In order for the formwork to be as strong as possible while the shotcrete was going up, I had chosen not to make a hole in the rebar cage for the skylights. Instead, we just built the skylight forms above the steel structure. Now that it is too cold to work outside, it is the perfect time to cut the steel out of the openings and remove the skylight forms.
The Video
The Gallery
Hunter and I were mostly working on different skylights. THis is one of the only timelapse pics to catch both of us in the same shot…
Hunter cut away the steel and then unscrewed the wood formwork. We had built these forms from the inside so all the screws were accessible, but we still needed a pry bar to get some things moving. At this point, the majority of the steel is cut away and the 2×4 structure that held up the skylight buck is removed.
Once the wood and steel were removed, there were some spots where the concrete had not made it all the way to the forms. “Shadows” in shotcrete lingo. This one was the worst of them. I ended up packing these gaps full of hydraulic cement.
Some of the sheets would come out whole… Others were a bit more reluctant and I would need to tear them into pieces, either with a jig saw or just with the pry bar. Of course, this is all done while standing on top of a 13 ft ladder.
In one or two areas it was really difficult to get a grinder in to cut the steel, so I used a cutting torch. My son really wanted to practice with it. I couldn’t let him use it up on the ladder, but I let him cut up a piece.
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…
The video:
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Apse
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.
The Gallery
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.
Snow…
Sherri did most of the lath work during a brief warm spell in February… Sorry, no timelapse.
It was time to shotcrete the central circle of the house. This post is mostly a gallery of pics to tell the story, but first, the video…
The Video
The Gallery
Extra time to add the mudroom roof
The rolled steel arches were welded to an angle iron bracket that was sitting on a concrete ledge and had been tapconned the wall. They were very secure.
Additional #5 rebar pegs were also added to the assembly to strengthen the connection between the roof and walls.
This shot shows the full length rebar spaced one ft from the steel arches and the pegs placed every 6 inches. This pic was taken before the last peg was placed over the steel arch.
This wider view shows the span with the rebar spaced no more than 1ft apart.
Kids love to climb.
They air compressor was helpfull for cleaning the dust off the footings just before shotcrete. You don’t want a layer of dust to contribute to a cold joint. You want the shotcrete to bond as well as possible with the footing and hopefully leave no cold joint at all.
Airial view of the shotcrete equipment setup and our formwork.
Michael and Sherri went around to do a final inspection and get some pictures.
In the background of this shot, you can see the strap I used to pull a stubborn wall form plumb.
Final inspections…
You can see the electrical conduit, etc.
We wrapped the concrete arches to protect them from the shotcrete overspray.
For this job, I got the articulating lift instead of the boom lift… We didn’t like it as much.
Here you can see the first pass of shotcrete and that a whole section collapsed. They came back and filled it in after the other shotcrete had stiffened up a bit.
Even thought we didn’t like the articulating man lift as much as the boom lift, we did like the lift company. We highly recommend wolverine rental.
The final texture was sort of smooth, but certainly not flat. It won’t matter to much since it will all be covered, and at least it was smooth enough to waterproof easily.
Here they are working on the wall in the mudroom. This is why I didn’t want to finish the roof. But once this was done, I could close it off.
David went to get my camera and move it at some point…
End of day 1…
End of day one and we had the north side mostly done.
The timelapse caught this by accident as Aaron was moving it. All the rest of the pics were a tumble of sky and earth, with this one stuck in the middle.
The nearest neighbors house looks quite nice on this fall day. I am sure the view in the other direction is not as pleasant… Sorry.
With the shotcrete only 16 hours old, we started to strip the forms.
Here you can see a closeup on an electrical outlet. The smurf tube did make a bit of a shotcrete shadow.
Here you can see the imprint of the particle board after removing the forms.
Hunter setting up the camera…
Paxton’s son, probably stretching a bit, after all that bent over welding.
Morning of the final shotcrete day… Still a bit foggy at 1000 ft elevation.
In these foggy pics, you can see the mudroom roof is ready to go.
Over the weekend, I also had time to remove the particle board from the apse parapet.
Parapet after removing the form boards.
If I had completed the span across this hallway, the guys would have had to shoot the concrete upward and probably would not have got the wall as solid.
This was the funniest thing… With the weight of the two guys and the heavy hose, they couldn’t get the basket to top back up again. I appreciated that they just went ahead and did the shoot anyway.
This was the minimal bracing that we put under the mudroom ceiling to provide a little extra support. I don’t know that it was necessary or ever took any load, but better safe than sorry.
This is how the mudroom ceiling looked after pulling away the formwork. Of course, we will plaster over this at some point.
THis is the mudroom ceiling after removing the bracing and boards.
