Unplanned retaining wall

I received the offer for the wall today. €22,300, so over 50% of the land price again. Bitter.

It refers to:

4.5m wide, 2.8m high
6.5m wide, 3.2m high

The height is L-stone measurement.

Everything included except for a railing and surface covering.

Can someone tell me if the offer is reasonable? I am, of course, shocked by the figure.

Talk to the building company, maybe they will give you some leeway, or their craftsmen will do the wall for a better price.

Unfortunately, you’re the one who gets the short end of the stick in situations like this. It was similar for us, just with the roof. Talk to the company, maybe they will contribute so it isn’t too severe. However, you will probably be stuck with the main part. Then I would also get another quote. Companies differ wildly in price for earthworks and support works. Check how much L-bricks (reinforced) cost in these dimensions. If you’re already at 15k there, then the price isn’t too bad. If you really need those sizes, that’s quite a chunk of money.

Ask other companies for a quote. Our retaining wall costs 7k net for 68 m², locally shuttered including reinforcement. Since the company is also carrying out the base plate, garage, and earthworks, I do not know exactly what other costs are included in the other items (site setup). Slope protection during the construction period is not necessary for us. We place the new wall in front of the old one.

Shouldn't such an inspection have been the first thing to be done? I think as laymen, we builders cannot be expected to assess whether such a wall is sufficient or not. Who is to "blame"?

The inspection should have been carried out by an expert commissioned by one of you. Of course, a note from the construction company would have been nice, like 'if the wall is no longer in top condition, this could cost a bit more'. As the builder, you are responsible for everything that is not explicitly contractually assigned to someone else. It's not nice, but that's how it is. I would still hire an expert to check the load-bearing capacity of the retaining wall. The casual statement from the construction company would not be enough for me. What else you can do is to obtain counteroffers.

You can also build a wall from formwork blocks or planting blocks. This is cheaper than a classic wall.