ᐅ Soil report: who is best qualified to assess this?

Hello everyone,

My partner and I plan to build a house this year in a new development area. The plot is reserved, and the seller had an environmental and geotechnical survey conducted for the entire area. We also have access to this report.

Regarding the house, we are currently obtaining two quotes:
- a general contractor based in a neighboring town who comes recommended
- an architect based locally who is also recommended

Now I am wondering whether both parties are able to interpret the survey results correctly in terms of any potential additional costs and if they would be responsible should such extra costs arise. Or would it perhaps make sense to already approach a civil engineer specializing in earthworks with the survey results and request a quote?

Would it also be advisable to commission a separate soil report specifically for our plot? Or is the current survey sufficient? In the survey, 12 boreholes were carried out over an area of 2,628 sqm (of which 405 sqm (4,360 sq ft) pertains to our plot).

Many thanks
Teufelchen

Does the expert report include a foundation recommendation? If so, the general contractor and architect will plan accordingly, and they must do so if they were aware of the report at the time of planning.

Good morning,

Teufelchen1985 schrieb:

My partner and I plan to build a house this year in a new development area. The plot is reserved, and the seller had an environmental and geotechnical survey conducted for the entire site. We have received this report as well.

Where in NRW is the plot located?

Teufelchen1985 schrieb:

Regarding the house, we are currently obtaining two offers:
- a general contractor based in a neighboring town who comes recommended
- an architect based locally who also comes recommended

Now my question is whether both parties can properly interpret the survey results regarding any potential additional costs and if they would also be responsible should such costs arise.

This seller’s report relates only to the construction of the planned roads within the development; individual plots may correspond to the findings, but they do not have to. Therefore, the liability of both parties regarding a single plot is practically zero—unless the individual measurement points reveal indications of serious ground issues.

Teufelchen1985 schrieb:

Would it possibly make sense to commission a separate soil survey for our plot? Or is this survey sufficient? The survey included 12 boreholes over an area of 2,628 sqm (of which 405 sqm (4,360 sq ft) belong to our plot).

I would never build without a site-specific geotechnical survey; the liability in the worst case can be severe. Even if the 12 measurement points seem unproblematic at first glance, there "could" be a need for soil replacement on your plot, a water vein running under the build area, or other issues.

This also answers the question about hiring a civil engineer.

Kind regards

Hello Teufelchen,
It was also explained to me this way (which I find convincing) that the builder can always refer to the missing soil survey in case of later damages, which is the responsibility of the client. Therefore, they do not have to be liable for such damages. If a soil survey is available, where three boreholes are made exactly where your foundation slab is located, the builder can and must anticipate this and be liable later.

Hello, we had a geotechnical survey done for the plot. Two boreholes of 8 meters (26 feet) and two boreholes of 4 meters (13 feet), each in the corners of the planned house. Based on the foundation recommendations and the soil layers described in the report, we were given a fixed-price surcharge for the groundwork included in the package. This surcharge is based on the offer from the civil engineer working for the general contractor and amounts to almost five figures. I think 12 boreholes is a bit excessive. What the general contractor or civil engineer keeps as a clause is the unforeseen occurrence of hitting bedrock (which, according to our geotechnical report, is not expected) and is therefore more of a formal clause.

What we see as an advantage of having a geotechnical survey done specifically for our plot (there could have been a general one for the area as well) is:
- We can negotiate a fixed surcharge upfront which should not be exceeded under normal circumstances.
- If the building settles due to an incorrect structural calculation or something similar, we can clearly hold the general contractor responsible for planning errors, since we provided them with a geotechnical survey and they did not have to rely on assumptions.