Hello everyone,
we are interested in a building plot in a residential development area.
The development plan includes a brief description of the "soil investigation," which raises some concerns for me.
Does anyone here have some knowledge about soil conditions/soil quality so that I can get an initial idea whether this area is "generally okay," or if I should already expect significant extra costs due to poor soil conditions?
I fully understand that an individual geotechnical report is necessary for a precise assessment. But maybe I can get some first indications – thanks in advance!
Here is the description from the development plan:
The subsurface consists in the upper layers of heavily cohesive silt and clay soils, which transition downward into stony weathered soils of the Keuper formation. In the eastern area, obstacles from emerging rocky soils of the Keuper have also been identified. The topsoil thickness is about 0.40m (16 inches). These soils were found between 1.0m and 3.0m (3.3 and 9.8 feet) below ground level and represent a moderate and settlement-prone subsoil. From northeast to southwest, the clay soils become increasingly thicker. The stone content in the soils increases with depth (stony weathered clay of the Keuper). Slight bedding was also occasionally observed within the soils, indicating emerging rocky soils in the subsoil.
Overall, only moderate bearing capacities are expected on the street planum with highly frost-sensitive soils. Soil replacement measures are required.
Especially the last paragraph catches my attention. Is this a normal situation, or should I already consider this as "problematic ground"?
Also, not every plot allows for a basement. In some cases, the topsoil layer is too thin, so that excavation for a basement is not sufficient.
I would really appreciate your opinions!!
Many thanks,
Robin
we are interested in a building plot in a residential development area.
The development plan includes a brief description of the "soil investigation," which raises some concerns for me.
Does anyone here have some knowledge about soil conditions/soil quality so that I can get an initial idea whether this area is "generally okay," or if I should already expect significant extra costs due to poor soil conditions?
I fully understand that an individual geotechnical report is necessary for a precise assessment. But maybe I can get some first indications – thanks in advance!
Here is the description from the development plan:
The subsurface consists in the upper layers of heavily cohesive silt and clay soils, which transition downward into stony weathered soils of the Keuper formation. In the eastern area, obstacles from emerging rocky soils of the Keuper have also been identified. The topsoil thickness is about 0.40m (16 inches). These soils were found between 1.0m and 3.0m (3.3 and 9.8 feet) below ground level and represent a moderate and settlement-prone subsoil. From northeast to southwest, the clay soils become increasingly thicker. The stone content in the soils increases with depth (stony weathered clay of the Keuper). Slight bedding was also occasionally observed within the soils, indicating emerging rocky soils in the subsoil.
Overall, only moderate bearing capacities are expected on the street planum with highly frost-sensitive soils. Soil replacement measures are required.
Especially the last paragraph catches my attention. Is this a normal situation, or should I already consider this as "problematic ground"?
Also, not every plot allows for a basement. In some cases, the topsoil layer is too thin, so that excavation for a basement is not sufficient.
I would really appreciate your opinions!!
Many thanks,
Robin
S
Stefan89020 Jun 2019 21:54If the description applies to a larger development area, it does not necessarily have to be the same for every plot. However, it is advisable to expect that soil replacement will be necessary and to budget accordingly.
Here it is:
This pattern naturally applies to the entire construction area.
Rob11 schrieb:
From northeast to southwest, the clay soils become increasingly thicker
Rob11 schrieb:
Soil replacement measures are necessary.
This pattern naturally applies to the entire construction area.
M
Mottenhausen21 Jun 2019 09:47Frost sensitivity is not an issue; every house must have a frost-free foundation.
If I understand and interpret this correctly, there is only one problem: the soil is difficult to compact and may settle. Therefore, I believe that for the geotechnical reports of homeowners without a basement request, a pile foundation will partly be recommended. Alternatively, building with a basement at living space height means excavating the "critical" 3 meters (about 10 feet) mentioned in the report anyway, and the foundation should no longer be a problem.
If I understand and interpret this correctly, there is only one problem: the soil is difficult to compact and may settle. Therefore, I believe that for the geotechnical reports of homeowners without a basement request, a pile foundation will partly be recommended. Alternatively, building with a basement at living space height means excavating the "critical" 3 meters (about 10 feet) mentioned in the report anyway, and the foundation should no longer be a problem.
Thank you in advance.
What would a pile foundation involve?
I want to estimate whether this would mean moderate additional costs (up to about 10,000) or significantly more (up to about 30,000–50,000) compared to a "standard soil" foundation.
Of course, this can’t be answered generally, but maybe someone has had similar conditions.
Thank you
What would a pile foundation involve?
I want to estimate whether this would mean moderate additional costs (up to about 10,000) or significantly more (up to about 30,000–50,000) compared to a "standard soil" foundation.
Of course, this can’t be answered generally, but maybe someone has had similar conditions.
Thank you
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