So all the excitement over the change order had us back up and re-evaluate the concrete subcontractor's method for building our concrete footings.
The foundation plan at the east walls was to build deepened footings with tall cast in place walls in places. However, the height of the cast concrete wouldn't exactly be known until we had dug down to an area of natural soil called "formational." This formational soil is the base of where the house footings sit per our soils consultant information and recommendations. Granted, we had some idea of the depth of this - but the depth actually exceeded our assumptions by about 36". In the end, we had dug a 36" wide by 60" deep trench along the eastern edge of foundations to get to good dirt, but the cost of those extra three feet far exceeded what we expected.
When we got the change order, the concrete subcontractors gave us a blanket statement that a cost increase was due because of heightened cast concrete and larger footings. Yeah, but how did they get to that cost increase?
It became clear that our concrete subcontractors had overlooked the plans and the soils report which indicated a footing depth that was required to be at least 7' measured horizontally to "daylight" of the existing slope face. In talking with them, they at times said the soils report "didn't matter" or that they anticipated the footing would be typically 18" below grade... a total denial of reality. This kind of talk was mind blowing to me. That basically meant that overlooked not just three feet high of additional concrete - but something more like six feet! In volume, that meant about 200 cubic yards of pure high strength concrete that needed to be accounted for. In the subcontractor's mind, that meant 30% additional cost to their bid.
After settling down and talking with Mr. Builder, we both determined that the change order wasn't going to be agreed to at all. The only problem was finding a cheaper solution to our trench problem.
Fortunately for us, Mr. Builder is resourceful and remembered some earlier discussions about using slurry concrete to "connect" with the solid formational soil that our footings are supposed to rest on. Slurry concrete is cheap, rough and gravely - not pretty or attractive, but it gets the job done of acting like compacted soil which most footings typically sit on. In addition, slurry can excavated in a manner similar to compacted soils. Our soils engineer likes it too.
Within a week of getting hit with show stopping change order, we have poured slurry and are making new progress.
