So crushed rock has been backfilled and placed- 4ft over the size of the foundation 26x36 the house but the foundation includes the deck too so its 36x36 of foundation and 4ft arround that 3-4ft deep.
I might repeat myself but heres the reasoning behing the foundation design.
80% of the houses built in the area have moved
some during building- some within a year- all moved within 5 years
Its not frost heave a such- it seems to be caused by the water run off in spring, the sandy silt and clay move and distort during the mud season.
Foundations have cracked in some cases before the house was even completed - one had the deck tear off the house within 8 months of completion
Basicly what supports weight today, may not tommorow, many foundation designs have been completed all under engineers design and signature.
I looked all all common designs and some obscure ones, the last was building on pre installed piles only to find one of them failed too due to lateral movement with some poles moving and some not.
the pre-manufactured foundation -superior walls -house closest to me moved 14" after a water pipe broke on the mountain above.
So I have resigned myself to the fact that the house may move at some point, in order to try and reduce and delay possible movement and its damage to the structure we have employed a few diferent methods
the foundation design is as follows
crushed rock and drains do two things-
the clay sandysilt has been removed down to 4ft deep across the entire area, getting us to more stable soils
The crushed rock cross links and provides a stable platform to build off- providing clear drainage away from the structure and being cross linked extends the support area to basicly 40ft x 40ft for a 26 x 36 house
Drains go to the north and south side of the property.
the foundation its self is basicly a large self supporting tub with stiffening beams in both directions all using #5 rebar throughout, no mesh all overlapping min36"
The reason behind this structure is that even if the house moves it moves in one piece- everything together, no parts cracking or seperating off- both the entry and side porch are all linked to the structure.
Its should all move in one piece, so untill the glasses start moving across the dining table and wlaking to the kitchen seems to be up hill - then its time to either pump grout or jack the dropping side.
hers some pics of the gravel work- the contractor has already built the forms and had inspected by both county and the engineer and they are poring the foundation in one hit- walls and floor together in one interlinked assembly- no joins occur on any corner rebar continous through all the stress points
heres the pics