We're drawing to a close on our 3-day rock removal marathon, and in parts of the pool we're hitting moist clay. The dump truck guy has been saying he thinks we have marine clay (which I don't think, being we're 100+ miles from the ocean, at the very top of a hill, no marine clay marked on the county's soil maps and with no problems with any of the neighboring homes' foundations -- including ours). I'm inclined to think that the soil just hasn't been able to drain d/t all the rock in the ground. So anyway, the dump truck driver has been talking all gloom-and-doom about how we're going to have to dig until we get to dry ground, then backfill with gravel...which could be another week's worth of digging with all the rock we have. Haven't talked to the pool guys yet (I'm honestly afraid to bring it up!), but even if this is expansive clay, doesn't the PB factor this in with drainage and perhaps sump pump, w/o having to dig further? Otherwise, I'm afraid that the excavation is going to cost more than the pool...
moist clay
- Thread starter vapool
- Start date
PB just left...it seems that the developers of our neighborhood, or someone eons ago, put about 11' of fill in at some point. That's what the clay was, and it was mixed with wood and other construction debris, so the "virgin ground" doesn't start til about 11' down. We have to dig that far anyway in the deep end, but now it looks like we're going to have to go that far in the shallow end as well, and backfill with gravel to make the pool stable so it won't crack down the road. So at this point, it looks like excavation is going to cost close to $20,000. 
Ouch, sorry to hear that. What's the developer doing digging 11' down anyway? Was he burying his trash? When we were building our house I was emphatic out no buried trash.
No idea how the debris got down there...we bought our house new, and saw the site before they began building and throughout, and there was never an 11' hole there! This site used to be owned by a quarry, and we were under the impression that it was never used as such, but all I can figure is that they started to dig then quickly called it quits (fortunately, otherwise we could be going down several hundred feet!) Either that, or there used to be a farm house or something there that was filled in long ago. PB was very sympathetic, said he'd never seen both rock and fill like that in one spot and offered to throw in another $1000 toward excavation (he did pay for yesterday, when we thought they just had a couple more hours of work to go). We declined ...it's our responsibility after all, as stated in the contract, but he definitely earned some brownie points with us. I'll upload some pix later...
Here's the progress...most of the stuff in the deep end is loose debris waiting to load into the dump truck. You can see at the very base of the debris the grey material...that's loose dirt right over top of the "solid" ground. You can also see the ramp leading into the deep end is all clay/rock...that all has to come out until we get to solid ground.
I sure hate to see the extra expense you've incurred but....looking for something positive, It sure is indicative you have a good PB that recognized this issue and decide to prepare your groundwork properly rather than trying to mask what may very well have led to BIG problems down the road.
Any construction job is only as good as it's foundation.
Any construction job is only as good as it's foundation.
Yeah, I must say that I couldn't be more grateful that we chose the PB we did. I know that some of the others we were looking at would have most likely just built on the clay. I just keep telling myself that we'll look back on this and laugh someday...
Finally finished digging yesterday (fortunately didn't have to go quite so deep on the shallow end, only about 8 feet or so, and no rocks for the last few feet) and laid gravel today. Now on to rebar and plumbing! Will post updated pix when I get a chance to take pix during daylight hours