Comparison of construction site investigation offers

Good evening everyone,

we intend to buy a plot of land in the HS district. Whether we build with or without a basement has not yet been decided.

I have now asked two companies for an offer for a soil survey. One offer is clearly more detailed textually and also more expensive. The main points seem to me as a layperson to be:

Offer A:
- 2 pieces of percussion core drilling diameter 36/50 mm, including description and assessment of the soil by the equipment operator, depths up to 5.0 m
- 10 pieces of soil sampling, assessment of the drill core from a geological perspective as well as on organoleptically recognizable contamination
- 1 piece of percussion sounding 5 m according to DIN EN ISO 22476-2
- Evaluation including recording of boreholes, permissible soil bearing pressure, design water level, foundation recommendation, sealing, bedding modulus

Offer B is much shorter in text, but also cheaper:
- Soil investigation including travel, two small percussion drillings, tabular evaluation and topographic site survey.
- Additionally, "Light percussion sounding" can be booked for 100 euros each.
Nothing is said about depths or soil samples.

Can any of you evaluate these two offers?

Thanks and regards

I will respond with the note that our topic of the geotechnical report dates back months ago and I am a self-taught layman (I read through and compared 6 offers from experts): Which geologist you hire essentially depends on the circumstances. Perhaps there is already an older report?! If you have farmland, I wonder what soil samples would be good for. If you have a property on former industrial land, soil samples should be taken. Ultimately, you want to determine pollutants with soil analyses. In my case, this was always an additional item. The diameter of the drilling should probably not matter. Depths can be specified, it should not be under 590cm (or was it 690?). Ultimately, as the builder, you want a foundation recommendation and to know the groundwater level. Two percussion core drillings and one percussion sounding is probably the "standard order" for a single-family house. Anyone who knows better than me, feel free to correct me. By the way, I paid about 650 gross for an offer in the mid-range.

Hello,

we intend to buy a plot of land in the HS district.
Whether we build with or without a basement is not yet decided.

That will ultimately be a question of the budget; but since more work is usually done in HS on weekends than during the week, it might also be a question of "who is who"

I have now asked two companies for an offer for a soil survey.
One offer is clearly more extensive in text and also more expensive.
The main points seem to me as a layman to be:

Offer A:
- 2 percussion core borings diameter 36/50 mm, including identification and description of the soil by the operator, depths up to 5.0 m
- 10 soil samples taken, identification of the borehole material from a geological perspective as well as for organoleptically recognizable contamination
- 1 percussion sounding 5 m according to DIN EN ISO 22476-2
- Evaluation recording of boreholes, allowable soil pressure, design water level, foundation recommendation, waterproofing, bedding modulus

Offer B is much shorter in text but also cheaper:
- Soil investigation including travel, two small percussion borings, tabular evaluation, and topographical site survey.
- Additionally, "light percussion sounding" can be booked for 100 euros each.
Nothing is said about depths or soil samples.

When commissioning a soil survey, you should not look at the last euro; cheap always ends up being quite expensive anyway. Especially in this sensitive area, because the foundation is based on the results of the survey.

By the way, I also want to disagree with my predecessor here; even below a field, for example, a water vein can run. Building a house without a soil survey is quite a stupid and expensive matter.

For me, offer B is excluded per se; since the percussion sounding (required to determine the density of the deposits) is offered as an additional service, it is probably dirt cheap.

Besides, the same applies here as with the later contract: what is not included is considered not purchased. A reasonable soil survey commissioned here in the Rhineland usually costs € 800-900 plus VAT, depending on whether with or without infiltration; always very good and wisely invested money!

Rhenish greetings

Hello everyone,

thank you for your comments.

My question still is: Is it generally sufficient to have 2 ramming core drillings and 1 ramming sounding?
You often also read about 4 drillings at the planned building corners...

The property is the former extension area of a cemetery. I don't know exactly how old the cemetery is, but it has been around for several decades.
Industrial legacies are probably excluded, but the information about the soil is important enough as it is.

Thanks and regards

Hello,

My question still is: Is one generally sufficiently advised with 2 percussive core drillings and 1 percussive sounding?

2 + 1 has – as ypg has already written – become widely established as "normal."

Rhenish greetings

The property is the former expansion site of a cemetery.

Cemetery grounds are, to my knowledge, contaminated and full of pollutants...