Landing ceiling joists massively out of level, all directions, best way to level?

[User1234567890]

So, I've bashed all the ceiling plaster and old boards off, back to the joists, on my landing and as always, there's something holding me up. There are 4 visible joists, all at different heights. There's a 40mm difference between the highest and lowest spots, along one wall alone. The loft hatch is a big chunk of the ceiling, and that protrudes further than the joists by about 12/13mm ish. Normally, I'd just get it looking somewhere close and have done with it, but I've got to make a big cupboard above the stairs once the plasterboards are on, which will look a bit crap if the ceiling isn't bang on.

My plan was to cut some wooden battens to approximate size and screw them on using plastic packers to get it level. I know what a ballache this is to do, as I have done it before, especially overhead on a little landing, so I thought I'd ask here first, if there are any easier ways.

I saw something about metal battens, but how would they be any easier to get level? Just stick with the wood and plastic? Any suggestions, much appreciated, cheers.

 

[Wayners]

There are a few ways to do it but last one I leveled I screwed timer to the sides of the joists.
I used a plank cut down along the middle.
Use a cheap laser level set at around 1m high or on the window sill.
That shines on some batten of wood with a mark on. Set that up with the top of the batten at the lowest point with laser on the mark.
As you move batten around with the laser on the mark, then the top is the height you are working to.

You can also cut ply and fit either side of joists. Cut wooden blocks to fit in the centre to fix board to.

 

[User1234567890]

Thanks mate. I'm liking the laser level idea, I do have one, but the loft hatch frame was blocking the beam from a lot of the ceiling, so your idea with the mark on a piece of wood should fix that. I had already filled between the rafters with PIR as all the insulation that fell out was knackered, and it is boarded above in the loft, so it seemed like the right thing to do, and don't really want to undo it. The laser wasn't happy with all the foil tape everywhere, either, so another thumbs up for your idea. Will give it a try tomorrow, cheers.