Kitchen ceiling plasterboard help!

Kitchen ceiling is 16ft 4 by 11ft 7 and joists run parallel to the long wall. I've been advised that its best to stagger sheets with their long edge at 90 degrees to the joists. 6ft x 3 ft would suit me to collect in my car (I live in a rural area) but that would mean something like having a 6ft and a nearly 6ft board for one lenght then a 4 x 3 x 5 on the next? If i use 8 x 4 I can do it slightly differently but then i have a 4 inch wide for the last length? Can i mix widths or can someone tell me how best to do this? if i need to i can get sheets delivered. I intend to use 12.5mm fire rated but does anyone have any advice on best way of fixing and brand of tape to use? Also any suggestions for solid/soundproofing insulation appreciated. And finally square edge or tapered?

8x4 sheets aren't that size.
They are 1200 x2400 which is smaller.
After finding joists you can work out the best way to board, and you can start by cutting some off so you aren't left with 4 inches at the end.
You can also add timber if needed to support the boards to make it fit.
I hire a board lifter when I use 8x4 sheets.
It's about £55 a week and worth every penny. Why struggle...

Square edge if you are plastering.
Tapered edge but buy the 4 sided taper edged board if you are taping just the joints.
You won't get that from DIY.
Two sided tapered edge boards are for house walls, which Is what the tapered edge is just on two sides

Rojomateus said:

Kitchen ceiling is 16ft 4 by 11ft 7 and joists run parallel to the long wall. I've been advised that its best to stagger sheets with their long edge at 90 degrees to the joists. 6ft x 3 ft would suit me to collect in my car (I live in a rural area) but that would mean something like having a 6ft and a nearly 6ft board for one lenght then a 4 x 3 x 5 on the next? If i use 8 x 4 I can do it slightly differently but then i have a 4 inch wide for the last length? Can i mix widths or can someone tell me how best to do this? if i need to i can get sheets delivered. I intend to use 12.5mm fire rated but does anyone have any advice on best way of fixing and brand of tape to use? Also any suggestions for solid/soundproofing insulation appreciated. And finally square edge or tapered?

Click to expand...

16ft 4in × 11ft 7in is approximately 4.98m × 3.53m, giving a ceiling area of about 17.6m².

A 6×3 sheet, approximately 1800 × 900mm, covers 1.62m². The bare area requires 11 sheets, while a 10% allowance takes the purchase estimate to 12.

An 8×4 sheet, 2400 × 1200mm, covers 2.88m². The bare area requires seven sheets when rounded up, and it remains seven with a simple 10% allowance. However, the joist positions and usable offcuts could still make eight the safer cut-list quantity.

The larger boards reduce the number of joints but are considerably harder to handle overhead without two people or a board lift. Whichever size you use, mark every joist first and draw the complete layout so all board edges are supported. Shift the starting cut if necessary rather than leaving a narrow four-inch strip.

This is a useful calculator

https://buildcalcs.uk/plasterboard-calculator

It provides a purchase estimate, not the fixing layout. Board type, fire performance and fixing details should follow the manufacturer’s guidance and any applicable building requirements.