This is what people do in Oakland to add more space to older houses.https://twitter.com/TommSciortino/status/1148759329756987394 …
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Lifting minimizes "new construction" which is much more restrictive and expensive than rehabbing existing. Plus lot coverage, setbacks, etc are probably different (worse) now than when the house was built.
Quite possibly the lot is nonconforming and you can't build any new houses on it at all, but the FAR and height limits aren't maxed out.
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