Lines in Plaster (from Plasterboard?)

wackojackouk

Hi guys

We had our conservatory/extension boarded with plasterboard and then skimmed. Have put on a mist coat and then the first coat (red) and all of a sudden we can now see what looks like the plasterboard lines in certain lights on the main wall (others are fine)

They weren't visible when initially plastered or when when the first mist coat went on (one tiny bit possibly) but now can see more than one and we are worried they are going to show when we've put on another coat or two.

Can anyone suggest what could cause this (too thin a skim?) and what would be the best thing to rectify it before we go any further.

Cheers

WJUK

ormus

maybe drying out too quickly.
sometimes you always get this problem in a certain light. as the joins are thinner and expand/contract at different rates to the PB, you can get the sight lines.
but only at certain times/light/colors.

wackojackouk

Thanks Ormus

I'm going to put some more coats on shortly anyway as it's a little patchy (normal for first coat). - There is one more prominent than the other and IIRC the board might not have been 100% flush (it wasn't pointing out or anything but the gap seemed a bit bigger than the others).

Was wondering if it was worth getting another skim on top?

Otherwise coats and pictures to hide the lines and you're right in bright sunshine you can hardly see them... wonders if Red was not the best colour to use as was hardly noticeable with the white mist coat.

Funnily enough the back wall has the same pb, joints etc and is perfect.

keystone

Were the joints taped? Did your spread apply two coats of skim? If he didn't he should have done. Applying another now over the paint will be challenging TBH. As Ormus suggests it could just be the light.

Cheers

wackojackouk

Joints were definitely taped. Not sure about 2 skims although he knows what he is doing so I would have thought so. I presume 2 skims isn't doing one on one day and coming back another day to do another?

IF we did want another skim added, would it not be a case of just scoring the paintwork on that wall, adding some PVA and reskimming or am I talking rubbish lol - I am just guessing from reading other stuff in the past.

Cheers

WJUK