Evaluation of Building Ground Survey

Hello everyone,

Happy New Year to all.

After I was active for the first time 5 years ago and our floor plan was rightly heavily criticized there, we are now starting a second attempt.

We already have a plot of land where we have now had the expert report created. Basically, it reads to me that we have good soil for building a house. What I find strange, however, is that drilling stopped after a maximum of 2.8 meters.

The reason given on site was that layer 2 or 3 slips in such a way that they have problems getting the probe back out.

We commissioned the drillings for a house with a basement, so now we only know the soil quality of the soil that will be removed, but not of the soil on which the house will later stand. After consulting with the geologist, the statement was that this is normal with such soil conditions. Based on experience, the further layers do not change anymore or are then firmer. I do not want to question anyone’s expertise or experience. But has anyone already had similar experiences here? Or is there someone who is familiar with the matter?

Regards
Slipschneck

No drilling progress would mean that rock or stone prevents further drilling. Did the geologist know that you want to build with a basement?

With the sandy material, I could imagine that the probe can no longer be retrieved "non-destructively" because the material sliding down above compacts too much. Similar to quicksand or the like.

One could make a scraping with an excavator bucket and then carry out another drilling on its sole.
The stop at 1.9m in the middle of the construction area would somehow be a "sign" for me to become alert!

Do you already have a pre-installed handover shaft/channel connection? If yes, how deep is it? What height difference is planned later for the wastewater disposal?

Yes, the order was placed in writing. On his order form, we also marked single-family house with basement accordingly. The planned construction project is also stated in the report itself.

In the middle of the building site, there is currently still a barn and the ground is asphalted. Therefore, it is rather difficult to just dig with an excavator. There are currently no shafts either.

I just spoke with the neighbors. For them, the ground looked just like in the report. However, that means nothing for our property.

We will demolish the barn and the asphalt in February. Then I can have the excavator dig deeper.

Good morning everyone,

I have now received the following in writing from the geologist.

"The drillings were not stopped at 1.9-2.9 m, but there was no further drilling progress. This is an indication that the gravel content in the terrace sands and the degree of consolidation in the foundation area are very high. Excavability is, of course, given up to the basement floor. Similar conditions exist, for example, in Munich, where we often can drill less than 1 m deep with the RKS."

Maybe this helps some of you if you ever receive such a report yourself.

Regards
Schneckham