Hmmm… We just received the following missive from our builder:
“If you’ve been out to the lot, it’s probably obvious the amount of rock we’ve run into. We’ve incurred extra expense, though it hasn’t reached the level of ‘unusual expenditure’ yet. That said, continued problems with rock could create some additional cost.”
The main concern from this point forward is that we might run into trouble when installing the septic system. This includes excavating for the septic tank itself and also running the drain lines for the septic drainfield.
As I noted when I wrote about the approval of our septic permit, it’s possible that the soil won’t be deep enough to provide sufficient separation between the drain lines and the underlying bedrock. Unfortunately, there’s no way to know until they start digging in that area.
If we end up running into problems with rock when installing the drainfield, we may need to add an “aerobic treatment unit” (ATU) to pre-treat the wastewater before it’s dispersed to the drain field. Not the end of the world, but I’d prefer not to go that route. Hopefully it won’t happen.