ᐅ Clayey soil. Is soil replacement recommended for the foundation?

Our building site has cohesive soil (silt, clay content, poorly water-permeable). Such cohesive soil is suitable for house construction but tends to settle over time. In addition to drainage, is soil replacement advisable? And at what depth?

Or is a 30cm (12 inches) layer of gravel that breaks capillary action below the foundation slab sufficient?

You can find this information in your soil report. It details what type of soil is present at which depth.

It is similar for us; at least 80 cm (31.5 inches) of gravel is laid (currently in progress). The geotechnical report should include a foundation recommendation.

The foundation recommendation calls for a structurally reinforced concrete slab and a capillary-breaking layer of at least 30 cm (12 inches) beneath the slab. Nothing more.

That seems a bit minimal to me. I would rather invest a few thousand euros and possibly carry out soil replacement. But does that make sense?

When the geologists say it works like this, then it works like this... or do you have too much money? I’ll give you my account....