Information about design and construction of earth sheltered homes and a journal of my own progress

First Electrical Inspection

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Posted on August 6, 2014 by

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 ;^)

Never Ending Build

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Posted on August 2, 2014 by

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 (Michigan Shotcrete) 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 stock piled 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.  On line 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.

Overnight work party

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Posted on August 1, 2014 by

This week included an overnight work party at the property with some friends, Aaron and Ryan.  We headed out after work on Wednesday and got in a few hours working on the window well until it got a bit dark.  Then we had a nice camp fire (using my rocket stove) and talked until past two in the morning.

The next day, we got up before 7 and worked on Rebar until they had to go mid-morning.  At 9:00 AM, my N-12 pipe arrived and I was glad to have my friends there to help me unload it.

N12_Pipe_Delivery

After they left, I tied rebar for a while, then spent a few hours on off camera tasks like getting new tires and parts for my skid steer.  Eventually, I got back and spent the rest of the day on Electrical.

Here is the video.

Extra Info;

XPS forms?

I wanted to use a different approach for forming the window well…  Partially because I wanted to experiment with different methods and partially because the window well is more exposed to the environment and I didn’t think the metal lath and studs would be a good idea.  I originally thought I would just do it with plywood sheathing and 2x4s.

On the way out to the property, we stopped to pick up a trailer full of wood at Home Depot.  Sheathing Plywood is actually pretty expensive.  More expensive than tongue and groove 1” rigid XPS insulation…  So we switched plans on the fly and bought the XPS instead.  I also considered going with OSB, Oriented Strand Board), and bought a couple sheets, but didn’t use them.  The XPS was easy to work with and I am pretty happy with the decision.  The test will be when we shoot the shotcrete at it.  XPS is tougher than the EPS backing that I saw used with shotcrete last year, plus it is firmly attached to treated 2x4s, so I think it will be fine.

At the end of the day, I think the XPS and 2×4 approach was easier to assemble.  However, it is also more expensive, especially if you are building forms more than 8ft tall.

Curving rebar?

For curving the rebar, we tried a few things, including the rebar hickey.  The main difficulty is getting the right curvature and all in one single plane.  Bending rebar is easy, curving rebar to a precise shape takes technique.  The winning solution is shown in the video.

We stand on the rebar and pull one side up a certain amount (experience helps).  Basically, it is not really a continuous curve, but more piecewise linear.  When the raised end becomes two difficult for one person to manage, one person holds it vertical (in plane) so the other person can do a similar bend from the other end.  Due to the way that steel stays in the elastic range for a while and then yields for a permanent bend, we need to over bend it to start.   So the second step is to push it down flat, again keeping it in plane.   (an improvement I worked out on a later day was to walk it flat instead of using our hands to wrestle it down).  When we let it go, it springs back to a curve with a larger radius.

StressStrain

We had marked the radius we wanted in the sand and we set the curved rebar in the sand “template” to check it.  Some of them were right on.  If they needed any adjustment, one of us would stand at the point where things started to go off the line and the other one would pull the rebar horizontally and adjust it into shape…  The adjustment is actually so fast and easy that the timelapse camera, with a 10 second period, didn’t catch us doing it.

Electrical

Carlon Smurf ConduitThe electrical takes longer than I thought I would…  I have a plan that I am referring to, but actually wresling the blue Smurf tube (ENT conduit) into position thru all the right holes is a bit tricky.

Also, my plan didn’t take into account how many tubes would leave each box and their directions.

NEC code prohibits bending the ENT by more than 180 degrees along its length.  Each box is attached to a stud.  In many cases, the stud blocks one side of the box and leaves only 3 knock outs for the conduit to attach to.  These are in a chain, so a light switch needs one pipe to carry electricity in and other to continue the circuit to the next switch.  A third tube goes vertical toward the ceiling where we will eventually put the light fixture.  Ideally, the third tube would come from the knock out at the top of the box.  The problem happens when the power is coming from above (such as over a door).  If I run it down and around to the bottom of the box, it would exceed the 180 degrees of bending that code permits.   Instead, I must run it into the side of the box and run the “out” tube from the bottom of the box even though it actually needs to go sideways…  What if I also want to branch my circuit in a second direction?  Anyway, it takes some head scratching.  I will shot for an electrical inspection next Wednesday.

Sourcing

AA_Promo_1When you walk into Home Depot, there are lots of big signs about ordering online.  This is because they don’t have everything in the store.  For instance, none of the rebar tools on the Home Depot website are actually available on the shelf.  However, it also helps for buying cases or quantities not available in the store.   If you buy individual outlet boxes, they cost about 2 dollars each.  If you buy them in bulk, you can get a case of 50 for $38, that is about half the price.  But you can only buy the case on line.  Also, for some reason, the stores only stock 100 ft lengths of ¾” ENT tube.  The ½” tube costs quite a bit less, but only comes in 25ft lengths, and if you buy 4 of those, it costs more than the ¾” ENT tube in the 100ft roll.  The only way to get ½” tube at a good price is to buy a 200 ft roll on-line (which costs just a little more than the 100ft roll of ¾” tube).  Get it?  Good.

Problem is that it doesn’t always work out right.  I ordered a case of 50 outlets.  It was 1 case, so the quantity was listed as “1” and the amount charged was ~$38.00.  I chose to pick it up in the store.  When I went to the service desk to pick it up, they had set aside one single box for me…  I showed the girl my smartphone with the email showing I had been billed for a case, but there wasn’t much she could do except put it back as if I had not come in to pick it up.  They didn’t have any in stock at that store.  I ended up driving to two other stores in different cities trying to find enough boxes to finish my job.

I got an email today saying that if I don’t pick it up soon, the order will be canceled, so I guess I don’t need to do anything.

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