Many older mobile homes were originally built with floors made of particle board, which is very susceptible to damage by moisture from leaking hot water tanks, toilets and even pet water dishes that can form holes and cause an extremely unsafe condition. When this type of flooring is damaged, removal and replacement with a good grade of plywood is recommended. This is a project that can be accomplished by most mobile home owners without the requirement of specialty tools.
Examine the floor closely. Has the hole developed in one small area or are the holes and soft spots all over? This examination determines whether just one section of the floor will need to be removed and replaced or whether it will require replacement of the entire floor.
Remove the floor covering from the area where the hole has developed. If the hole has developed near the toilet, remove the toilet from the floor and pull up the floor covering. Cut out the damaged section of flooring by locating the floor joist and carefully cutting out the flooring to the center of the floor joist on both sides of the hole. Use a shallow setting on the saw blade to avoid cutting into the floor joist. Make the opening as square as possible.
Check the cut out area with the square and trim out where necessary, using the chisel and hammer to chip out any remaining flooring. Remove all nails and staples remaining in the floor joist. Clean the area with a vacuum or broom to remove all debris. Check the cut out area for squareness and take careful measurements of the size of the opening.
Cut a section of plywood the size of the opening. The plywood must be the same thickness as the original flooring. Test fit the replacement piece and trim any areas to get as tight a fit as possible. Secure the new piece to the floor joist placing the nails or screws 6 inches apart along the floor joist.
Clean around the replacement piece and fill the seams with wood filler. Allow the wood filler to dry and sand smooth. Replace the floor covering. If the repaired area is around the base of a toilet, reset the toilet using a new wax ring.