ᐅ Soil report results for a single-family house of approximately 240 sqm with a concrete slab foundation

Created on: 9 Oct 2021 18:41
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Saldier
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Saldier
9 Oct 2021 18:41
Hello dear forum members,
we are planning to build a single-family house of about 240 sqm (2,583 sq ft) with a concrete slab foundation.
We had a soil survey carried out for this, and the following results were received:

Geology of the foundation area
Periglacial-fluviatile deposits, sandy to sandy-silty, over Late Weichselian ground moraine

Soil layers
Layer 1: 0.00–0.30 m (0.0–1.0 ft) topsoil and fill material OU, SW
Layer 2: 0.30–2.50 m (1.0–8.2 ft) fine sand to medium sand SW
Layer 3: 2.50–4.20 m (8.2–13.8 ft) medium sand, alternating clayey-silty
SW, ST*
For layer 2 at < 0.5 m (1.6 ft): For layer 2 at 0.8 m (2.6 ft):
Ks = 36 MN/m³ (meganewtons per cubic meter) at b = 1.0 m (3.3 ft)
Kg = 72 MN/m³ at b < 0.5 m (1.6 ft)
a = 300 kN/m² (kilonewtons per square meter)
a = 240 kN/m²

Soil classes:
Layer 1: 1–3, Layer 2: 3, Layer 3: 3–4

Groundwater situation
Groundwater at 3.8–4.0 m (12.5–13.1 ft), temporarily no expected rising seepage water in the foundation area

Foundation / Earthworks
Load-bearing slab without frost protection footings or strip footings, height = 0.8 m (2.6 ft),
Base layer 20–25 cm (7.9–9.8 inches) (DPr > 0.98)

Surface water infiltration
Vertical structure with filter zone from 0.4 m (1.3 ft) in layer 2

Could someone please tell me whether this is a good or bad result?
Should I expect increased costs for the concrete slab due to poor soil conditions, or am I even lucky and it is the opposite?
I would very much appreciate your experience and opinion.

Best regards,
Saldier
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guckuck2
9 Oct 2021 19:17
Everything is completely normal. No additional effort is noticeable.
K1300S10 Oct 2021 07:29
Saldier schrieb:

Can someone now tell me if this is a good or bad result?
I think it really doesn’t get much better than this.
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Pinkiponk
10 Oct 2021 10:11
Saldier schrieb:

Do I now need to expect higher costs for the foundation slab due to the poor soil, or am I actually lucky and it turns out to be the opposite?

My previous commenters have already confirmed that you don’t need to worry about this anymore based on the soil survey. Great, I’m happy for you.
My information is therefore mainly for those reading here who might have a similar question. It can also be the other way around—that due to the soil survey, the foundation slab becomes cheaper (in our case by about 8,500 euros) while the earthworks become more extensive (we don’t have quotes for those yet).