ᐅ House with slab foundation on a sloped site

Hello community,
with our first post, we would like to ask for help regarding our building project and would appreciate any suggestions and advice.

We are planning to build the house on a slight slope. The property is 18m (59 feet) wide, with a drop of about 1.5m (5 feet) along this length, which is approximately 8.3% (see sketch from east to west as well as a section of the development plan/planning permission).

To make the best use of the width, parking spaces will be created on both the left and right sides of the house in the form of at least one garage and one parking space/carport each (requirement according to the development plan/planning permission: 2 parking spaces). This way, the setback from the boundary line will be optimized and the house can theoretically be 12m (39 feet) wide. Due to the 1.5m (5 feet) fill, the parking space on the right side will inevitably be lower than the house because of the slope.

Now we are wondering if the fill can be built as shown in the sketch and also be retained flush with the house wall, and if so, how—using L-shaped retaining blocks or retaining walls—and what the approximate cost might be.

Thank you very much

fsbau2019 schrieb:
Now we are wondering if the fill can be done as shown in the sketch and also be supported flush with the house wall; if so, how – with L-shaped blocks or a retaining wall – and what the approximate cost might be.

Do you want to use L-shaped blocks or a retaining wall under the house instead of a foundation?

fsbau2019 schrieb:
To make optimal use of the width, parking spaces for vehicles should be created on both sides of the house, each with at least one garage and one parking space/carport (planning permission requires 2 parking spaces). This way the setback from the boundary is used optimally, and the house can theoretically be 12m (39 feet) wide.

Is a 12-meter (39-foot) building setback from the boundary allowed?

This is a sloped plot and should receive appropriate construction. Where would the road be located?
By the way, it is not just a slight slope.
I would recommend more planning input from an architect and designing a house with a basement. However, without a detailed plan, it’s hard to say much at this point.

ypg schrieb:
You want to use L-shaped concrete blocks or a retaining wall under the house instead of a traditional foundation?

I must have expressed myself unclearly. The ground needs to be excavated by 60cm (24 inches) and replaced with layers of compacted material. This only restores the original level. Then, 1.5m (5 feet) of fill material will be added and also compacted in layers. The question is: how do I support this fill—would L-shaped blocks or a retaining wall around the compacted fill work, or is it even possible to build up the fill like this at all?

What would be a practical alternative for compensating height differences when building without a basement?

ypg schrieb:
Is 12 meters (39 feet) of setback at the property boundary allowed?

Why 12m (39 feet) boundary setback? On both the left and right sides, there is a 3m (10 feet) setback, and the garage should be located at one of those setbacks.

The drawing is a top view, meaning looking into the property from the street. According to the drawing, the view is from north to south. The street runs downhill from east to west, as shown in the site plan.

Thank you

fsbau2019 schrieb:
To make the best use of the width, parking spaces for cars should be created on both the left and right sides of the house, each with at least one garage and one parking space/carport.

I am referring to your mention of left and right... it reads to me as if you want to place a carport on one side and a garage on the other, or vice versa. Both being 6 meters (20 feet) in length would add up to 12 meters (39 feet) of boundary construction, with the house being 12 meters (39 feet) wide in between. Otherwise, your statement doesn’t make sense. My question is whether a total length of 12 meters (39 feet) along the boundary is allowed. In our case, only 9 meters (30 feet) is permitted.

Oh, right,
these 12 meters (39 feet) with one 6-meter (20 feet) garage and one 6-meter (20 feet) carport still need to be checked, otherwise it will be a parking space and not a carport.

ypg schrieb:
For us, it’s only 9 meters (30 feet).

No, 9 meters (30 feet) on one boundary, 15 meters (49 feet) total. In Rhineland-Palatinate, though, more is allowed: 12 meters (39 feet) on one side, 18 meters (59 feet) in total.

fsbau2019 schrieb:
The question now is, how do I support this embankment?

You don’t. Build a basement instead, although @ypg correctly refers to it as a lower ground floor, since a height difference of 1.5 meters (5 feet) is definitely not a “gentle slope.”

fsbau2019 schrieb:
Is it even possible to create this embankment?

It’s possible, but only slightly cheaper than a basement. @11ant has already written extensively about this in several threads.

fsbau2019 schrieb:
The sketch is a top view.

No, that’s a north elevation. A top view would be helpful.