Monthly Archives: September 2012



Posted on September 29, 2012 by

This is another monthly update.  On the one hand, things have moved really slow this past month, on the other, I am pretty sure I left it too long between updates and have forgotten a bunch of stuff…  I really should bite off smaller updates more often…

Confidence meter

My actual confidence gauge moves slightly slower than this, but this should give you an idea… I worry about time, money and ideas…  But some times, a great idea pops into my head that helps me figure out how to save time and money and everything is good again for a while 😉

There are days when I am so sure this earth sheltered home idea is the best idea ever and I am pretty confident that I will be glad that I took this path.  I am actually pretty confident about the sound principles underlying the earth sheltering concept, but in the end, “the distance between insanity and genius is measured only by success” ~Bruce Feirstein.  I worry that perhaps I don’t have enough money or time or ideas to get this done correctly.  Perhaps I should have designed a much simpler home like BD’s hobbit hole?  Or at least if I knocked the square footage down or dropped some of the fancy ideas, like the storm room tower, I could come up with a more practical design?  For a while there, Sherri and I had this idea of connecting some Quonset huts together in a very affordable way, that was pretty practical.  Were we greedy or arrogant to want something more “architecturally interesting”?  We plan to counter the lofty architecture with simple (affordable) material such as polished concrete floors, but will it be enough?  We have already invested quite some money with the architect and engineer, but that is no reason to keep heading down the wrong path… If it is a wrong path…

Then I will have a good idea or some other moment of inspiration and my confidence level goes up again.  Overall, I have more confident days than days when I think I should probably call it quits and spend the money on something else.  I suppose being overly confident would also be a bad thing…  I know enough to know this won’t be easy, but can I get it done (downward cycle begins again…)


Visit to Battle Creek

The prairie dog exhibit at the Binder Park Zoo was very relevant to my earth sheltered day trip. They let you get much closer than other zoos.

Last month I drove out to Battle Creek to visit an earth shelter under construction.  Since we took the kids (my boys are 6 and 8), we also visited the Binder Park Zoo, I particularly enjoyed the prairie dog exhibit   I arrived at the earth shelter on the last day of the steel being erected.  It was very interesting to see the last 4 steel Ibeam arches get bolted down and tied in with the rebar.

Erecting the Steel

Here One of the homeowners friends is helping to position one of the last steel arches into position. The arches are bolted to brackets set into the floor and connected with rebar placed into the Z-brackets and hammered tight to lock them into place.

I had read a lot about Formworks homes, but it is still interesting to see it first hand and to talk with the homeowner about his challenges.  For instance he had to work out a way to lift the heavy steel into position after his first plan (a rope) slipped and resulted in his wife cracking her wrist.  His final plan involved building a wooden jig that the forklift could easily pick up, but which had lugs to hold the steel directly without letting it swing.  Of course, I took lots of pics and jotted down some notes after I got back in the car.

I absorbed lots of little suggestions like making sure that my shotcrete guy rents his own lift (liability) even if it cost me a little extra, or thinking that if the earth had been piled a little further from the home, it would have been a lot easier to move the equipment around or drain the site.

Some of it was just touching the actual steel, feeling the weight of the rebar was and how flexible the steel Ibeams were over such large spans.  I really left thinking that I could do a lot of it myself (and save a lot of money).  However, there were a couple things I saw that made me rethink some aspects of my design.

Here you can see the bracket, the cold rolled IBeam, and the Z-brackets (one hammered closed). The little white tubes are 6 inch PVC sections set into the concrete to make it easy to place the vertical rebar.

The first was about the importance of the little Z brackets found on the edge of the IBeams…  The Battle Creek home uses a proven Formworks steel arch approach.  Formworks fabricates the steel arches from cold-rolled IBeams.  On the outside of the steel arches, they weld little 1 inch Z clips so you can easily drop rebar in and hammer the clip down to tie the flexible steel into place.  Erecting each one was really very simple with this approach.   Later on in the process, they put 2 inches of insulation on the inside, hooked on the inside of the IBeams.   When they add the spraycrete from the outside, the 2 inches of insulation keeps it on the outer half of the 4 inch IBeam and the cement completely covers the rebar.

We are using steel arches, but our process is quite different.  I didn’t want to do the process of adding the insulation only to remove it again, and I didn’t like the look of the final surface that resulted.  Instead, we are wiring the form work (pegboard) to the inside of the arches, this means the full IBeam is cemented and if we had rebar on the outside, it would not be centered enough to make the engineer happy.  Eventually, I will add a structures section to the website to explain why the location of the rebar is important…  At our last pow wow, we had decided that the only good solution was to drill holes in the steel arches (as part of the manufacturing process) and thread the rebar thru them after they are erected so that the rebar is positioned correctly in the cement.

This is a typical cross section of a Formworks wall. The Ibeams are manufactured with the welded on Z-brackets for easy field assembly. The lattice of rebar is wired to the outside and rigid insulation is installed on the inside as a temporary backer board for the shotcrete… Later, the insulation is removed and placed outside the structure during backfilling.

As I was watching the assembly process in real life, I was trying to imagine how I would manage it with the drilled hole method…  It would be a lot harder to thread the 20′ or 40′ long pieces of rebar than it would be to just drop them in place, and more so if the rebar is bent first.  Also, our drilled hole design does not have any way to lock the rebar in place nicely.   With the Z-brackets, we could just adjust the wobbly Steel until it was plumb and then hammer down the clip to lock it in place…

I was very happy to see these round 1.5″ pipes used as arches. They weigh about 2.2 lb/lft which makes them much cheaper and easier to work with than the larger IBeams (7.7 lb/lft) used on the wider spans.

