Abstract: Methods and apparatus for remediating buildings damaged by floodwaters. The methods include removing floodwater-damaged wall cladding to expose underlying structure. Applying under pressure a chemical composition to remove malodor and that penetrates into the underlying structure. Then, allowing a powdery surface coating to form on surfaces of the underlying structure. Useful apparatus includes a container configured to contain a liquid phase of a chemical composition and a pressurized gas canister associated with the container for supplying gas under pressure to a fluid conduit extending from an inlet of the container to an outlet of the container. The apparatus can include a venturi in a flowpath of the fluid conduit which suctions a chemical composition in the container into the fluid conduit for expulsion from the outlet of the container and into a high pressure spray delivery hose.