ᐅ Filling the site for a concrete slab foundation

Created on: 2 Jun 2019 23:28
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Bauvorhaben20
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Bauvorhaben20
2 Jun 2019 23:28
Hello,
Unfortunately, our plot slopes downward and needs to be filled by about 80cm - 1 meter (31 - 39 inches) at the lowest point for the foundation slab.
We have not yet spoken with any civil engineers or excavation contractors. Could someone please explain how the ground is filled for a foundation slab, what materials are typically used, and what costs we should expect?
The floor plan measures 11 x 10 meters (36 x 33 feet) plus a garage of 8 x 6 meters (26 x 20 feet).
Thank you very much in advance.
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Jenpa
3 Jun 2019 07:46
Have you had a soil survey done? This will also determine how load-bearing your ground is.
Do you have the elevation survey? This shows the terrain profile and the relevant high points.
In my opinion, both are absolutely necessary before approaching an excavation contractor. Ultimately, what starts as 80–100cm (31–39 inches) might turn into 140cm (55 inches), which raises the question of whether to include a basement.

Similar to our situation: We are building with an architect, and two different architects recommended building with a basement. They suggested using the “lower/shallower” part of the plot as an office and guest room (which also gets good natural light from larger windows) and instead reducing the house’s footprint. The additional cost compared to a slab foundation is about 25,000, but that gets you a full basement. For us, it’s worth it.
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vx220
3 Jun 2019 14:55
Hello. Our project will look similar, and this week the structural frame contractor will start work—4 weeks earlier than expected. The earthworks are included in the shell construction price. I can share these details if you want. We will have strip foundations all around and a 14cm xps insulation layer on the slab.
Regards, relio
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Bauvorhaben20
4 Jun 2019 11:52
vx220 schrieb:

Hello. Our project will look similar, and the structural carpenter is starting work this week, 4 weeks earlier than expected. Excavation work is included in the rough construction price.
I can gladly share details if you want. We will have strip footings all around. And a 14cm xps insulation on the slab.
Best regards, relio

Sure, how much do you need to backfill?
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Jenpa
4 Jun 2019 14:40
Guys, it doesn’t make sense to ask about the volume of soil without knowing the soil type or the elevation difference. What good is the answer “500m³ (650 cubic yards)” if you first need to remove material because it’s not load-bearing?
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Bauvorhaben20
4 Jun 2019 21:25
I still find it helpful to have some points of reference.