Cutting plasterboard that is installed.

[curium]

Hi This is part of my on-going bathroom renovation project, I'm gonna post it up in the 'Your Projects' forum.

I've removed the tiles on my bathroom wall and this has caused damage to the plasterboard in places so I've taken a lot of it off the studwall with the intention of replacing it.

Here's a picture;

Unfortunately there isn't a natural edge where the two pieces of board could join that would give me a nice straight alignment when I hang my replacement plasterboard alongside.

I'm reluctant to remove the plasterboard back to the architrave simply because I've never removed an architrave before.

I figure the best course is to cut the existing plasterboard to give as straight an edge as possible and then fit a tapered edge plasterboard alongside it and fill to make it level.

Is that the best course of action? If so can you advise on the best way to cut the existing board to give a straight edge while it's hanging. Are there any special tools of the trade?

EDIT - I forgot to mention that the plasterboard in the bathroom is all 15mm.
Cheers!

 

[gday2uk]

If you've never removed architrave before now is the perfect time to start learning. Run a knife along the paint lines of the mitre and door lining and lever it off, that way you'll be able to reuse it. You'll have to remove the board up to a point where the edge of old and new join on a stud either vertical or horizontally. You can't have a joint floating as it will be too weak. Also if you take the whole wall down you can put back up whatever thickness board you wish. Refix the architrave to the door lining after plastering.

 

[curium]

Cheers gday2uk!

If I removed the architrave edge would I find that it is on a stud? Also is the section of plasterboard above the doorway likely to be a separate piece as opposed to being part of the plasterboard to the right or left of the doorway with a piece cut away for the doorway?

Finally Could I not just insert a wooden stud in the tracks near the edge of the existing piece of plasterboard and then neaten up the plasterboard edge and nail into the newly inserted stud?

I really am worried about breaking that architrave but may buy a crow bar and have a go at it if that is the best way.

 

[Richard C]

Unfortunately there isn't a natural edge where the two pieces of board could join that would give me a nice straight alignment when I hang my replacement plasterboard alongside. I'm reluctant to remove the plasterboard back to the architrave simply because I've never removed an architrave before. I figure the best course is to cut the existing plasterboard to give as straight an edge as possible and then fit a tapered edge plasterboard alongside it and fill to make it level.

You need to join the boards over a stud to give it any strength or in all probability it will crack the first time someone leans on it & FFS don’t use taper edge & fill it out! The architrave should come of fairly easy; break the “paint edge” between the door lining & the architrave, tap in an old stiff scraper & gradually prize the architrave off. Remove all the boards from the existing stud & replace it. Don’t use ordinary PB in wet areas (shower or behind the bath), use either Moisture resistant & tank it or a waterproof tile backer board otherwise you will only have problems in the future which it sounds like you’ve already had. If you’re renovating, strictly speaking, the work should comply with current regs. which require sound insulation (Sound Block boards & mineral wool insulation) between any rooms containing a W/C & other habitable rooms but if you’ve no inspection work involved, you’re unlikely to get found out!

Is that the best course of action? If so can you advise on the best way to cut the existing board to give a straight edge while it's hanging. Are there any special tools of the trade?

Do it properly; I would remove, re-board using square edge boards & RE-PLASTER any boards that are visible (not behind tiles or if you use tile backer board). I would also advise you read through the archive posts in both the Plastering & Tiling forums before you go any further.

 

[curium]

Cheers Richard C!

I'll get started on removing the architrave then. Am I likely to find a stud behind it? What about the plasterboard above the door frame, will that be a separate piece?

You say I should get the plasterboard plastered, I am getting a plasterer in to skim the artex on the ceiling so I could ask him to do the boards also. Problem is, the existing plasterboard that you can see in the picture is painted. Do I need to have the existing boards plastered over the paint? If not won't the new boards be slightly proud of the old ones once they've been plastered?

 

[gday2uk]

Cheers Richard C!

I'll get started on removing the architrave then. Am I likely to find a stud behind it? What about the plasterboard above the door frame, will that be a separate piece?

You say I should get the plasterboard plastered, I am getting a plasterer in to skim the artex on the ceiling so I could ask him to do the boards also. Problem is, the existing plasterboard that you can see in the picture is painted. Do I need to have the existing boards plastered over the paint? If not won't the new boards be slightly proud of the old ones once they've been plastered?

You should find stud work encasing the door frame. The plbrd above the door will probably be a separate piece (no knowing though).

You will have to have the entire wall plastered, it would not cost any less to leave a bit once he's started.

 

[curium]

You will have to have the entire wall plastered, it would not cost any less to leave a bit once he's started.

Just to confirm, I can have the painted plasterboard plastered without a problem?

I'm going to tile wall to ceiling around the bath but the other half of the room we're undecided. We may decide to tile up to window height and then paint from there to the ceiling.

Is there any benefit to be had from plastering the water-resistant plasterboard I'm planning to install around the bath? That area will be tiled anyway.

Cheers lads! I'm asking so many questions so as to avoid cocking up, I really want to achieve a good finish. Think of it as a variation on the old adage measure twice, cut once.

EDIT- Sorry lads, another query. Apparently Gyproc Moisture resistant is only available with tapered edge in 15mm thickness according to their site.

 

[Richard C]

How much PB is on the other side of the door? For the small amount of additional work involved, in all honestly you may as well take the lot down & start again. You can then use 12mm square edge board over the lot, avoiding any problems with difference in levels. Tape the joins, you don’t really need to plaster the boards where your fixing tiles but I usually do as it’s easier to plaster the lot than feather the edge away into the area being tiled, the cost difference in both time & materials is minimal; there is a an argument that plastering under tiles reduces the adhesion strength but I’ve never had tiles fall off yet, even large ones! DON’T FORGET, either tank the plasterboard (even the moisture resistant stuff) in the wet areas before you tile or (preferably) use a waterproof tile backer board.