ᐅ From what height difference are L-shaped retaining walls / barriers required?

Hello everyone,

We are currently planning the groundwork on our purchased plot, and one of the questions is whether the terrace should be level with the house floor or if there should be steps leading down. We would prefer to raise the entire garden, including the terrace, as high as possible since a lot of topsoil will be excavated during the groundwork and can then be redistributed. Also, the house sits relatively high, so raising the terrain makes sense if everything—floor, terrace, garden—can be on the same level.

However, this would make our plot higher than the neighboring property, and I would like to know up to which height difference work can be done “simply and cost-effectively,” and from when it becomes more complicated, for example requiring L-shaped retaining walls.

Alternatively, two levels could be created so that the terrace is still at the same level as the house (referring to the finished floor level), and from the terrace a step down leads to a second level that aligns with the neighbor’s property height. This would mean some topsoil still needs to be removed, but it might be cheaper than raising everything and using many retaining walls.

Here are a few numbers for a better idea of the heights:

Finished floor level: 62.46
Current ground level in terrace area: 61.47
Height at boundary with neighbor: 62.20

Of course, the whole situation is more complex, and the groundworker and later the landscaper will need to plan and measure in detail, and there are more sides of the house involved. But I just want a rough idea as this is important for the groundwork as a basic terrace preparation—whether the terrace will be at a height that allows a step-free exit from the house or if there will initially be a significant step down. We want to avoid steps for aesthetic, practical, and other reasons, especially since the house is quite high and there will be a lot of topsoil available to potentially raise the entire garden to this level.

Thank you and best regards!

What does the architect or builder say about this? There are also regulations regarding allowable height adjustments that must be considered.

Did our Henrik once again try to save money in the wrong place?

I am currently planning and designing our outdoor area, and I can tell you one thing: try to minimize any retaining work as much as possible.

I have about 40 meters (130 feet) that I want to level on a corner lot. The height difference is around 1.5 meters (5 feet).

At first, I considered using timber sleepers, but when I think about it, the sleepers alone cost around 10,000 euros plus the foundation. Then there’s the labor, because installing sleepers is nearly impossible given their weight.

1-meter (3.3 feet) granite timber sleepers from China cost about 20 euros per linear meter (just under 7 dollars), one-third of which should be set in the foundation.

The concrete foundation material for 40 meters (130 feet) would probably cost around 1,000 euros.

An alternative is using concrete blocks, which you can install yourself. One block costs about 1.5 euros. It doesn’t look great and should be plastered, but over the years the plaster may start to peel off.

@HilfeHilfe: What do you mean by “cutting corners in the wrong place”? So far, no one knows about our planned expenses except us. We are at a stage where the elevations have been established with the architect, civil engineer, and surveyor. It is now fixed how high the house must be in relation to the flood protection level (backwater level) and therefore also the height difference between the starting point of the terrace and the current ground level, as well as the neighboring property’s ground level.

I am probably a bit early with these thoughts, as you usually only consider these details when the house is already built and all the heights are precisely determined, etc. Still, as asked, I would like to understand in principle what can be done.

As I said, I don’t understand your comment at all, and you can save yourself the trouble because it is completely misleading. So far, we have only purchased a plot, and nothing has happened apart from the surveyor’s work.

@tomtom79 – I don’t understand how your statements relate to my post, I think you are comparing apples and oranges – if you need to provide support or reinforcement, then you have to do it, and there are many ways to do so...

I have shown you two options along with their costs, so you might be able to draw some conclusions from that.

What are the total costs per linear meter? That way, it’s easier to compare, including both materials and labor. So far, I’m assuming about an 80cm (31.5 inches) height difference for L-shaped retaining walls. I believe you only need bollards or posts for larger height differences, but I could be wrong.

Therefore, a direct cost comparison would be helpful. I think there are quite a few options for supporting a terrace at an 80cm (31.5 inches) height difference...