Plasterboarding ceiling with metal shoe at end of joists

[Omnibuswoman]

I have noticed that the bottom of the metal shoes holding the ends of the I joists are slightly below the level of the joists themselves. I'm shortly going to be plasterboarding the ceiling, and wondering how to overcome the difference in depth. Should I cross batten the whole ceiling to create a level surface, or shim the face of each joist with something of the same depth (around 4-5mm), or just not worry about it? I've noticed that if I screw PB into a surface with a raised point it makes stress noises - what I don't know is how much this matters....?

[crispy_wafer]

have you ran a straight edge across the i joists, are they perfectly flat?  Mine weren't, out by a few mm here and there.  So I ended up cross battening and packing to take out the undulations, this also removes hangers and nail heads from the equation.

Edited 9 hours ago by crispy_wafer

[Nickfromwales]

If you don’t want to lose the extra inch, you could use resilient bars. If there’s a floor above you’ll kill two birds with one stone; levelling and avoiding the humps, and getting sound sound deadening.

 

Defo not a good thing to try and screw PB to two different levels, with screws so close together. The screws will just keep breaking through and the plasterboard stands a chance of snapping too.

 

Resilient bars will drop you about 15mm iirc. 

[Big Jimbo]

I normally run 20mm cross battens. Spacing them to take the plasterboard sheets.

[Oz07]

What are you having tape and fill or skim? Skimmed boards can be fitted with a few more lumps and bumps than the former

[Oz07]

Those hangers don't look bad to me from the picture. I'd be inclined to board over. Sometimes a flat bit of timber and a whack with a hammer flattens it out. 

[torre]

Unless you need fire protection I'd be tempted to take a couple of mm off the back of the board where it would contact each hanger.

[Omnibuswoman]

Thanks all for these replies. I will check how level the joists are to decide whether I need to batten or use resilient bars, and I will give bashing one of them a go to see whether I can reduce the difference enough to just PB straight onto them. 

[Mr Punter]

The res bars are good call. Easy to fit as well.