ᐅ Concrete slab contractor, city inspection report

Kira94 schrieb:

Hello everyone,
our house needs to be built on piles (depth 3.5–4 meters (11.5–13 feet)). No problem, we knew this beforehand. The seller from the prefabricated house company said at the time of purchase that €2,000–3,000 (around $2,300–3,400) is a reasonable amount because the excavator would already be on site and for that money you get a lot of concrete. Now the foundation slab contractor (construction company = partner) says that this is definitely not possible at that price. We have now requested a concrete quote because recently figures in the range of €7,000–10,000 (around $8,000–11,500) have been mentioned. We are unsure what would be a fair price for a slab with an area of 78 sqm (840 sq ft) plus a 50 sqm (540 sq ft) garage. He also wants to reinforce the slab somewhat—but by how much? We also don’t know if 9 or 12 piles including the garage will be enough, as that number is planned for our timber-frame house.
Can anyone give us advice or tell us what costs are reasonable?
Best regards, sonne

We agreed with the foundation slab contractor on €10,000 (about $11,500) for a planned depth of 4 meters (13 feet).
A few more details about the construction site: A company used to operate on this land years ago. The city purchased these old buildings, demolished them, and developed building plots.
All assessments were carried out by the city, which confirmed that all hazardous substances found in the soil were removed and properly disposed of. Therefore, there was no cause for concern, especially since the environmental authority conducted inspections and issued clearance. We knew that the soil had been moved and filled in, which is why the plan was to build on piles.
Now to the disaster: When digging the first pile, after 5 meters (16 feet) there was still no solid ground in sight, and here is the worst part—there was a large amount of contaminated soil, which we suspect is polluted with heating oil.
The city, police, district office, and our lawyer were immediately involved. The construction site is now on hold; analyses and investigations will follow. After just one day, approximately 40–50 liters (10–13 gallons) of liquid had accumulated at the bottom of the pit. The area smells strongly of contamination. Neighbors who have already built their houses are now very unsettled about what might be under their own properties.
Who is responsible for ensuring that appropriate measures are taken, and most importantly, who is liable and will cover the costs of the soil remediation?