In the absence of a specific by law, I don’t see why OC approval would be needed. Therefore I don’t see why you need to get ‘retrospective’ approval and would need to raise it at the AGM.
What sort of floor was the floating floor replacing? If the replacement floor was something fixed to the floor boards (which are common property) eg ceramic tiles I could see why you needed approval. Being a floating floor I don’t think it would form part of common property and would not need approval.
A few years ago I replaced the carpet in my unit I didn’t tell anyone and sought no approval.