Hi! We have become interested in a brick house from 1966. Parts of the house are below ground level, and the drainage was redone about 20 years ago. The foundation is a slab of Y-tong with a wooden joist floor above it 
This makes me a bit worried.. Why was it built like that? Isn't there a big risk of moisture in the joists? Terrified :-/
Also, I don't really know much about brick houses at all.. I've also heard that there might be radon in old Y-tong - does anyone know anything about that? Is it difficult to replace windows in a brick house?
I would be very grateful if you could help me and share your thoughts, tips, and advice!
/Lisa
This makes me a bit worried.. Why was it built like that? Isn't there a big risk of moisture in the joists? Terrified :-/Also, I don't really know much about brick houses at all.. I've also heard that there might be radon in old Y-tong - does anyone know anything about that? Is it difficult to replace windows in a brick house?
I would be very grateful if you could help me and share your thoughts, tips, and advice!
/Lisa
Replacing windows is not particularly difficult with the right tools. It takes a little longer since you have to drill into brick instead of wood, but that's all.
In the 50s to 70s, many strange foundations were built that today people just shake their heads at. I think that one of those is exactly what you are describing. However, I think you should consider this way: What problems have arisen until today? Those problems will likely worsen over the years. If no problems have arisen, they probably won't in the future either. However, many factors play a role, not least the composition of the soil and its ability to drain water. Similar foundations can behave differently depending on where they are geographically located.
In the 50s to 70s, many strange foundations were built that today people just shake their heads at. I think that one of those is exactly what you are describing. However, I think you should consider this way: What problems have arisen until today? Those problems will likely worsen over the years. If no problems have arisen, they probably won't in the future either. However, many factors play a role, not least the composition of the soil and its ability to drain water. Similar foundations can behave differently depending on where they are geographically located.