Fitting Drywall

[Munroast]

Putting tapered edge board up, (just the tapered bit gets taped and plastered.

Does it matter if there is a couple of mm gap between boards ? or is it important that they butt together. I'm thinking the plaster will fill a 2 or 3 mm gap. Also the bit that goes up at 90 degrees to another wall. does it matter if the tapered bit goes here? obviously with one wall it will have to be cut to squre edge, but is it best to do both walls like that ?

 

[RandomGrinch]

Only a DIY'er, but

Does it matter if there is a couple of mm gap between boards ?

Nope, doesn't matter!
A spread of jointing compound goes over the top of the joints, before laying the tape in. A gap of a few mm will be fine.

For the non-tapered edges, you can get a good joint by chamfering the board edges with a rasp; forming a V to contain the filler, without the need to tape.

Also the bit that goes up at 90 degrees to another wall. does it matter if the tapered bit goes here? obviously with one wall it will have to be cut to squre edge, but is it best to do both walls like that ?

I prefer to get a straight edge against the wall, as it feels like a waste of effort to fill and sand an entire taper, that's not on a joint!
However, if your tapered edge ends up against a ceiling, and you intend to use coving - go ahead - you won't have to touch the taper!

I hope that makes sense!

 

[Munroast]

For the non-tapered edges, you can get a good joint by chamfering the board edges with a rasp; forming a V to contain the filler, without the need to tape.

45 degrees half way through, making the V about 12mm at its widest ? and without tape would these not crack.

I prefer to get a straight edge against the wall, as it feels like a waste of effort to fill and sand an entire taper, that's not on a joint!

would you go as far as when putting the stud wall up, to arrange the first stud so as to having to cut the taper edge off?

 

[RandomGrinch]

45 degrees half way through, making the V about 12mm at its widest ? and without tape would these not crack.

I haven't had any issues with cracking on a ceiling, or walls. But I have got quite decent Victorian floor joists, with very little movement.
Although, just rereading some past posts on here, it does seem to be discouraged.
I think the decider for me, was it was easy to do and gave a decent result; and if there were cracks later, I could always redo with tape.

would you go as far as when putting the stud wall up, to arrange the first stud so as to having to cut the taper edge off?

My first priority would be to minimise wastage; if I could do that and cut down on filling, that would be a bonus!

...and I would recommend using a bare plaster sealer, or Zinsser Gardz to seal the filler before decorating.
I find it toughens up the filler nicely, when a mist coat can sometimes reactivate the filler and get a bit messy.