My guess is that the backfill swelled either from moisture in the clay or from freezing.  Certain types of clay can expand enough when wet to cause damage.    Clay can trap moisture that could freeze in your climate.

By the way, what angle was cut on the hole for the basement?  For example were the earth banks left vertical (90 degrees) or sloped at 60 degrees?  Angled banks will allow for slippage when the backfill expands, especially if the backfill is clean gravel topped off with about a foot of clay.  Clean gravel allows the water that penetrates the top layer of clay to fall to the foundation drain.

If we can understand what caused the problem, then maybe a fix can be determined.  Local contractors should be much more knowledgeable than someone like me from the southeast U.S.

Posted By Jusolson on 20 Dec 2013 11:00 PM
The Panels are a "SIP"  The manufacture is Enercept.  We actually toured the plant where they make the panels.  The basement panels rest on a concrete footing like any other building would.  They used a pretty thick water proofing membrane on the outside, and I have seen zero water other than the sump pail.   The panels are 4' wide then after placing the panels two top plates are fastened on top of these, then floor joists, ect...  The sides of the hole where pretty much straight down, definitely not angled.  I agree in hindsight maybe the use of a course gravel would have been better.  I wish I would have known to look for movement before it froze to know if it was occurring before the frost.  My big concern is if it is going to continue to move, or after these first few winters/ cycles this will be it.  I want to finish the basement in the next few years with maybe sheetrock next winter.  If this continues, it will cause cracked sheetrock, and limit my access to view/ monitor it.  I feel like the house so far is solid, as I have not observed even a slight crack in sheetrock upstairs anywhere.  Even if the fasteners where inadequate from the top plate into the panels, the question about HOW to remedy it remains.  Here is a pic before backfilling on the south east corner

Posted By eric monkman on 25 Dec 2013 02:49 PM
Personally, I would not lay any blame at the feet of your builder as the choice of building systems was yours.
SIPS are DIY friendly and the majority of concrete work requires a high overhead and equipment burden , so the choice for SIPS and PWF in the hands of DIYers is easy to make :-)

Remedial requires you to dig up the perimeter and backfill with lightweight fill. This is an excellent way to get rid of your ICF foam scraps etc.

Posted By eric monkman on 26 Dec 2013 08:51 PM
Chris :
The backfill used in this situation is overloading the the SIPS installation.

In addition wet weather can add substantially to the soil weight if it is not free draining.

If the SIPS system cannot handle the load to which it is being subjected, it is therefore a poor choice.

The person responsible for the design of the structure should have taken into account all the variables.Soil density, lateral backfill pressure and structural integrity/limitations.
Lateral backfill tables are included in most high quality ICF Product Installation manuals for example.

SIPS above grade are an excellent choice, but below grade not in the same class as ICF's. Nothing is perfect :-) imho

You will find that EPS foam fill is used extensively to reduce backfill weight in many circumstances in Roads, Bridge approaches, and Residential applications.

Posted By Jusolson on 04 Jan 2014 12:39 AM
Hi everybody, thanks again for all the discussion. I thought I'd give a quick update as I met with our builder the other day. He came out to basically look it over himself so he could understand what was going wrong. This builder has been in the business, 25+ years, done numerous SIP houses ( even his own personal house is SIP with SIP basement) and said he has not seen this kind of problem at all. He said that sometimes he sees a wall bow in a bit from the pressure, maybe 1/4 -3/8", but the top plates along with the floor truss would flex some, but not like this problem. His initial concern is if those top plates were fastened correctly to each vertical stud in the panels. He was just spit balling ideas, but maybe heavy screws would have to installed at each stud to help. He couldn't really give me any concrete answers/ solutions right now. He was going to get in touch with the SIP manufacture to see what they have to say. So I'm kinda at a stand still as far as answers/ course of action. I brought up a soils engineering report and he was not oppose to that. He also thought that this would have happened within a short time after backfilling, I'm not so sure, and we have no way of knowing anyways so I guess its moot to argue. He said that they have always used the soils on site and haven't' had problems, so I'm the lucky one. I mentioned I have no problem digging it out to repair it, but he said that it would be hard to push the walls back out to correct the deflection, at least not the ones that have only moved maybe a 1/4", but might gain a little on the one wall that is the worse ( 3/4" - 1" ). Other than that he didn't say much, and I made it plenty clear that I was not happy and want a solution. He understood and never objected. So like I said... wait and see.