Can the rubber flooring be biodegraded? How long will this take?

Depending on the type of rubber used in the flooring, it could take as many as to 80 years to biodegrade... You might consider doing some reasearch on the type of flooring and find out whether it was made with biodegradable materials to better answer your question...
i am not sure what you mean by rubber flooring. i know PVC (polyvinilchloride) floors, which are not much environmental friendly, or linoleum aka marmoleum, which is stone dust, vegetable oil and resins and cork dust. looks pretty much the same, only is environment friendly, chlorine free, from renewable resources, biodegradable. it was used for floorings before PVC was known - it is extremely durable, and now it is getting more popular (more modern design) as PVC is tried to be phased out.