We're remodeling and the contractor sprayed over the existing holes for our widow shades so I can't find them any more.

I've installed probably over 100 shades and drapes and know what I'm doing - but this time - I'm drilling for top mount brackets and I've hit something about 3/4"-1" deep that is either solid steel or concrete. I can't get a drill through it no matter what I try. Smaller sizes won't go through - I haven't tried a masonry bit yet because I think it's more likely steel though I'm not seeing any shaving of steel or concrete from my attempts to get through this stuff. It's like it's made of titanium or something! The house is masonry built, but the window tolerances should be that tight as to just barely frame the window header.

What can I do????