Painting over thermo foil will not be a long term solution. It is a smooth non-porus material. Your best bet is to replace the doors. There are lots of options today that weren't available a few years ... read more
John
I would do what Paul said but I would take an additonal step of capping the sprinkler heads where they are easy to get to with a half dozen of 1/2" PVC caps. Then you are increasing the pressure ... read more