PVA

[Fallingup]

I intend sealing a freshly plastered wall with PVA prior to painting. However I seem to remember someone saying that was a no-no and that it should be sealed using mist paint coats. PVA seems much less hassle. Can anyone advise.

[V8RX7]

PVA is a bad idea - you want to let water out.

Mist coat is what everyone has used for 20+ years and takes as long as PVA

[Dogwatch]

You must allow the plaster to dry out.

[Fallingup]

V8RX7 said:

PVA is a bad idea - you want to let water out.

Mist coat is what everyone has used for 20+ years and takes as long as PVA

But the plaster will be dry

[Gav147]

Don't use PVA, as above use a watered down coat of emulsion.

PVA - the single most miss used material in the building industry!

[dickymint]

Mist coat is the traditional way. For speed a coat of SBR will do the job nicely. Do not use PVA as you think it's dry but will revert back to a sticky gunk if in contact with moisture.

[Fallingup]

dickymint said:

Mist coat is the traditional way. For speed a coat of SBR will do the job nicely. Do not use PVA as you think it's dry but will revert back to a sticky gunk if in contact with moisture.

SBR?

[V8RX7]

I you seal a wall - ie with tiles - or to a lesser extent PVA / SBR when you have a warm room and colder walls you get condensation - which isn't great.

With normal construction the water gets absorbed and released.

It's why we don't build out of plastic

[Fallingup]

V8RX7 said:

I you seal a wall - ie with tiles - or to a lesser extent PVA / SBR when you have a warm room and colder walls you get condensation - which isn't great.

With normal construction the water gets absorbed and released.

It's why we don't build out of plastic

But doesn't paint seal the wall as well? I'm not trying to argue. I just don't quite understand.

[V8RX7]

Fallingup said:

But doesn't paint seal the wall as well? I'm not trying to argue. I just don't quite understand.

Not normal matt - which is all I ever use.

But yes vinyl works in a similar way - which is why it can cause problems when you redecorate

[227bhp]

If the wall is 100% dry then use PVA, just make sure you mix it to the correct ratio. These things get a bad name because people misuse them like getting the ratio wrong or using the internal type outside etc.

[B17NNS]

Fallingup said:

Can anyone advise.

Yes. Don't do it. PVA is not for decorating (nor is it for tiling).

Fresh plaster needs a mist coat - watered down contract (not vinyl) matt emulsion. Followed by two coats of your chosen finish.

Alternatively you can use this instead of a mist...

https://www.screwfix.com/p/no-nonsense-trade-bare-...

Edited by B17NNS on Sunday 16th December 13:08

[dickymint]

227bhp said:

If the wall is 100% dry then use PVA, just make sure you mix it to the correct ratio. These things get a bad name because people misuse them like getting the ratio wrong or using the internal type outside etc.

If there is any chance of moisture getting to PVA it will absorb it and return to sludge. SBR won’t and works well.

[Gooose]

Screwfix Bare plaster paint in the dogs dangles! Sack all the mist coat off!

[Fallingup]

Gooose said:

Screwfix Bare plaster paint in the dogs dangles! Sack all the mist coat off!

You're The Man. Thank you.

[allegro]

Another vote for the bare plaster paint! read all the threads about pva, mist coats etc but gave the plaster paint a go and was hugely impressed.

[thebraketester]

I just used wickes paint for new plaster to paint about 100sqrm of new plaster and it worked perfectly.

[dhutch]

Not used bare plaster paint, but how is doing a mist coat hassle?

Slop some matt white in the roller tray with a slug of water and whack a coat of that round everything first.

By the time you've done the walls you can get the second full strength coat on the ceiling leaving just the finish coat on the walls. All be done before lunchtime if you start after breakfast!


Daniel

[Flibble]

Gooose said:

Screwfix Bare plaster paint in the dogs dangles! Sack all the mist coat off!

I used it after having a room skimmed, worked a treat.

[Alucidnation]

Our decorator used the bare plaster paint on a rental of ours after it was refurbished, and while having brilliant opacity, it did not stick all that well to bare plaster.

He said they would go back to misting.