Joining tapered edge plasterboard question ?

[GlennSpray68]

Hi all ,
I am about to commence drylining /plasterboarding my garage ceiling I've insulated it and put up a vapour barrier and now am ready to fix the boards (whatever they are called !!) to the ceiling .
reading up tonight i've come across a post that totally confused me .
It states that when just filling the joins in the plasterboard (using tapered edge) to butt the boards together with a V shape to allow the jointing compound to have more to adhere to .
is this correct I thought the boards were supposed to go together like a french cleat to give them support and a smaller join ?
also do i fill the V joint (if thats correct then put the adhesive jointing tape on or put the tape on first then fill the joint gap .
lastly my garage is 2.36m wide by 7 m but the ceiling joists run perpendicular to the garage so would i be better fitting the boards(2400x1200) in staggered joints length-ways or parallel to the joists making sure that the joints are on joist centres (the latter way would be easier but one wall is irregular and I would have to scribe each board to fit) is there an easy way to achieve this by leaving a gap at the bad wall side as I'm going to build a stud wall up to that height which will hide the gap .
Apologies for all the questions but i want to get it right first time

Many Thanks in advance for any advice given
Glenn

 

[PrenticeBoyofDerry]

Okay!
The tapers are slightly recessed on the bonded edge of the board (full length way). These but-up together and allow you to apply your joint tape (I use self adhesive nylon type, so they can be stuck on without applying any joint compound to bed them, but if using paper tapes you need to apply a good cover of compound before application of tapes, or you could end up with dry spots).
Once the tape is applied and flattened, you can apply joint compound, normally two/possibly there applications. Letting each application dry and to be lightly sanded before next application. The final application should cover the and slightly over lap the taper of board, and finally sanded down till smooth and even when dry.

The plasterboards, should be staggered and the joists ideally be perpendicular to long side of the board. https://www.zurich.com/NR/rdonlyres...F-4E5D5F270C8D/0/500045004BG900204WebOpt.pdf.

You can fit noggins, for extra support of boards and use 12.5mm boards to prevent sagging.

If the walls do run out of square, I would normally use that as starting point and cut board accordingly at that edge, so the joist run square to board.
But if you are going to fit a stud wall up against this and the unsightly joint is hidden, then go for it.

 

[GlennSpray68]

Hi Prenticeboy , thanks for the answer , one slight problem cannot fit any noggins as have insulated and vapoured? the ceiling now. Do you think if i increase the number of screws on the joists that will suffice ?

Thanks again for your help
Glenn

 

[PrenticeBoyofDerry]

You only need to screw every 150mm-200mm, any more than that will not make much difference.
What distances are the joist separated by? If less than 400mm, you should be okay with 12.5mm boards, it not ideal, not to be able to have at least one fixing screw between joists, but the bonded edge does help prevent sagging.

 

[GlennSpray68]

Hi Prenticeboy ,

The joist centres are 400mm , would 15mm be a better option ?

thanks
Glenn

 

[GlennSpray68]

doh! , thought you could get 15mm boards obviously not . What about running the boards parallel to the joists would that give more support ?

cheers again

Glenn