ᐅ Earthworks Costs for a House on a Slope

Hello everyone,

I have reserved this plot of land, see attachment, and have already received a cost estimate from the construction company. The builder plans to construct a house on a slope on the plot, see picture in the attachment. This costs about 18,000 euros more than a house built only on a slab foundation. Additionally, the earthworks have been estimated at 40,000 euros, including drainage, additional foundation work, etc. Unfortunately, this is a total of 40,000 euros more than I had originally planned. What do you think about this cost breakdown? Is it really that expensive?

Building on a slope is always more expensive than on flat ground, which is why we built a basement.

The soil has to be excavated, etc. It needs to be supported, stairs have to be built, and so on. The 40,000 will probably only cover the roughest part.

I find that quite realistic. We are also building a house on a slope, and in 2019 we paid about 65k for earthworks and the foundation slab. Additional insulation as well as waterproofing against the slope and drainage might also be necessary. Extra costs for us were around 15k (this also depends on whether you are building to a KfW standard, what the soil report shows, and so on). It’s best to ask about these details here. Also, it’s advisable to have an additional buffer since costs can always increase.

PS. In your case, it’s not just a house on a foundation slab. According to the animation, you will have a proper basement with walls in contact with the soil, which can further increase the costs.

An additional cost of around 18,000 compared to a flat plot is possible. The final decision lies with the structural engineer and the geologist.
More reinforcement
Thicker foundation slab
Waterproof concrete (WU concrete)
The wall on the slope side is built stronger than on the flat side
Floor slab

Excavation work varies greatly by region. I do not consider 40,000 to be too much. It is difficult to give an exact figure.

What is still missing is the landscaping. Every change in elevation needs to be managed, and every bucket of the excavator adds cost.

Plan no more square meters than necessary. A basement today can be used as fully functional living space.

Attached is a photo to help you better visualize the scale.

In your case, the road construction will also be at least 0.8 – 1.2 meters (2.5 – 4 feet) higher in the future (see the channels). Yes, building on a slope is at least that much more expensive. It’s already good that the general contractor was honest. There are often unpleasant surprises because of this.