Plasterboarding over old ceiling

[That looks tricky]

I've got a bedroom ceiling thats pretty rough due to age and past water leaks, and want to re-board it. Is there a smart way to find the joists above, or do you just get in the loft and poke a hole down into the room to show where they are?

Thanks

 

[Gary0]

You can buy detectors from the DIY store. I've found they can spot joists if you sweep enough times, but seem to be rough guides to me. I've always tended to end up going into the loft and drilling small guide holes either side, in various places along the joist, just to be sure. But maybe that's a confidence thing on my part.

 

[That looks tricky]

Cheers Gary - I hadn't thought of drilling either side - that sounds foolproof and I only want to do this once! I'm planning on getting the whole room skimmed, including the new ceiling - do you know if I should use square or taper edge boards?

Thanks