Stupid plastering error

It won't make any difference.

Reminds me when I had put up some plasterboard a few years ago and had a plasterer come round to plaster it. He said, "by the way, next time put the plasterboard on the other way round". I pointed out that plastering onto the aluminium foil was probably quite a bit more difficult, which he conceded ;-)

It comes from the days when the scrim used was hemp. You put a layer of hemp and plaster along the joints to stop them cracking. This thickness is still allowed for on the grey side of the board. With modern fibreglass masking, there is no need for that extra step.

You did use something across the joints? (Just a little kick in the pants. It's not a major catastrophe, especially if you are tiling.)

Lol, a common mistake, when they manufacture the board, the liquid plaster filling is poured onto the lighter paper and it binds with the paper fibres, the darker paper is then layed on top with the lighter sides folded around and glued. The bonding strength of the darker paper is below specification and is NOT for sticking ANYTHING onto it, especially something wet that soaks through the paper to the plaster filling weakening the tiny area around the nail or screw used to fix the board to the surface.

Thats why they take the time and money to print the words "Plaster other side only" onto plasterboard.

On a ceiling with heavy light fittings fixed to the board with condensation or a water leak could bring the ceiling down, but in your wall/tile situation it will be fine, just dont fix anything heavy like shelving to the finished wall.

In message , Michael McNeil writes

Hmm, so why would my square edged boards that I recently used bother to say it? Since there is no difference in thickness?

Anyway, I thought to point of taper edge board (which I presumed you were talking about) was for those situations where you are just filling the joints and smoothing off, not skimming.

But surely you would be fixing shelve etc. to the studs, not raw plasterboard ?...

Err, yes I would but you wouldn't believe what some people do, like the hole in a stud wall I was asked to repair where the loudspeaker bracket had once been fixed before it and the large heavy loudspeaker fell off onto the girl sat underneath.

The subject says it all really. I need to ensure that the join is airtight and able to resist only 5" water pressure.

I tried looking this up on the WWW, but did not get much help.

Try a boat shop. They will have various adhesives for this type of application.

Slicone rubber for selaing. It adheres well enough probably.

Or us l angle bolts, screws and sealant.