I have been too busy lately to put together a post. However, about a week ago, I did manage this video of final shotcrete prep:
Then we got the shotcrete in and I started on a detailed video with close ups, etc. but it was too long (10 minutes). I didn’t want to cut all the good stuff out, so I quickly put together a second shorter version this evening (with the promise of releasing the more detailed version eventually).
As with every experience, I learned a lot and will write up more details later. The main thing is that I should have spent less time worrying about how flat the lath lays and more time tying the lath to the rebar. I missed tying a few sections and they pushed out like an overstuffed pillow (except with concrete, so less fun). I also learned that there is a front and back to metal lath. It catches shotcrete better if it is oriented correctly. The shotcrete guys really liked the steel studs, but they had me remove the 2″ wide steel strap after the first “lift” of shotcrete was in place. The wider strap was getting in the way and creating a shotcrete “shadow). I’ll put a structural page together on this subject eventually.
Here is a pic of the shotcrete going in. The nozzle man in the back is shooting and the finishers have to follow fairly closely behind before the concrete hardens. The smokey air is like aerosol concrete mist.
This next one is how they handled a 135 degree corner… Sharp on the outside, nice rounded (and over 1 ft thick) on the inside.
As for the final look of the shotcrete, it is a bit lumpier than I expected. The optimist in me would call it “organic”. I expected it to look like a pool (pretty smooth). The shotcrete guys usually make pools and they said they it will, after it gets plastered. I think I will need to grind off some of the uglier lumps first.
Here is a cross section of my the shotcrete around mechanical room. They had to interrupt the spray so we could still get in and out (no doors in a basement wall). some of the thickness variation was sorted out in later lifts.
The cost was also higher than expected. The basement was expected to be just over 40 yards of concrete in the walls. I had originally been told 1 day with 4 guys. Instead, 8 guys worked for nearly 2 days… I expected 6″ thick and got mostly 8″ thick, so my concrete volume was higher. There was also much more waste thru the lath than expected. The concrete price had also gone up (from 84$ to 91$ per yard.) Things were in motion, and the overall cost is still fairly low, so I just rode it out.
In the end, I bought 40 yards the first day and 18 yards the second day (but we dumped several yards each day and ended the job with lots of concrete still in the mixing truck). I still paid less (including steel, rebar, etc.) than I would have for a poured basement with straight walls. But, I guess the poured basement would be smooth finished, and I still have a lot of plastering to do. My shotcrete basement is more than three times stronger than any poured basement.
This weeks focus was on preparing for Shotcrete… The basic studs and lath were up, but we needed to get all the rough electrical and rebar in place. Sherri and I had a lot of work to do.
Here is the video.
The electrical rough-in inspection must be done before the walls are closed up. Usually, that means before drywall, but for us, it means before shotcrete. In our township, electrical inspections are done only during a few specific hours each week, so we had to catch the two-hour Wednesday morning slot or Shotcrete would be delayed to the following week.
I has carefully designed the electrical layout weeks before, and then tweaked it based on Sherri’s input. Now, Sherri and I just needed to work as quickly as we could to place the boxes, run the conduit and then finally, pull the wires thru. We used Carlon ENT (smurf tube) and I had quite a hassle getting all the boxes that I needed. Next time, I will order in advance, but that is another story.
The process took longer than I expected, you can see I am working on it several days the week before. We still had work to do on this inspection day, so we came in very early and got going. We had not been finished long when the inspector arrived. He was very pleasant and actually said he appreciated that we were doing the electrical ourselves. That was a surprise because I expected that any inspector, especially one who was a professional electrician himself, would be somewhat against the idea of home owners taking on their own electrical. He made a few small suggestions for how to keep concrete out of the openings, and handed us our “approved” inspection paperwork.
Next, Sherri and I got going on Rebar. Mostly, I was cutting and Sherri was tying.
At the end of the day, my friend, Nate, arrived to check out the site. He had been up from Indiana for a conference in Ann Arbor. He reminded me that I had first told him about this idea at my dining room table nearly 6 years ago. I didn’t ask if he thought I was crazy, then or now ;^)
Well, this portion of the build is starting to seem never-ending. It is a bit frustrating because I head out to the site with expectations of what I will accomplish and then don’t seem to accomplish half of that. The time-lapse videos help, because, like a sports coach, I can review the tapes. It looks like I am working hard, so I guess the primary thing I see is that I need to reduce my velocity expectations.
Here is the video for this past Friday and Saturday:
Reviewing the tapes (at a much slower speed than the 300 to 900 times speedup that you see) also shows that I could benefit from better organization. I currently spend too much time running to get the thing I forgot to bring with me in the first place… I guess that will improve with experience. Even moving around within the site, I often need to walk a few extra feet to get the tool I just put down. I do have a tool belt, but I hate wearing it. I find it hot and unbalanced. Maybe I should start carrying a small toolbox instead? I could set it down next to me and then move the whole thing every time I move…
On Friday last week, we got a hold of our Shotcrete contractor and made a plan for one week later. We came back on Saturday and put in a long day, but still didn’t get it all done.
I am starting to see the end of my stockpiled vacation days (less than 2 weeks left) and I need to put some days in the office next week, but with the shotcrete date looming, I am going to take Wednesday thru Friday off this week. When I run out, I will need to be more creative. My schedule is pretty flexible and I could do four-tens, or shift to California time or something like that…
One of the things still not done is the electrical rough-in. I have an inspection Wednesday morning, so I will need to get out there for dawn on Wednesday to get it done. Actually, Sherri and I have been working together on it. I am running the conduit and Sherri is pulling the wires through.
I am also talking with several recycling companies to get cheap ridged insulation. It looks like I can get it for about 40% of what I would pay at Home Depot, but I am still nervous about ordering because none of the companies I am dealing with are great about communicating exactly what I will get. Online forums discussing these companies give mostly good reviews, and the prices quoted are quite ahead of my budgeted allotment, so Sherri says I should just go ahead… Maybe I will place the order tomorrow.
