ᐅ Material of the base layer for the ground slab

Hello,

IronBen schrieb:

For the construction of the foundation slab, a hole is excavated into which sand or gravel is placed and compacted. Then the foundation slab is laid on top. My question is not about the soil itself, but about what should be compacted in that hole. Which is better: sand or capillary-breaking gravel? (The soil itself is the same in both cases...)

This is something the forum or its members cannot answer.

If you plan to build a new house, do yourself a favor and have a soil investigation carried out. The geotechnical engineer will provide you with detailed foundation recommendations specifying the most suitable type of foundation. Anything else, in my opinion, is irresponsible or like playing Russian roulette!

Best regards, Bauexperte

Thank you for the answers – now I’ll take a step back to clarify the main issue:

In the construction descriptions from developers, it always says, "The foundation slab is built on a compacted base layer of XYZ." Sometimes it mentions sand, sometimes gravel, but none of the descriptions specify that this depends on the soil conditions. I’m trying to use this point in the construction description to determine which one is "better" – in other areas (like the price per square meter for tiles), the comparison is much easier for me as a layperson.

However, if you say that what is required under the foundation slab depends on the soil, then it is not possible to tell from the construction descriptions alone “which of the two descriptions is better.”

Hello,

IronBen schrieb:

Thanks for the answers – I’ll take a step back to clarify the main point:

If you want reliable answers, it’s not a bad idea to start from the beginning.

IronBen schrieb:

In builders’ specifications, it always says, “The foundation slab is built on a compacted base layer made of XYZ.” Sometimes sand, sometimes gravel, but nowhere in the specifications does it say that this depends on the soil condition. I’m just trying to determine which specification is “better” based on this point – at other points (like the price per square meter for tiles), the comparison is, of course, much easier for me as a layperson.

First of all, you need to distinguish between a developer and a general contractor. Developers offer you land and house as a package, usually payable in a maximum of seven installments. General contractors build on your land (which you arrange yourself) and invoice in 10 up to even 20 installments (the latter, in my view, is unreasonable; you might as well stay at the bank).

In the vast majority of building specifications I know, it is either stated that the soil survey is included in the price or must be provided by the client. Whether it says sand or gravel is initially just an indication of what the provider’s standard includes. If the survey shows that you cannot build on sand or gravel, additional costs arise for the client; so-called foundation-related extra costs. Important for all specifications: what is not written in the specification is not owed (purchased).

IronBen schrieb:

But if you say it depends on the soil what foundation layer is needed beneath the slab, then based on the specifications alone you can’t tell “which of the two specs is better.”

See above.

Regards, Bauexperte