Soil survey report for prefabricated house in timber frame construction

Hello everyone,

since I am unfortunately not an expert regarding house construction and unfortunately do not get any wiser in many cases through the search function in forums, I have decided (in addition to my post about the foundation slab) to open a post about the offers I have received so far regarding my planned soil survey.

Briefly to the background, we are planning a prefabricated house in timber frame construction without a basement with a floor area of just under 90 sqm. Since we are currently trying to get a better overview of the incidental building costs, we want to have a soil survey carried out to find out what our building ground looks like and what costs will come up in relation to excavation etc. for the foundation slab.
The planned house is to be built on a plot of land on which a house already stands, built in the 1950s. Unfortunately, there are no documents about the building ground.

Now we have received various offers for soil surveys with various prices (€750 - €1,300 net) and services (from 2 percussion core drillings up to 2 small percussion drillings + 2 heavy percussion drillings).
The question now is whether the cheapest (€750 net) already includes sufficient services.

Baugrund- und Gründungsgutachten
Preparation of a soil and foundation report according to DIN 4020 based on a residential building with a floor area of up to approx. 140 sqm on the basis of the field investigations:
Evaluation and presentation of the results of the field investigations, creation of a soil profile showing the expected foundation bottom, soil assessment with indication of characteristic soil parameters and soil classes, notes on compaction ability, reusability and infiltration ability of the in-situ soils, notes on the seismic zone, presentation of foundation options and proposal for the foundation including permissible soil pressures, notes on the groundwater or groundwater table conditions and on the dewatering of the excavation pit, indication of the necessary structural waterproofing measures, notes on construction execution. Preparation and delivery of three copies of the report.

Felderkundung - Rammkernsondierungen
Mobilization and transport to/from site of personnel and equipment, provision of equipment for the duration of the investigations, including travel costs. Drilling of two percussion core drillings to investigate the underground layering and soil bearing capacity, drilling depth approx. 4 m to 6 m in drillable soil, core tube diameter up to approx. 60 mm, depth-appropriate laying out of the drilling cores for geotechnical and organoleptic evaluation. Surveying of the drilling start points according to position and elevation referencing a reference point, e.g. manhole cover, if available.

If soil needs to be removed, you still need a LAGA examination.

The LAGA inspection is not included in the initial price in any offer, but is offered optionally everywhere. I only know if soil needs to be removed when I have the soil report, right? Doesn't that mean that it can still be commissioned afterwards if necessary?

So we had offers ranging from 650 to 2500 euros with apparently more or less the same content. We also didn't know how to compare them and in the end decided based on budget, sympathy, and a bit of recommendation.

By the way, we still needed a clearance for unexploded ordnance from the police or an unexploded ordnance disposal service.

Hello, I have the following offer:
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- 2 small percussion drillings
- 4 dynamic probing tests
The decision whether to use the light or heavy dynamic probing test depends on the local soil conditions.
If a 3rd or 4th drilling becomes necessary, the work will be carried out additionally at no extra cost.

Cost: 1,275.00 EUR plus VAT.

Details:
includes the following points:
- Evaluation of the exploration results
- Description of the soil from a geological
and soil mechanical perspective;
- Soil classification according to DIN 18 300;
- Description of the groundwater conditions
- Presentation of the explorations in profile sections
- Suggestions for economical and technically
optimal foundation types
- Indication of the permissible soil pressure
- Instructions for earthworks, excavation design,
and dewatering
- Indication of approximate settlements and
differential settlements
Including soil investigation, depending on the situation:
2 - 4 small percussion drillings, depth approx. 3 m
4 dynamic probing tests, depth approx. 3 m
or down to bedrock
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Is this a fair offer or should we obtain further offers?

I would always get several quotes anyway. We paid about 750 with us.