Can a strata insurance claim by the OC get rejected if an owner previously completed major renovation works without OC approval nor a special by-law?
It might if it changed the risk in some way.
But every strata insurance policy I’ve seen covers “Lot owners’ fixtures and improvements“. An OC might not be aware of what they even are.
And to note that in many types of strata around Australia, the lot owner owns and maintains the building and so does not actually need strata approval or new by-laws/rules for internal renovations. Yet the insurance company and policy is the same around the Australia.