). We needed to bury it, but with a constant slope. Sherri and I used shovels and rakes to pull down dirt and bury the original line by about 6 inches. We (and the boys) stomped on this layer to pack it down, especially next to the buried septic pipe. The end result was a nicely sloped flat bottom trench.
We connected 100 ft long segments of 6″ corrugated drain pipe to the ends of the pipe we had already buried up by the house. We used a proper fitting connector piece and also taped it heavily and covered the connection in landscapers fabric. We laid these two parallel drain tiles along the trench and periodically placed dirt on them to even everything out and keep them separated by a couple feet. I would have liked to have separated them by more, and I did where the trench was wide enough. In all, we added about 150 ft of pipe to each end of the drain tile loop.
Normally, a drain tile loop is connected to a single long pipe that runs to daylight. However, by connecting each end to its own pipe, I am able to use it as an earth tube circuit with an inlet and outlet or two inlets. The other end of the pipes goes into the house, but I can simply connect those ends together if I want the air to circulate under the mass of the house without entering it (by-passive annual solar heating). The extra cost is the additional 150 ft of pipe, which cost me about ~$100.
The second layer of earth tubes was the 8 inch double wall (smooth inside) HDPE pipes. These come in straight 20ft segments that have a bit of flex to them. You can connect the pipes directly (bell and spigot ends with soil tight connectors) or you can connect them with 30 or 45 degree joints. It was a hot day and we did not have the energy to properly bury the 6″ corrugated drain tile before laying the larger earth tubes, so we decided to mount the larger earth tubes to the side of the slope (with stakes) a couple feet above the previous layer. This still left more than 10 ft of earth above these pipes for most of the distance and gave us more than 6 ft between the two parallel pipes.
At the end of the day, we had 4 earth tubes, each over 150 ft long, going from the house to “daylight” along the trench.
The next step would be backfilling.
Later, while back-filling the trench, we made sure that the 8 inch pipes stayed in place while the excavator back-filled below/between them and the 6″ pipes… This took some care and probably added at least an hour to the back filling process. The excavators charged by the hour, so that should probably be counted in the cost of the earth tubes, but seemed like a bargain compared to backfilling that trench manually on that hot day. I did pull out some of the stakes when they were no longer needed to hold the pipe still, but many were buried in place at an additional cost.