Feasibility of building a sports hut yourself on a strip foundation

Hello everyone, I am planning to build a sports room on my property and have a few questions regarding feasibility. The ground was excavated to one meter and filled and compacted with recycling material. Now I am considering constructing a strip foundation with formwork blocks (EHL formwork block, 50 x 17.5 x 25 cm) and building a small house on it with Ytong blocks (aerated concrete block Planblock, 60 x 15 x 19.9 cm, compressive strength: class 2). The dimensions should be 4m x 4.5m. Should this work and will the walls be stable enough? Thanks for your help and best regards Adrian

I do not recommend amateur work for such projects.

Walls should be stable enough?

A structural engineer will tell you that.... Regarding structural experiments, you can look in the press what sometimes happens in Turkey, and how many deaths are due to improvised constructions (load-bearing walls removed from supermarkets, etc.).

There still has to be a roof on the wall, etc. This will not be a small treehouse but a lounge area (which, if in doubt, even requires a permit).

Unlike the others, I am of the opinion that you do not need a structural engineer for this. Such huts have been built for centuries. If you know a bricklayer, ask him or switch to timber construction.