Construct retaining wall / slope stabilization cost-effectively

Hello everyone,

the weather is steadily improving, so now it’s time to tackle the planning of the outdoor area. Parts of the property are to be filled in. The site has already been surveyed enough that leveling at the lowest point would mean about 2m of filled soil.
On all sides, there are neighboring gardens, which means I will have to build a retaining wall accordingly.

I have already been to the local building materials supplier and spoken with him. He said I should just make a foundation (dig 1m deep, 20 cm gravel layer and 80 cm concrete with rebar) and place concrete blocks on it, reinforcing with rebar and filling with concrete. I should use 26 or 29 cm blocks, but he said he could not provide a structural calculation or advise on that. He gave me a price of just under 3,500 euros for materials only.

Nothing was said about whether a drainage system should or must be installed. I also don’t know where I would lead the water, since neighboring properties border on all sides, or did I misunderstand the drainage, that it directs the water away from the wall somewhere else?

Now my question is whether it might be realizable in another or more cost-effective way? Prefabricated L-concrete elements cost us three times the price here, and they have to be installed with an excavator.

Another possibility I considered is maybe not building the wall 2 meters high but only 1 meter and then creating a steep slope up to the filled final height. But the question here is how steep the slope can be without slipping. The property is supposed to be enclosed later with a hedge that blocks the view. As far as I have informed myself, I have to be 2 meters away from the property boundary to avoid problems with the height, especially since the property has already been filled by 2 meters.

I want to waste as little space as possible to use the property as much as possible, but I also want to keep costs relatively low because many other projects are still pending.
Since I don’t see the wall myself and the neighbor is a kindergarten, the appearance doesn’t really matter to me.

Maybe you have ideas and tips on how I can ideally implement this.

Thank you in advance for your help.

...not to make the wall nearly 2 meters but only 1 meter and then create a steep slope up to the fill height. However, the question arises as to how steep the slope can be without sliding.

< 60 degrees and planted holds.

Hello, sounds like with us, we also had the deepest point at 2 meters, then took hollow bricks, put steel in, poured concrete, and pulled about 35 meters left and right in total.

On both sides, the depth then became less.

Basically, we don't go 1 meter into the ground... only if the soil presses hard.

Would have taken max. 40 degrees. The slope must also be maintained from time to time even with ground cover plants. At 40 to 47 degrees, that is already hard work. I would also install an erosion protection mat.

Privacy screen: you fill up 2 meters. First try how much can actually be seen from below

Thank you very much for your answers.

I googled now because I apparently am too dumb to convert the slope into exact numbers but I think I'm still stuck here :-/

How much property do I "lose" at 60 degrees, in other words, how many meters of distance from the wall to the highest point do I need?


Did you build the wall yourselves and also pour it yourselves with mixed concrete from the cement mixer or did you have a concrete truck come with a hose?
I would like to make the concrete myself for cost reasons but I don’t know if I am underestimating the work.
It would be about 45 m of wall to be built.

What stone thickness did you use and did you have a structural engineer or something calculate the load affecting it so that you use the right size stones?

Do I generally have to install drainage here or can I neglect that?

At 60 ° it would be 60 cm.
At 40 ° it would be 120 cm.

Our new wall, which is also a house wall, has drainage that the old walls do not have.
Consciously, I have not seen any with all the L-beams that are currently being installed everywhere.

Do you have a concrete mixer? With the shovel, you will never feel like you’re finished.