Lowering 1cm of about 1 m2 of screed

What type of door is it, timber or uPVC?

 

What’s the gap on the door head like from outside?

 

A 1cm step is a guaranteed trip point. If you possibly can I would try to create a very gentle slope to accommodate the change in level. You can shift a lot of screed quite quickly with a scabbling bit in an SDS hammer then tidy up with a diamond flattening disc in a small grinder. The dust will be horrendous though - or worse than horrendous...

 

The floors not level though surely? There’s a decent gap between bottom of the door when closed but bugger all when it’s open? The door can’t be out of plumb that much otherwise it’d be swinging open with a crash all the time.

 

My first thought this morning was hiring a floor scabbler but I wondered if the door could be bumped up to save all the hassle. Dust will be like Hiroshima.

 

Post a photo of the door looking at it from the outside.

 

As I see it, you’ve four choices, three really but there’s always room for a Joker. Or a combination.

1. Knock the plaster off the lintel above the front door and see how much room there is to play with. Remove the door and frame from the opening, stick it on a bench and remove a quarter inch from the top of the frame by handsaw and a power planer. Refit the frame bumping it up as tight as possible, then see what clearance you’re left with on the lintel and on the floor. Bluegrit the lintel and skim over.
2. Use a long level across the screed and see if there’s a sharp bump where the door opens onto, or if the whole screed is running gradual towards the front door. If it’s a bump, chisel it out and rescreed it at the lower level, if it’s gradual, onto the next plan.
3. Hire a floor scabbler to grind the screed down. Mess and dust extraordinaire.
4. Mark out a metre or so from the front door, chisel the screed out and fit a different tile, oak floor with an inset doormat, leave the screed and fit thin vinyl instead of thick tile to hide the issue and create a feature etc, though this will depend on the style of the house and whether you can make it look good with choice of material rather than naff.