Construction of the old building's foundation slab - 1964 - Section available

Hello everyone,

my wife and I have bought a house from 1964. We are still unsure whether to demolish and build new or to do a core renovation. Our biggest concern regarding the renovation is the floor slab. As you can see, it is quite thin concrete between the strip foundations. However, the cross-section also shows that the floor slab in the front area (the house is on a slope, front area = garden side or living room) is constructed differently. Can an expert among you say what this drawing says about the structure? We want to avoid losing room height by using high insulation on the floor slab and, even more important, we want to avoid adjustments to stairs, etc. Looking forward to your feedback!

Thanks and regards
Alex

Our biggest concern regarding the renovation is the base slab. As you can see, it is quite thin concrete between the strip foundations.

No. We see, but it is not too thin.

Can an expert among you say what this drawing says about the structure?

I prefer the term specialist. And yes, for that you really should not have left out the floor plans.