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

Burial Phase 2

0

Posted on October 1, 2017 by

 

In the previous two segments, we put dirt over the shotcrete and then added our waterproof insulating umbrella.  In this segment, we put an additional layer of dirt over our umbrella, then plant grass and work on the retaining walls.

For your viewing pleasure, here is the timelapse video…

Video

Lessons learned

  1. As always, not everything makes it into the videos.  One part that didn’t quite make it was adding the layer of blocks along the top edge of the wall above the back door.  That wall is an ICF wall, basically 6 inches of reinforced concrete poured between two sides of insulation.  We put a good amount of blue max waterproofing on the top edge and then I made sure that the billboard vinyls (17 mill reinforced)  also overlapped the edge and I mortared 3 layers (about 12 inches) of block along the top edge to hold it all in place…  I thought this would be good enough.  However, water finds a way…  It was able to get between the ICFs and the concrete and run down the inside of my wall all winter…  I’ll need to tear those blocks off and put in some continuous metal flashing at some point.
  2. When we started laying it out, I assumed that the experts would know what to do.  Of course, they were pretty uncomfortable with my not having a detailed plan, but were nice enough to work with me. So, the first lesson learned was that I really should have come with a plan and not put that on the contractor.  As it turned out, I really didn’t bring enough blocks to for that back wall.  Some sort of math problem. So that was my second mistake.  The compromise solution was to turn the blocks side ways and lean them back against the hill…  I know this is not ideal and I already expect a lot of negative comments on Youtube.  I decided the only way to overcome that was to put a lot of concrete and rebar behind the blocks to tie them together and form a continuous dam.  This chewed up a bunch of time, but it is over a year (two winters and two springs) later and the wall is so solid that the mortar hasn’t even cracked.

 

Other tricks up my sleeve

Sherri was concerned that someone would fall off that boulder wall, in fact, she always calls it the “death wall”.  She insisted that I put a rail along the top and bottom edge.  I wanted that rail to be as slender as possible and decided I could use copper pipe for posts and rails.  This isn’t against code if I don’t put a walking path within 6 ft of the rail.  When used as the posts, the copper pipe would be much easier than a wooden post to attach to the boulders…  Just drill it in.  The problem is that it wasn’t really stiff enough.  I found that “L type” copper pipe was quite a bit thicker and stronger, but I still wouldn’t want to rely on it.  I also found that 1/2 inch L copper fits almost perfectly inside 3/4 inch L copper…  This made it more than twice as stiff, especially if I filled the gap with epoxy…  So that is what I did.  The last problem was that the holes were not drilled perfectly vertical (that is harder to do than you might think), so you see they are a bit off plumb at the start, but later we were able to bend them vertical.

The Gallery

Here are some pics, mostly just old scenes since this wasn’t really a photogenic stage.  Enjoy.

 

Adding the Umbrella

2

Posted on September 16, 2017 by

In the previous post, we added the first layer of dirt over the home.  In this next step, we add the “umbrella” layer to keep the first layer of dirt dry and warm.  The umbrella is made of layers of rigid insulation and billboard vinyls and topped with a pond liner and carpet.  Of course, I’ll try to give you some details into the practical construction of this umbrella, but first, the timelapse video.

The Video

Not so easy

When I read John Hait’s book oh PAHS (Passive Anual Heat Storage) he talks about coming up with the umbrella idea because it made it easier to cover the dome in insulation.  So I guess I thought it would be the easy part and didn’t really put as much pre-thought into the install as I have for other aspects of this home.  However, I was very wrong.  It was not easy and don’t let the video make you think it was.

The first challenge was getting the pieces to stay where you put them.  This was hard enough on the flat spots and only got more and more challenging for the steeper slopes.  I tried a number of things like using wood stakes (I used my table saw to cut a 2×4 into wood weges that were 1/4 inch thick and 6 inches long and pushed them into the sheet to give it traction).  The stakes helped with the first layer, but I couldn’t use them on the second.  Tape helped a little, but was often foiled by the tiniest amount of sand or moisture. I even tried sliding the insulation between layers of vinyl, but that was difficult to do precisely.

The second challenge was getting the shapes all cut just right.  It was enough of a hassle to cut away for the skylights, etc.  But dealing with trying to fit rigid rectangles to the compound curvature of a hillside as the sand shifted under your feet was incredibly frustrating.

Then we added the billboard vinyls, which wasn’t too bad.  Gluing them with the HH-66 was also pretty straightforward.  But once the vinyls were on, the insulation became more difficult to manage. If the underlying layer shifted, it was very difficult to get back exactly how you wanted it (butt jointed with no gaps).  It also became much much harder to add the next layer of insulation.  Even walking on it was difficult in the steep areas and we kept sliding off.  Normally, I would have considered the slide as fun, but it wasted time and messed up the insulation again.

Getting the giant heavy pond liner up there (hardly shown in the video) was also a challenge and dragging it messed up the underlying vinyls and insulation.  Pretty stressful actually.

Then the carpet layer helped…  It was pretty good in terms of ease of install and its weight actually locked in the underlying layers pretty well while also making it easier to walk around.  Most of it was in pretty decent shape and some of it was even brand new (trimming from an install?), but some of it was gross.  I recall one had fingernails and other nastiness on it as if it had been stripped from a repossessed home where the evicted tenants were not big on cleaning (I assume people that disgusting were evicted ;).

Regrets

In the end, I had a few regrets.

Primarily, I wished I had put a bit more insulation right up against the vertical sides of the building.  It would have been easy to add it there and I wouldn’t have had to worry so much about it after the dirt was added and those steep sections were just so much harder to insulate.

I also wished I had dumpster dived for a couple more carpet loads.  It was clear to us that carpet prevented erosion.  We only had erosion in the spots that had no carpet.  You could see that the erosion stopped in nice square shapes along the edges of the carpet layers.  We ended up coming back and adding carpet to those spots, but it was much more work later then it would have been before adding the final dirt.

I am not yet sure if I will regret not putting more insulation.  As I said, it is about running out of time and money.  Did I insulate enough?  Was it thick enough?  Did it go out wide enough?  Even John Hait says he didn’t think he went wide enough.  I think I am OK there, but wonder if I will regret not spending a bit more on insulation at this stage.

Silt Fence

The silt fence was a county requirement with a fine of several thousand dollars if it wasn’t installed after excavation.  The regulations include that it should be installed correctly, which requires a trench first so the bottom of the fence can be buried to actually catch any silt that runs off the site.  To do this, there is really nothing better than a little tractor with a plow.  I highly recommend it to save hours of annoying digging.

One other pro-tip is to screw a piece of scrap wood as a furring strip to the stapled side of each post.  Those staples don’t last long and it is much easier to add a strip of wood now that will hold the fabric in place permanently.  Or maybe you prefer to go back and fix the fence every few weeks.

Gallery

A gallery of pics…  A bit light for this section because no one was feeling like taking pics and it was also difficult to get any good angles on the umbrella anyway.

Burial, Phase 1.

1

Posted on September 9, 2017 by

Our earth-sheltered house design uses an “umbrella” concept to retain the heat and keep things dry.  This post covers the first phase, the dirt under the umbrella.  Still, it was a big step.

The Video

The Gallery

Often the story is best told with pictures anyway…

1 2 3 4 5 48 49