House with slab foundation on a slope

Hello fsbau

I have to take away some of your enthusiasm: You cannot just stack shuttering blocks and build a house on top after filling. The pressure does not only go downwards. It also goes sideways at a 45° angle. To catch this will mean a bit more than some shuttering blocks, some reinforcement bars, and concrete. I would think of a basement. If that is not an option, the structural engineer will tell you exactly how to manage the support.

Steven

If you do not yet own the plot and a slab-on-ground house / house without a basement is important to you, I advise you to keep looking, since the slope is probably not as trivial in reality as it appears visually.

If you already own the plot, I would still not structure your considerations starting from the building envelope, but first define the spatial requirements and shape of your desired house.

Height data in measuring points would be helpful; contour lines alone are better than nothing but provide a somewhat less precise picture.

Even from the aerial photo

I cannot tell exactly, but if I do not misinterpret the embankment plan symbols in the opening post, the building plots lie in a hollow slightly below the street (?)

Now we ask ourselves whether the embankment can be created as shown in the sketch and also detained flush with the house wall,

Personally, I consider embankments for the hill-ignoring construction of slab-on-ground houses generally to be foolishness, but man’s will is supposed to be his heaven. However, I do put a question mark behind the blissfulness of the idea to shore up house edges with L-stones like with car jacks.

Many things can be done – at least at the price that it may also be a Pyrrhic victory. Fundamentally, an embankment with a house-wall-flush "steep edge" is possible. In the example of the Helgoland coast, this also works due to the rocky ground. With normal building ground, the engineer may find no difficulty, but economically it will not be viable. Whether at least the beauty justifies the effort – yes, for that you would first have to have an idea of the house planned for there.

It is possible, but only marginally cheaper than a basement. has written extensively on this in several threads.

Yes, indeed "11ant basement" or similar will yield a lot of results in the search here

I will summarize what you will find in the sources: basically, I postulate as a rough experiential rule of thumb that from two meters of height difference (within the house footprint area), an "avoided" basement is fully equivalent in cost to a "built" basement, and that this approximately applies linearly in proportion. So, roughly speaking, one can mentally add 10% of basement costs to their budget for every 20 cm of height difference.

As for embankments themselves and their reinforcements, physics is unfortunately cruel and has little humor with vertical (i.e., 90°) slopes. On the free side, the gravity which is vertical by itself is not held in place by any significant counterpressure in the path. Air is far more compressible than any building soil. Consequently, the pressure load shears off. The task of the slope is to resist this. The L-stone essentially achieves this through pressure redirection.

Conclusion: no Frisian would ever think of a vertically limited embankment – no matter how much it may stimulate the salivation of an engineer.

if I am not misinterpreting the slope symbols in the opening post, the building plots lie in a basin slightly below the street level

yes, the basin is about 40 cm lower than the street on the left.
at the right property boundary, it is level. Sloping down in the middle.

possibly a terracing is also possible, so that the fill does not become too high.

set the 40 cm on the left and the house to this level, possibly also 50 cm below street level.
on the right, slope 50 cm. model the front yard terrain so that water can run down the street on the right side of the property.

thus only 3x 50 cm have to be compensated, what do you think about that?

a house with a basement (due to groundwater on the slope a white tank is necessary) for about 50,000 EUR is too expensive for us.

we have chosen a house (prefabricated house), length of the base slab on the street side 10.84 m and 9 m wide.

We have chosen a house (prefabricated house), the length of the foundation slab on the street side is 10.84m and 9m wide.

That means there is a specific desired house model, and you already know the dimensions (before or after floor plan customization?) - then bring it on!

WU concrete is only necessary for the sides in the ground. A basement as living space saves living area. Your prefabricated house on top will be smaller and cheaper. Yes, most timber frame providers talk it down. For structural reasons, they usually cannot build a timber frame in the basement. We had that experience as well. If no money is made from it, it is considered bad. You want to build on a slab Fill for the house, compact layer by layer – with that height bring a load plate test as proof of compaction. Retaining wall. It must not only hold back the 1.5 m of earth but also the house itself. That is not held back by a few rods of steel. How will the terrace be? How will the garden be?

A basement used as living space saves floor area. Your prefabricated house on top will be smaller and cheaper. Yes, most timber frame providers make that seem bad. For structural reasons, they usually can't build a timber frame in the basement. We had the same experience. If they don't make money from it, it's bad.

Exactly, that practically means a basement from the supplier or one where they don't earn anything from it. However, they don't have to bear the terrain modeling effort or include it in their total price. They prefer to pass the buck, and the effort then falls "on the builder".