Tx, my
is to replace the screws with a larger diameter screw. If the washers have deteriorated then the screw holes are probably wallowed out also from thermal contraction and expansion of the metal. Screws will last as long as coating and you will be able to repair easier if there is a problem down the road. Several coats of coatings will look like dodo after a couple times of application.
...but hey, thats my
Metal Roof - Seal or Rescrew
Linear Mode
