A mason has just put me some new openings in on a conversion project. The reveals aren't flush as it's natural stone, approx 40mm difference I don't want a huge mastic joint at the side of my aluminium windows/doors.
What's the best method to resolve this? Chisel stone down to right size even though they're insitu? Or chop a channel from the inside so the window frame sits in that?
Any other options would be appreciated.
Cheers,