We have a metal sliding door with fixed side panels leading out to the garden. I have noticed that on the inside, where there are horizontal flat “ledges” to hold the pane (none on the outside), rust is starting to bubble through. There is none on the vertical parts of the frame (I included 1 image to show how the vertical side is unaffected) . I assume it is because moisture has pooled on the horizontal
Any advice on how I should tackle this?
ps the doors were installed 15 years ago. This problem has stayed to surface in the last year or so.
