ᐅ Excessive Excavation, Oversized Foundation Pit

Hello everyone, we are building a single-family house with a basement. So far, so good. Our building inspector already mentioned during the pouring of the foundation slab that the excavation pit was dug too large, resulting in excess soil being removed. Of course, the costs for backfilling will also add up later. The invoice for the excavation arrived, and it shows about 80 tons (approximately 88 short tons) too much. Is there any chance of a credit or adjustment? The soil has already been disposed of, and the excavation contractor is also responsible for several other trades, so we definitely don’t want to completely jeopardize our relationship with them. How should we proceed?

Best regards

Unfortunately, this has become common practice nowadays. I guess the gravel pits get a 50/50 share.
Of course, it would be more sensible to address this directly. Was everything hauled away? In our case, although far too much was excavated, we left a large pile on the property until the end and only had it removed later. We were still able to reuse a lot of it.
I would normally ask the excavation contractor why so much was dug out and why everything was taken away. He should be familiar with the dimensions of the house.

80 tons probably corresponds to around 60 m³ (79 yd³) of compacted soil in a basement. For a working space, that means about 15-20 cm (6-8 inches) more space around the house, which is really not much.

What type of soil is actually required for the foundation of the concrete slab?

We use filling sand, suitable for compaction