I used Soudal PU adhesive foam to line a plastic shed with polystyrene insulation boards recently. That might work in the context you describe, but you have to allow several minutes after application for it to get to the right stickiness – then you have to hold it in contact for a minute or so. That squashes it flat between the surfaces, which seems to accelerate the curing of the cyanoacrylate component. Might be worth a try on one or two boards before buying in quantity.

Don't know about passivated plasterboard screws but would stainless not be better to use in the bathroom? Niko.

For a completely different alternative consider the tongue and groove plastic panels normally associated with shower enclosure walls.

After using them for the ceilings on a full tile bathroom re-furb I was impressed enough with panels from IPSL, **LINK** , to do the whole house with them as part of extension work. Mostly white but with coloured patterned ones where I felt appropriate!

Wipe clean and no painting, papering or other messing about for years to come.

Staple straight to plasterboard or plastered ceiling. The electric stapel gun from LiDL did me just fine.

I used plain white bath et al sealer round the edge in the bathroom and kitchen which were tiled right up to the ceiling after installing the panels. Dark stained 1/4 circle scotia moulding hides the to wall joint in the living area. I have old style picture rails around 16 – 17 inches down from the ceiling level with the tops of the door frames with plain white painted plastered wall above. The proper way to do things when 8 ft ceilings were the norm.

Clive