If you are talking about the exterior frame, suggest you to Wrap them up with metal sheet, once and for ever (may be I shouldn't say for ever, should say for a long time) Painting lasts only a few years.
I have a lot of experience with painting. Please call me at 780-604-6133. My name is Man. I speak Cantonese/Mandarin. 9 u! S/ U8 D; l+ `; |) O4 z. ^' X% M% N5 j0 D
Look forward to hearing from you soon. Thank you