What causes soft spots in linoleum floors?

Soft spots in linoleum floors can be  caused by several factors, all of which are due to moisture issues. Mold and mildew are often the result of moisture being trapped under the linoleum. You should go under the floor, if possible, to check for any water damage under the floor. If this is not possible, you will have to pull up the linoleum to find the problem. Sometimes, linoleum will get a small tear in it, and the floor, especially in kitchens and bathrooms will pull moisture underneath, causing the soft spots. When the spot is found. it will need to be dried, and an adhesive applied to seal the area.