Bathroom ceiling - paint mud cracking/crazing

[CalumH]

Hi folks,

Having a problem with the paint on my newly plastered ceiling mud cracking. Looking for some advice, is there a fix or do i need to sand down and start again. This is what has been done so far:

1. I had the bathroom ceiling re-plastered.
2. Applied a moisture stop:

http://www.valtti.co.uk/paint-range/ranges/professional/products/luja-moisture-stop/

3. Applied a universal primer:

http://www.valtti.co.uk/paint-range/ranges/professional/products/luja-universal-primer/

4. Applied a finishing paint:

http://www.valtti.co.uk/paint-range/ranges/professional/products/luja-finishing-paint/

This is a bathroom ceiling so what ever I put on the ceiling must be able to deal with moisture.

So does anyone know why the paint is mud cracking and how can I fix it?

Thanks in advance for any help!

Calum

 

[joe-90]

You don't need all those products.

All you need is cheap contract emulsion watered down by 25%.

The crazing means your paint is too thick.

Then a finish of your choice satin acrylic (bathroom paint). Any old type will do.

 

[CalumH]

Thanks for that!

 

[joe-90]

Can you post a picture to save us guessing?

 

[CalumH]

Untitled

• CalumH
• 18 May 2012
• 1

 

[CalumH]

I still have some of the above paints left are any of them suitable for sorting this out? Is it just a case of thinning them?

I did try and put another coat on the interior paint on but the cracks just came through within a couple of days.

 

[emilybronte]

No, if you apply thinnned down paint to that surface, you'll be no better off. Subsequent layers of paint will probably still peel off/craze.

You need to sand the whole affected area back to bare plaster so you have a smooth surface on which to apply your mist coat, as advised above.

Alternatively if it has been mist coated originally, sand off all the cracked paint and apply Zinsser Gardz to affected areas (twice) before procceeding to paint with chosen finish (eggshell or whatever).

 

[CalumH]

Thanks Emily.

Thats not what I wanted to hear but if thats the only way to do it then I better get sanding!

 

[CalumH]

What is the easiest way to sand off the paint eg. belt sander?

It has 4 coats on so don't think it would be possible to do it by hand?

Once sanded back can I use any of the above paints, once thinned? I needs to be moisture proof as it is right above the shower.

Thanks!

 

[emilybronte]

What is the easiest way to sand off the paint eg. belt sander?

It has 4 coats on so don't think it would be possible to do it by hand?

I would use a palm sander, but you can do it by hand with a sanding block. Not a belt sander - they aren't designed for walls, really. What sort of area are you talking about?

Once sanded back can I use any of the above paints, once thinned? I needs to be moisture proof as it is right above the shower.

Thanks!

I don't recognise your finishing paint, so I can't comment on it.

I would go for a good quality eggshell finish.

 

[frustin]

i took mine back to plaster and then applied watered down followed by bathroom paint from b&q, it still cracked back to the plaster. i was then told that a watered down with pva glue mix would be good. i moved house before trying it though.

 

[emilybronte]

No! Avoid using PVA. It might work for the first coat of paint, but subsequent coats may peel off.

 

[frustin]

i probably didnt water it down enough. how many watered down layers? is it like applying to fresh plaster board then?

 

[CalumH]

Hi folks,

OK I got a palm sander and tried to sand the paint back to the plaster but it just doesn't seem to get through this stuff and there is about 6sq/m to get through.

Any ideas of how to remove or paint over?

 

[frustin]

i was able to peal most of it by hand and that which i couldn't, i sanded as best i could and painted over.