Soil made of loess and trench slabs. What are the effects on house construction?

Hello! We have a plot in mind, which consists of loess and terrace slabs. Does anyone know what that means and what implications it could have for house construction?
Best regards, Melanie

Hello Melanie,

Loess is a silt that is cemented by a certain lime content.
Silt in turn is a water- and wind-transported (erosion) mixture of dust-fine sands with no or only a small proportion of raw clay.
Through the weathering of loess, where the lime content is leached out, loess loam is formed.

Such soils become quite slippery when it rains.

By the term terrace slabs I understand a slab covering for the terrace. Or perhaps you mean "Tarras"?

Tarras is a green silt clay (mixture of dust-fine sands and clay) from the Upper Tertiary.

At what depth is the groundwater level?

All in all, I hope for you that this property is not on a slope and please, rubber boots with a coarse sole are recommended here.

Hello Danton! The property is not on a slope, it is a large field that is planned to be developed soon. The development plan is currently being processed by the city. In the explanatory text of the development plan, it says terrace slabs, but maybe it is also a typo, I will investigate that again. We also do not know the groundwater level yet. Could there be construction difficulties with the soil, apart from the groundwater level and the fact that it becomes muddy when it rains? Melanie

Hello Melanie,

great structural difficulties are rather not to be expected, as far as a remote diagnosis allows.
However, if the new house is supposed to have a basement, I would pay increased attention to the basement's watertightness, since this soil retains moisture longer than coarser soils like sands, for example.

For the plants in the garden, it might actually be more advantageous, provided that there is also a proper layer of topsoil above it. For fields or arable land, this is usually the case.

If you have further questions, just get in touch.

Property Hello Thomas! You answered me recently on the subject of property with loess soil. I have now found out that the soil is loess and the groundwater level is at 73/75. Can you tell me what that means?

Best regards

Melanie

Hello Melanie,

I took the liberty of copying your private message here, as this might also interest other users.

I have already explained what loess soil is. If the groundwater level is given as 73/75, it probably means that the groundwater stands about 3/4 meters below the ground surface. This can easily be found out with a spade.

This means that if you want to build a house with a basement here, water pumping will definitely be necessary during the first construction phase (up to basement ceiling) and the basement should be constructed as a "white tank" (waterproof reinforced concrete with appropriate detailing). If a house without a basement is planned, excavation of the foundation trenches should ideally begin directly after a certain dry period. In both cases, careful sealing against rising damp is also necessary.

May I ask in which region of Germany you want to build?

In NRW in Mülheim an der Ruhr