Assessment of the offer price for insulation under the floor slab

Hello, we have two offers for a shell construction. Included is insulation under the floor slab. The first one is 6cm WLG038 for €9000 and the other 10cm WLG036 for €2700. The prices vary quite a lot. What would be a realistic price for 105sqm?

From experience, I can tell you that the prices for the material are around 1000€. You can lay it yourself with 2 men on a Saturday morning and then assist the bricklayers while they are formworking the floor slab. At least, that was my deal.

Yes, more like 3000. The other is definitely way too high.

There is hardly anything that you cannot do more easily yourself. I wouldn't want to pay anything for that, except for the material of course. They simply lay a few boards next to each other, thats it

Will probably have miscalculated!?

So apart from the fact that €9000 is absolutely crazy, I wonder what was offered here. Why does one offer 6cm and the other 10cm? As if the planned heights of the building were a wish concert. Who is the planner here and what is he doing?