Buying Toilet, But How Do I know It Will Fit?

[just pumps]

Is it easy to make a false wall with plasterboard, if there's a gap to fill?

Batons and plasterboard easy job

 

[Lord Snooty]

I wouldn't need to skim it with plaster?

 

[blup]

Is it easy to make a false wall with plasterboard, if there's a gap to fill?

Relatively easy but it depends on your skills and the layout of the room/wall in question.

You would fix a series of battens to the wall the depth required allowing for the thickness of the plasterboard.

Blup​

 

[blup]

I wouldn't need to skim it with plaster?

Not essential but skimming would give a finish consistent with the rest of the room, and cover the drywall screws and any gaps between boards, maybe not strictly necessary for a small section of board.

If tiling, I believe no need to skim.

As a DIYER I would be happy to give it a go.

Blup

 

[JohnD]

If you're only talking about a gap between the cistern and the wall, it might be a hundred times less work to just make wooden battens to fill the gap (maybe recessed in from the top and sides of the cistern for elegance) and painted to match the wall or the cistern.

You've decided not to show us any photos, then?