Out of Square Wall

[leevis]

Hi
I have knocked a dividing wall out between a toilet and a bathroom and need some help regarding the squareness of the walls.
Basically, the wall is not square so I will need to level these out somehow. I would rather not use plasterboard as that would reduce the size but not closed off to this solution.
The entire dimensions of the new bathroom are 2.4m square and one of these walls is about an inch out meaning that I would need to bring it out an inch (maybe less) to get it square.
I was thinking of plastering each wall as they aren't in the best condition (removed tiles, blown plaster etc) so they really need a good skin.
What would the best way be of doing this (will be doing it myself).
There is a window, bath waste pipe and toilet pipe on this wall.
I was thinking about dot and dabbing some plasterboard to this wall to bring the actual distance I need to plaster down a bit, is this a good idea? Otherwise I could just plaster and big thick amount and level it up using battens etc.
Ultimately it will be tiled (probably floor to ceiling) so I don't know which way to go, plaster or just do the plasterboard method and then use grout to bring it up.
Any ideas?

 

[leevis]

Been thinking about this and I think that the best solution for me would be to secure some plasterboard to the wall where it is out (about half of it). I have some 12.5mm board so I will get some of that up, also I have some 9mm which should do the trick. The question I have is how to secure this to the wall. The wall at the moment is half bare (where the old bath was) plaster and the top bit is painted in acrylic.
Should I screw it in and plug the first layer and then screw through this for the second? Or dot and dab, if so do I need to prepare the surface?
The plasterboard that I am putting up will ultimately be skimmed to get flat before tiling.

 

[ree]

Are you saying that you have a return wall(s) that is not 90 degrees? Or are you saying that you now have "one" wall that is not flat?

Pics will always help your cause?

 

[leevis]

I have a bit of both really
I problem wall is about 2.3m in length and has a small window on it which used to be the toilet room. I can only assume that both of the rooms were re-plastered at some point which has meant that the small end (toilet) is thicker that the longer end.
Using a straight end I can see that the long end is about 15mm+ out. The 90degree corner isn't too bad and I can probably skim this to true it up.
Really unsure what to do on the long wall. I can either screw plasterboard to the wall and skim or I could destroy the plaster that was put on the short end and then reskim it up. As far as plastering goes its probably going to be less plastering to destroy and then replaster to short bit (about a meter) but then I have the work of removing the plaster. That being said, previous owners have plastered the inside of the window not square do I will need to remove plaster from the reveal anyway. Ultimately it will be covered floor to ceiling (the plan at the moment) in tiles but if I can get it looking good I will only tile half way up.
Reduce the short end or plaster the long end is the conundrum here.

 

[ree]

Given that you are starting from scratch your best bet would be to hack off the plaster to brick on the "long wall" and the short return wall.
Then render up in sand and lime or a S&C mix - this will protect the bathroom (wet room) walls from damp and enable you to have perfectly plumb flat and true 90 degrees surfaces. Use plastic angle beads for outside corners.

Skimming is not the answer as a background for tile, esp large modern tiles. Any painted plaster should be skimmed of course.

First fix and paint the ceiling before any rendering.

 

[leevis]

thanks for the advice on this one, much appreciated.
I feel that I might have confused matters here on this one.
Basically I have a wall that is 2.3m in length which used to be the bathroom, then a wall, and then the toilet. The wall has been removed which means I now have a great expanse of wall to tile. the problem is that at some point, the toilet area has been replastered meaning that the level on this end of the wall is about 5-10mmm higher that the other end. This means that I have a reasonably flat wall for about 1.8m then another flat wall for the final .5m but its higher/thicker than the other one.
For ease I think I will chop out the extra thickness from the high bit and then do a bonding plaster job on it to get it level, would this be the recommended method? Seems easier to focus on the least area rather that build up the larger area to match.
Also, how much wall outness can grout hide? is there a limit like 5mm? I don't think I am ever going to get this one perfectly flat but need to work out when it is 'good enough' to tile
L