Fixing upvc windows

[Gossamer]

Evening,
I’m installing upvc windows in my house (going through BC) and have hit a hurdle.
Got the first in and packed then drilled through the frame and hit metal. Got a hss bit and went through but it’s occurred to me that maybe I’m fitting incorrectly.
There were a load of metal ties that seem to fit into grooves in the window frame.
Can anyone enlighten me?!
Ta.

 

[crank39]

The ties are called cleats, used for speed fitting usually new builds where there is no internal plaster, the frame fixings then screw into the internal skin and plastered over, if your drilling through the frame into the outer skin then remove the cleats

 

[Gossamer]

Is it normal to have to drill through metal in the frame if I want to use frame fixings?
I didn’t expect it.
I’d prefer to use frame fixings but the metal seems quite thick.

 

[crank39]

Yes reinforced frames are good, still many sold that aren't that said steel reinforcing is being phased out in favour of reinforced plastic, all about reducing the heat sink through the frame. Using an SDS drill with a masonry bit shouldn't give you any problems at all, are you using concrete screws or sleeved fixings like Fischer's?

 

[Gossamer]

Using frame fixings, 100mm long plastic plugs. Concrete screws don’t work in my old brickwork.
I did one hole.
Masonry bit didn’t work.
Needed an 8mm HSS bit to get through the metal which unnerved me….