House Demolition Costs - What to Pay Attention To

I want to have a two-family house from the 50s/extension from the 60s with a footprint of 8x10m, 10m height, approximately 110sqm living space with a concrete high cellar that goes 1.20m underground demolished. In addition, there is a 100sqm large concreted courtyard. According to my calculations, 164t of concrete, 130t of bricks, 3.5t of wood plus smaller quantities of various materials including 0.5t of glass wool and 4.4t of black brick slag. The roof underlay membrane of 100sqm is asbestos-free according to testing. I have not detected any other pollutants.

Now I have received different offers, which mainly vary widely in disposal costs, and some are flat-rate offers without any breakdown. For example, one wants €13.5/t for concrete, another says it is not pure concrete and charges €40/t, with similar price differences for the bricks. I am not really satisfied with any offer yet.

Who has already had a similar demolition near Ulm and can recommend someone to me?
Who has ever had a demolition at all and can tell me their offer, preferably also by private message, so I can get a feeling/comparison.
What should I absolutely pay attention to???

If I were you, I would take a look at the all-round handyman / janitorial services / Oleg&boleg Bau UG on eBay Classifieds and have them come by. We found one here with his own screening plant and crusher. He takes all that very cheaply and then installs it as RC under the pavement for other customers. He is always very grateful for concrete, but you can hardly build with Ytong and brick gravel...

Where do you currently end up with the costs?

Between 20-50k€ everything is included, very different offers

If I were you, I would check out the all-purpose craftsmen / janitorial services / Oleg&boleg Bau UG on eBay Kleinanzeigen and get them to come by.

We found one here with their own screening plant and crusher. He takes all that very cheaply and then installs it as RC under the paving for other customers. He is always very grateful over concrete, but with Ytong and brick gravel you can't really build well...

The thing with the crushing plant is a good idea. Do you have their address, I can't find it right now.

It won’t be pure concrete anyway, but reinforced concrete, which also weighs more than 2t/m³. If someone now gives you an offer with just concrete, they are really going to reach deep into your pockets when it comes to the billing. With anything other than a flat-rate offer, you can really fall on your face. 20k€ for such a house would be very cheap – 50k€ is actually reasonable.