I had a wooden back door removed and replaced with a metal door following burglary twice. The workmen have left an inch gap between the wall and the door frame both internally and externally. What is the best material that can be used to fill this gap all around the frame? Can someone help please?
A 1 1/2" gap is pretty big and its possible that it was poorly fitted or poorly installed. I would have expected the workers to filled this and installed trim to finish the installation.
Generally speaking, you would fill this gap with an expanding foam meant for windows and doors (Great Stuff is a well known product for this).
But back to the large gap, the first thing I'd look at is if it's uniform around the door. Having a 3/4" gap on both sides wouldn't be as much of a problem, but if you have a large gap on one side with no gap on the other, my suggestion would be to move the door so that you have an even gap, and then proceed to fill the gap with expanding foam. You will want to add trim around the door after to finish it off, and then caulk the gaps where the trim meets the house and the door.
If it's a hollow metal doorframe, it's generally intended to be filled with a cement mortar mixture, and I'm surprised if the job was considered complete without doing that. I've lived in a cheap apartment where they didn't bother to do that, and was burgled since the unfilled doorframe easily flexed far enough away from the door to clear the lock bolts when the thieves pried it.
I suppose it's also possible that it's simply the wrong size door/frame, in which case filling in with material similar to the wall (right - the title says bricks, so split bricks and mortar) might be appropriate - or getting the right sized door, but that's a step backwards.
That building was so poorly constructed that a few years after I moved out, the roof tore off in a thunderstorm (it was not a tornado.)