The battle creek house had two large domes, one 40ft across and one 50 ft across that really needed the strength of the steel Ibeams to carry the load.   However, it also had some narrow vaults (12ft?), which were similar to the span I used in my design.   My second big discovery was that the Formworks engineers had specified that they be built with only 1.5 inch steel tubing.  Formworks has designed many earth sheltered homes, so I trust the experience of their engineers.   Those relatively small tubes could be huge for my earth sheltered home.  First of all, the steel tubing is much cheaper than the 4 inch IBeams, both to buy and to bend.  They would be much lighter and easier to erect also.  It also occurred to me that switching to the 1.5 inch bent tube would also solve my assembly problem by letting me use the Z-brackets.  If I tied the forms to the inside of the steel tubes, I could still use the Z-brackets to hold the rebar and it would be at the right depth in the cement.

I decided that I would need to talk to my engineer about it.  I prepared a nice ppt presentation with images, etc. (I have not yet got permission to share the pics I took there on my website) and sent it to them on Sept 6th, but have not heard back.

I plan to head back out to Battle Creek when the shotcrete work is done…  And then hopefully again for the waterproofing…   It is amazing to me that the giant 50ft clear span domes only calls for 4.5 inches of concrete…  and will support an earth load that is 3ft deep at the top of the dome…  Between the domes it will be more like 15 ft deep.


Design Team

The plans have not really been updated very much over the past month (or two).  I have got several drawing sets from the architect because I asked for weekly updates, but it is often hard to find many changes.  Each time, I review and send back a list of the new issues I have found.  Sherri thinks I should skip the emails and just phone them.  I did that a couple times, but I like the written record.  At the moment, the architect seems busy with other projects, so I am far ahead of them in terms of reported vs resolved issues; but when they finally have time to get around to it, they should be able to go thru all my emails and check off all the changes in a straight forward way.  I figure it is easier/better for everyone if the issues are written down.

One of the main unfinished aspects of the design was the storm room…  It was just a rough sketch when I got to the architect, not modeled up nearly as well as other aspects of my design.  The architects put in a place holder design when we got started, but never got around to focusing on that area, even to their own satisfaction.   Functionally, the tower is really a solar chimney for the house, but I also wanted to be able to sit up there with a 360 degree view and watch the storms roll over.  It didn’t need to be a big room, but I wanted a hole in the floor to let light down into the rotunda below.  I didn’t want to run the stairs thru the hole because it would clutter the rotunda (originally designed as a central hub of my home) and block the light.  We moved the spiral stair outside the rotunda, but the storm room was two small to run the spiral all the way up into the room.  As a work around, my early design (going in to meet the architect) had involved a switch from spiral to alternating tread stairs part way up.   However, when I saw they way the architects drew it (the shifted the alternating tread stair quite a distance from the spiral), I didn’t like how discontinuous it was and started to consider running the spiral stairs all the way up.  This would not be easy because the storm room is centered over the rotunda (not centered over the stairs) with a radius that doesn’t quite reach the stairs.  Running the spiral stairs all the way up would either require a much larger radius or changing the shape of the storm room (round to egg shaped or with a bump-out) so the stairs will fit.  A week or two ago, Sherri and I re-evaluated our needs and decided to go back to the alternating tread stairs, but try again to get the architects to start them at the top of the spiral stairs so they would be more continuous.  I sent that to the architects, no response yet.  If this last paragraph seemed like a lot of back and forth, that is just how it felt in real life, but stretched over 6 months.  I am interested to see how the story ends.

This drawing is a work in progress with a number of features missing and changes to be made… However, it does illustrate why I can’t just continue the spiral up to the tower… You may also get the hint that we are not exactly going for the simplest earth sheltered design we could think of…

As for the engineer, I have not seen anything yet, although I have asked about it.  At one point, well over a month ago, he had done some preliminary calculations on some of the required reinforcement and determined that “it works”.  A few weeks ago, I summarized a list of half a dozen questions I have asked the engineer over the past few months, but none have been answered.  I guess we would be pretty silly to pay another bill without seeing some of what we have already paid for.  I am hoping something will come thru any day now.


Not much in going on here lately.  I got some quotes on doors.  Sherri is working on getting us an address.  We never heard back from that plumber Sherri mentioned in her earlier post.  I called him after a month, he admitted he hadn’t started yet, but said he would take care of it within a day or so.  I have not heard from him since.  I am working with Pella directly on windows pricing…


The website is now past 3000 visitors   It is getting interesting as I am getting real messages and even email at my “” address.  I am getting mail from across the USA and as far away as India.  I added a hit map on the right hand side of the screen to track it.  The free version only tracks 30 days worth of hits, and only collects the data under certain circumstances (shows fewer hits than Google Analytics), but seeing things on a map like that is very interesting.

This past month, I got comments and e-mail from Adam Bearup, somewhat famous to me because of his “earth shelter project Michigan” videos on Vimeo.   The best video is this one about shotcrete…(watch it if you want to get an idea of how our cement will be applied)  We sent some mails back and forth about his experience with earth tubes and I added a bit more info to that section of the site.

I also updated the soil temperature experiment (the temp 10 ft under my property is quite comfortable at this time of year after soaking up heat all summer) and some of the ventilation stuff.

Of course, I still don’t think my site is anywhere near ready…  I want to add info on structures, systems (heating, water, electrical), waterproofing (beyond what is already in the umbrella section), etc.  At some point, the site will be “good enough” and I will mention it on Facebook,  Twitter, etc. and use my Google coupon to to spread the info further than that.  Of course, that will all probably be much closer to the start of construction and the journal part should get more interesting.



This week, I have my first test in my Cost Accounting MBA class…  I had already used many of these methods in estimating the cost of my home, but it is good to see things defined and and my methods verified.  Maybe I will add a section to the site about that.  But first, I study.