The Home Builder Association warns that flood damage often hides in wiring, structure and trapped moisture. Do not switch on electrics that were under water until a qualified electrician has checked them. Have engineers inspect structural cracks, sloping floors or doors that no longer close, especially after long flooding. Dry walls, floors and timber fully before painting or sealing, since covering damp materials lets hidden problems get worse. Follow the sequence Safety, Inspect, Dry, Repair.