ᐅ Comparison of Soil Investigation Quotes

Good evening everyone,

We are planning to purchase a plot of land in the HS district. It is not yet decided whether we will build with or without a basement.

I have requested soil investigation quotes from two companies. One offer is clearly more detailed and also more expensive. As a layperson, the main points seem to be:

Offer A:
- Two dynamic core drillings with a diameter of 36/50 mm (1.4/2 inches), including identification and description of the soil by the operator, drilling depths up to 5.0 m (16.4 ft)
- Ten soil sample collections, geological assessment of the bore material as well as organoleptically detectable contamination
- One dynamic probing of 5 m (16.4 ft) according to DIN EN ISO 22476-2
- Evaluation including recording of bore points, allowable soil bearing capacity, design groundwater level, foundation recommendation, waterproofing, bedding modulus

Offer B is much shorter in description but also less expensive:
- Site investigation including travel, two small dynamic drillings, tabular evaluation, and topographic site survey.
- Additionally, "light dynamic probing" can be booked for 100 euros each.
There is no information on depths or soil samples.

Could anyone help evaluate these two offers?

Thanks and best regards

I’ll respond by noting that our discussion about the geotechnical report was several months ago, and I am an informed layperson myself (I have read and compared six offers from different surveyors):

Which geologist or geotechnical engineer you hire mainly depends on the specific site conditions. There may already be an older report available?!

If you have farmland, I wonder how useful soil samples would be. If your plot is on former industrial land, soil sampling should definitely be done. Ultimately, soil analyses are used to detect contaminants. In my case, this was always an additional cost item.

The diameter of the borehole probably doesn’t matter. Depths can be specified; it should not be less than 590 cm (or was it 690 cm (232 or 272 inches)?)

Ultimately, as a client, you want recommendations for foundation design and information on the groundwater level.

Two rotary core borings and one dynamic probing are usually the “standard scope” for a single-family house.

If anyone knows better than I do, please feel free to correct me.

By the way, I paid about 650 gross for an offer in the mid-range price bracket.

Hello,

CharlieBrown schrieb:

We intend to buy a plot of land in the HS district.
It is still undecided whether to build with or without a basement.

That will probably come down to the budget; however, since more work is usually done on weekends in HS than on weekdays, it might also be a matter of "who is who."

CharlieBrown schrieb:

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

Offer A:
- 2 percussion core drillings, diameter 36/50 mm (1.4/2 inches), including identification and description of the soil by the operator, depths up to 5.0 m (16.4 ft)
- 10 soil samples taken, description of the drill core from a geological perspective as well as organoleptic detectable contamination
- 1 percussion sounding 5 m (16.4 ft) according to DIN EN ISO 22476-2
- Evaluation including recording of bore points, allowable soil bearing capacity, design groundwater level, foundation recommendation, waterproofing, bedding modulus

Offer B is much shorter in text but also cheaper:
- Geotechnical investigation including travel, two small percussion drillings, tabular evaluation, and topographical survey of the site.
- Additionally, "light percussion sounding" can be booked for 100 euros each
No information is given about depths or soil samples.

When commissioning a soil survey, you should not focus on saving the last euro; going cheap will usually end up costing a lot more in the end. In this sensitive area especially, since the foundation will be based on the survey results.

By the way, I want to disagree with the previous poster here; even under agricultural land, for example, a water vein can run. Building without a soil survey is a pretty foolish and expensive risk.

For me, offer B is ruled out from the start; since percussion sounding (necessary to determine soil density) is offered as an extra service, it is probably extremely cheap in quality.

Furthermore, as with later construction contracts: what is not included is considered not purchased. A decent soil survey here in the Rhineland usually costs around €800-900 plus VAT, depending on whether infiltration testing is included; always very well and wisely invested money!

Regards, Bauexperte

Hello everyone,

thank you for your comments.

I have one more question: Is it generally sufficient to have 2 rotary core drillings and 1 dynamic probing for consultation?
I often read about 4 drillings at the planned building corners...

The plot is a former cemetery extension area. I don’t know exactly how old the cemetery is, but it has been there for several decades.
Industrial contamination is probably ruled out, but information about the subsoil is important enough anyway.

Thanks and best regards

Hello,

CharlieBrown schrieb:

My question still is: Is using 2 dynamic core drillings and 1 dynamic probing generally considered sufficient for consultation?

2 + 1 has become largely accepted as "standard," as ypg already mentioned.

Regards, Bauexperte

CharlieBrown schrieb:


The plot of land is the former expansion area of a cemetery.

As far as I know, cemetery soil is contaminated and contains many pollutants...