Leaks and lose screws

I had a 26ga. Ag style (exposed screw) roof installed in 2013 to replace three tab singles. 30lb. synthetic felt is on the 1/2" 5 ply roofing with the metal attached with 1-1/2" sheet metal screws. In 2016 I noticed water marks around several protruding screws. In 2017 the contractor retightened screws and 2018 they went from seeping to leaking. I have a proposal to replace all 3000 #12 sheet metal screws with #14 metal to wood screws and epoxy any that do not tighten. Will this provide a leak free roof for 30 to 50 years? Or do I need to replace with standing seam?

Seems that no one wants to touch this problem with an experienced answer.

Don,

Have you contacted the panel manufacturer? They would be the first person in the chain of custody to tell you what is recommended and an approved practice.

Exposed fasteners are a very installation sensitive application and the range of error from under tightened to over tightened is pretty broad an covers a good bit.

In most cases where screws are being replaced, you remove the screws, go with 1 size up screw, and use a proper gasketed screw.

The fact that the roof is leaking after not quite 6 years is more indicative of a questionable installation than anything. I am not sure that I would have the same contractor out that installed a roof that has now leaked twice to attempt it a 3rd time.