@okh : How much do you estimate the thickness of ground that a tree needs ?
I have always been told that a tree, there are as many in the air as in the ground ...
The subject about atrium is big... [B-)] [:)]

We may just be offering more advice than the artist ever asked for here. But, yes, my understanding is that rule-of-thumb: the root system of a wild tree will generally match the branches/twigs to sustain the foliage. But having chopped down a few, I dare say it really is not universal, and the root system can still be contained in a smaller volume soil if water nourishment is sufficient. Just look at ficus and other trees in flower-pots.

Either way, even on the ground floor, Miker777 will need to contain and control the root system. Little water will seep through under the house, and the roots must be prevented from interfering with the foundation, sewerage etc. not to mention the pool in the next room. Even so, it is true, that an elevated atrium would need a quite large "flower-pot" to sustain a ceiling height tree. But I think not to an extent where it would be impossible. ok


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