Construct retaining wall / slope stabilization cost-effectively

And I have to say, we are usually the do-it-yourself type. But something like this is simply a bit too much and more for professionals. I really did some serious reading up on it and at least for our case came to the conclusion that we need professionals (statics, backfilling, drainage, foundation, etc.). It should last as long as possible so that you never have to worry about it again, but instead other people do it in 100 years or more.

We are facing a similar problem. Our wall is about 50m long and roughly the last 15-20m need renovation. Since the property slopes slightly, the wall is 1.2m high at the highest point and gets lower towards the front. Behind it, there are old privet hedges and shrubs everywhere (city property, with a sidewalk next to it).

So far I haven’t found a feasible and affordable solution. I have come to terms with the thought that we simply have to spend a lot of money one day and commission a large company. The wall is 100 years old and over about 8m length it already leans slightly inward and the plaster is falling off everywhere, so it won’t stay good much longer. Since our property is quite narrow at the back of the garden, I have abandoned the idea of setting a slope. We would definitely lose too much land there. Plus, you also have to support what was there before. You can’t just casually tear down the old wall…. at least we would be facing quite a bit then. We also have the problem that you can’t get a car close by, at least not with larger vehicles. Considering how many tons of material are needed, doing it ourselves is downright crazy. You need real manpower and machines. To make things worse, there is a street lamp, so we first have to get the location plans of the power lines from the civil engineering office.

I’ll be honest; such projects are really not fun; neither financially nor in terms of effort.

The street lamp can be dismantled. Our municipality arranged that. Dismantling, transport, storage, and reassembling were, I believe, around 3,000 euros.

The slope must be retained before the wall is replaced. It might be cheaper to build a new one in front. I wouldn’t do it myself.

The issue with the statics is overrated. Our house was built on compacted soil, then we had a slope and built the retaining wall (highest point 2 meters) and then filled it with earth.

What should press there?? When the house was already standing on the ground??

Also this thing about having to go 1 meter into the ground and frost-proof etc.

My father was a bricklayer, he laughed about it. He said just dig a 30 cm deep trench, 20 cm for gravel which you compact + first concrete layer, then set the first stone (10 cm in the ground / 10 cm above the ground)

Then you do it like Lego, always staggered.

As I said, it was fun, you just need someone who knows about plumb so the wall doesn’t get crooked over the long straight...

That was the only challenge.

the static stuff is overrated. [...]
what should be pressing there?? When the house was already standing on the ground??

In retaining wall discussions, I always feel like these are meetings of people who have never seen a landslide after heavy rain and have only covered a bit of optics and electricity in physics class.

One side (supposedly) solid mass (plus potential energy) and the other side only air: of course that presses - even if the internal strength of the mass "resists" (only then not dramatically). If it gets too wet (or experiences comparable influences), being rock solid and tipping over is still the bravest thing the wall can do.

Theodor in the football goal still holds, and the hairstyle with Three Weather Taft as well, but unfortunately the wall only holds up in father’s previous experience.

Three things help here, preferably in this triple-combination: anchoring (which is also what L-stones do), inclination against the direction of pressure, and "reinforcement" (of the pressing mass itself!) with root systems or the like.

Reinforcement in the wall does not make it strong, only stiff. That is good and useful as a fourth measure but does not replace the first three. The stiffness of the wall only makes the difference between crumbling and tipping over. Because crumbling requires lower forces, which make the forces visible, laypeople tend to believe that stiffness is supposedly sufficient except for hundred-year events.

Forces often only become evident when one side becomes more than equivalent to the other – nevertheless, to deny their existence until then can still be a sinful offense.

I dare to claim I can quite accurately tell by looking at retaining wall builders whether they are physics teachers, business economists, or computer scientists.

Very well explained. On our wall, you can see what happens when you just botch it like that. Water and frost eat through causing decay through the wall, the wall begins to lean, plaster falls off (even the plaster that was once renewed simply falls off again in large sheets) and even individual stones just break. So everyone has to decide for themselves, but in this case, I am definitely in favor of doing it right from the start.

On our wall you can then see what happens when you just botch it like that. Decay eats through the wall because of water and frost,

But you are probably talking about a wall made of mortared bricks - that is a whole different class - I was rather referring to walls made of formwork blocks, where this development does not apply compared to pothole genesis, and the phenomena you described do not occur in this way.