finding sheets of ice in bottom floor of freezer

Love my Maytag bottom freezer refrigerator!!! I have had this refrigerator that I purchased from Home Depot for about 4 years. ice maker stopped working a few weeks after I got it but repairman said the line had frozen up, after he got it thawed I have not had any more problems at all. The last few weeks I have noticed under the mat that is located close to the frig has been having an accumulation of water under it. I traced it to the refrigerator and discovered a thick sheet of ice on the bottom floor of the freezer. I chipped it all out, which was not easy do to the structure of the freezer and drawers, but got it done. Now I see it building up again and again. I am sure there is a leak of some sort that is draining into the freezer floor, but can not figure out where it is coming from or what to do to fix it. I would love some advice or suggestions!!! I absolutely LOVE this refrigerator!!!!

ice on bottom floor of freezer

Just like Carol, I've been having the ice build-up too for a couple years now. My efforts to that and clean anything I can in the freezer have not helped and I have to remove the ice (as Carol mentioned, the task is made more difficult by the drawers in the way) every 2 weeks in summer, 4 weeks in winter. How did anyone fix this???