Accuracy of plasterboard cut.

Stanley knife - easy

A small surform plane is just the trick for trimming plasterboard down, e.g.

Any sort of wood rasp, in fact. The most difficult part of the job is lifting and placing the sheets. If you have tried to be too clever in fitting neatly, it will get stuck and you may break your nice cutout. You can go about a centimetre oversize and still fill neatly afterwards. Do you mean a soil stack?

Yes it is a soil stack. I have a small surform plane last used 20 years ago :-) I only rediscovered it a couple of weeks back.

you can rasp the oversize bits away.

In any case you don't want to fit too close to the pipe - need a bit of expeansion joint

leave 4-5mm gap and seal with decorators caulk.

Make yourself a dead man, makes ceiling so much easier:

In message , John Rumm writes

Interesting idea, but are those measurements really correct? The prop is room height plus 50mm plus the depth of the cross piece, plus the thickness of the board? Will that really spring into place?

Yup, the 2x1 at that length is fairly springy. Just lift the board and shove the prop under it (in fact you can lift the board using the prop partly - a gentle kick will wedge it lightly in place. You can then reposition the sheet as required and spring the prop in more firmly when you are happy with the position.

Sorry chaps! For some reason, I had read the upright as 2 x 2 and couldn't imagine it having enough flexibility. 2 x 1 makes perfect sense :-)

FWIW A bit of tile batten works ok as well...