I've just plaster boarded up a ceiling and while doing so realised that plasterboard sheets seem to have shrunk? 

First I thought it was either me or my tape measure and then I twigged the sheets are all actual 2395mm and not 2400 long - my mistake was not taking this missing 5mm into account when I cut short ends of the plasterboard. So rather than waste a load of sheets, I now have some very annoying gaps in my ceiling.

Main question is: what should I fill these gaps with? Drywall join filler or some expanding foam? My sense is drywall filler is more sensible.

The other thing I also realised is that all my sheets are 3mm less than 1200mm some along both the walls and ceilings the screws get closer and close the batten/stud edge.

Is this sheet dimension new or have I just been blind to it before?

 

 

Edited April 15Apr 15 by SimonD

I thought all plasterboard sheets were about 1/4 inch undersize - I assumed you were supposed to leave a gap to push plaster into (I’m def not a plasterer).

5 minutes ago, markc said:

I thought all plasterboard sheets were about 1/4 inch undersize - I assumed you were supposed to leave a gap to push plaster into (I’m def not a plasterer).

 

Clearly, I've never measured them properly to begin with 🙄 My assumption was that as with timber products which is what I'm more used to working with, or pipes, you get what's specified. And maybe it explains why I had to get rid of the plasterer I was using? I was just told that gaps above 3mm must be prefilled, nothing about leaving a gap when boarding but he and another did most of the boarding so far. Oh dear!

I think they're always a bit undersized. They're always designed to be filled or skimmed so suppose it makes sense to be smaller rather than bigger. 

If they are too tight they will snag and you will lose edges, esp if you need to take a board down etc.