New plaster and bathroom paint

TomsMom

maccistani wrote: »

For new plaster, either use the cheap value emulsion, or even better, some PVA to seal the plaster, then you can use any paint on it.

No, don't do it!!!!!!!!!!

Misgrace will come along soon I'm sure to explain properly but don't PVA your new plaster. Seal it with a mist coat. If you use PVA your paint will probably flake off. Same goes if your tiling. The adhesive will make the PVA live and the tiles wont stick properly.

Misgrace - please come and explain the techy bit, I know not to use it but not good at explaining why!

maryjane01

I made the mistake of putting bathroom paint direct onto plaster. Don't do it, I don't know anything technical about paint, but it all went horribly wrong and ended up sanding lumpy paint off the walls.

misgrace

Andrew, here is a little tip with the filler.

As you have filled onto the bare plaster, and I do that first, in theory, the plaster shouldnt need filling :rolleyes: but it always does, plus you have to sand down the 'nibs'
After you have sanded the filler, get some diluted emulsion, and brush on the filler a couple of times.
The roll as normal, if you roll straight over the filler, then even after 3 coats you will see the filler flashing through your coats, this way, 'spotting the filler' will avoid any flashing.:D

misgrace

TomsMom wrote: »

No, don't do it!!!!!!!!!!

Misgrace will come along soon I'm sure to explain properly but don't PVA your new plaster. Seal it with a mist coat. If you use PVA your paint will probably flake off. Same goes if your tiling. The adhesive will make the PVA live and the tiles wont stick properly.

Misgrace - please come and explain the techy bit, I know not to use it but not good at explaining why!

Lol TomsMom, I'm not too good at explaining either but I will try.

PVA should never on any circumstances be used on new or bare plaster.
Plasterers are the only ones who should use it when they are plastering.

When there is new /bare plaster, it needs to be sealed and penetrate through to the plaster, if you apply diluted PVA onto the new plaster it will not penetrate through, but just sits on top like a film.
The plaster of course will feel dry, and look OK, but when you come to put your coats on, it is sitting on top of the PVA, and your paint is not penetrating through the PVA, then your subsequents coats is sitting on top of the previous, and that is not soaking through.

But you probabaly wont get that far, as your first coat of paint will go on, when you come to do your other coats, what happens is that the first coat comes off in strips onto your roller, so now you have a messy wall, and you will have to strip all the PVA off and start again.

In some cases this hasnt happened, but it will happen even if you go back a few years later to re-decorate.

The new plaster has to breath, hence the 'Mistcoat', it allows the paint to soak into the plaster, making it ready for your subsequent coatss:D

jcaow

misgrace wrote: »

Lol TomsMom, I'm not too good at explaining either but I will try.

PVA should never on any circumstances be used on new or bare plaster.
Plasterers are the only ones who should use it when they are plastering.

When there is new /bare plaster, it needs to be sealed and penetrate through to the plaster, if you apply diluted PVA onto the new plaster it will not penetrate through, but just sits on top like a film.
The plaster of course will feel dry, and look OK, but when you come to put your coats on, it is sitting on top of the PVA, and your paint is not penetrating through the PVA, then your subsequents coats is sitting on top of the previous, and that is not soaking through.

But you probabaly wont get that far, as your first coat of paint will go on, when you come to do your other coats, what happens is that the first coat comes off in strips onto your roller, so now you have a messy wall, and you will have to strip all the PVA off and start again.

In some cases this hasnt happened, but it will happen even if you go back a few years later to re-decorate.

The new plaster has to breath, hence the 'Mistcoat', it allows the paint to soak into the plaster, making it ready for your subsequent coatss:D

Oh dear I did just PVA/water coat my newly skimmed wall (on the advice of the plasterer and I didn't check any other advice or the tin) and then I was intending to emulsion it as the rest of the walls are painted with white matt emulsion. But what are my choices now? Can I remove the PVA and start again and if so how? Or can I paint over with a paint that won't look out of place against the other walls? I'd be really grateful for your advice!!

misgrace

andrew-b wrote: »

Misgrace, i've got a painting prob for you. Before i did my first coat of watered down matt emulsion i painted over the plasterer's metal beads on the external corners with some water-based International 3in1 Primer, Sealer, Undercoat. On the tin it said it was suitable for metal and suitable for sealing new plaster too. I put the first coat on and noticed that the paint adhered thinly to the bits i'd used the primer on. I assumed it would be ok after the next coat. Anyway fast forward to today..i was putting the second coat onto one of these corners and noticed a slight ridge (as in less than a mm but visible in good light which it was today - wasn't as good when i did the first coat) where the primed plaster ended and the unprimed plaster began (higher on the unprimed side). In some places it's ok without a ridge in other places ok ..so i'm not sure if it's my painting skills or whether it's the 3in1 stuff to blame.

So what would you recommend? I'm thinking of going over the corners with some oil-based paint to take out the ridge and to give the emulsion something to adhere to...is that ok?

Andy

Andrew, you are spot on there if your talking about the beading that is showing through on your external corners, ie, round the window reveals for example, then the best way to go is to brush on slightly thinned oilbased undercoat, along the edges, leave to dry, then to be on the safe side do it again.

This will stop the metel edges from showing through your subsequent emulsion coats, the UC will stick to the beading corners, and take the emulsion no problem, cause you could be forever emulsioning just the corners, and still have a bit of the beading showing, this way, you wont.:D

misgrace

jcaow wrote: »

Oh dear I did just PVA/water coat my newly skimmed wall (on the advice of the plasterer and I didn't check any other advice or the tin) and then I was intending to emulsion it as the rest of the walls are painted with white matt emulsion. But what are my choices now? Can I remove the PVA and start again and if so how? Or can I paint over with a paint that won't look out of place against the other walls? I'd be really grateful for your advice!!

Hi, I will answer you properly later as on my way to work, speak to you later.:D

TomsMom

Good customer service there Andy so it was worthwhile contacting them. Just a shame about the wasted time and effort though. When you've got so much to do you could do without jobs going wrong and having to do them again.