How to resolve a rusting uPVC window fixing torx screw?

Question

The window in this property has been fitted with steel screws, all of which have rusted as the window is often open and inevitably moisture has reached the screw heads. My goal is to replace them all before the heads are corroded so much they cannot be removed in future. All the flat-head screws have been successfully replaced, but to the right of the frame you can see a single T30 torx screw head which is significantly corroded.

Should I:

A. Remove the T30 screw and simply screw in a corrosion resistant equivalent of the same dimensions?

or

B. Leave the screw where it is, but treat the screw head to prevent further corrosion?

My hesitation relates to what exactly the torx screw is screwed into, as I suspect some of these fixings come with a plug assembly that the screw may be screwed into and I don't want to remove the screw and find I cannot drive a new one in. A rusted screw head (with corrosion resisting compound on it) is probably better than no screw at all!

Answer 1

I think I would see if I could remove the rusting screw. It boils down to, it is never going to be less likely to break off than it is right now. If you're lucky, you could coat it with silicone, seal out the air, and it won't get any worse, but that's just the head - the shaft may continue to deteriorate.

I'd try to get it out with just the torque I can work up with a screwdriver with a Torx bit, if I couldn't get it out by hand, I'd leave it.

I'd also try to get some penetrating oil on it, although it may be tough to get it past the head and down to where it counts. Also tap down on the head a little with a hammer to vibrate it a little, this often helps break a stuck screw free.