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Help! Mist coat not adhering to new plaster!

(19 Posts)
WantToGoingTo Mon 17-Nov-14 17:20:45

If there are any painters and decorators out there, help desperately needed!

We have just had our conservatory plastered, it was not plastered before but was bare brick. They did it by putting up plasterboard and skimming over. It was finished on Thursday last week, and so has had more than 3 full days to dry which is what internet says is required fr skimming over plasterboard. It is pale pink in colour.

We bought Ronseal triple-action basecoat which says it is for sealing new plaster - water down 80:20 paint to water. My husband did that and painted one wall this morning. 4 hours later when it should be dry to do second coat, it peeled off like latex in huge foot-long pieces, leaving completely bare plaster again. You wouldn't know it had been painted!

I did some googling and figured it might be that he didn't water it down enough as it looked pretty white when he did it. So i re-did the wall. It has taken to a wall of old plaster which was adjoining, but again 4 hours later i press my finger to the wall and a whole chunk peeled away, about 3 inches big. It did not peel AS MUCH as with the earlier peeled off coat, but I think it will all peel off.

What can I do?! We need to get it sealed and painted asap in order to keep to timeline of radiators being fitted and floor being tiled. The paint was expensive and I have also heard conflicting opinions about using PVA. Any advice at all would be greatly appreciated!

To confirm, it wasn't patchy and a bit peely, but the whole paint layer peeled off in one go like latex, leaving behind the bare plaster as if unpainted.

Thanks!

PigletJohn Mon 17-Nov-14 17:28:29

do you think anyone might have put PVA glue on the wall?

Is the peeled-off paint shiny on the back, or does it have plaster dust on it?

Did the paint bubble or blister?

WantToGoingTo Mon 17-Nov-14 17:36:25

No re PVA - plasterer told us to do that but he didnt do it himself.

Not dusty, guess it sort of looks shiny? Like the inside of a latex glove?

No bubbling or blistering - just peeled off when touched. Looked fine until I touched it!

WantToGoingTo Mon 17-Nov-14 17:37:00

Thanks for any advice you can give piglet!

WantToGoingTo Mon 17-Nov-14 17:39:47

Her is pic of latest bit of prelim from me pressing finger to wall. Sorry lighting is bad no light in that room yet!

Quitelikely Mon 17-Nov-14 17:40:30

Seriously don't bother with those primers etc just buy a ten litre white paint from dulux and paint that on. The other stuff IMO isn't necessary and I've moved a lot in recent years and plastered in most of my houses.

Quitelikely Mon 17-Nov-14 17:40:56

It's around £20 from b&q

PigletJohn Mon 17-Nov-14 17:44:00

shiny might mean there is PVA on it.

wet it and rub with your finger. Is it slimy?

On a sample area, scrub it with warm water and WUL, keep sponging off the foam and slime and rinse out the sponge.

On new, uncracked, unpainted plaster I don't believe you need that Ronseal product.

if you have any ordinary emulsion paint in the house, dilute it with 20% water and brush it on. It should disappear into the surface leaving hardly any paint visible; it should not look like a coat of paint. Does it lie on the surface?

Meanwhile, see if there is a major decorator's outlet (not a DIY shed) near you. There are a couple of Zinsser products that might do the trick.

WantToGoingTo Mon 17-Nov-14 17:46:50

No PVA on it, it isn't slimy.

Hmm not sure what to do - read some suggestions about sanding it to help adhesion?

We have dulux matt pbw so we could try that watered down.

Thanks for advice.

WantToGoingTo Mon 17-Nov-14 17:48:19

Should we wait a while before we try again as plaster may now be too wet after all the painting today?

Re absorption, when painting it looks like it absorbing as it looks thin and slightly see through, but when dry it looks like it sitting on surface when it peels.

PigletJohn Mon 17-Nov-14 17:54:07

if it was plaster dust, I would expect the peeled-off film to have it stuck to the back.

If the emulsion does the trick, buy Dulux Trade Supermatt, which is non-vinyl and the preferred product for new plaster. It is not as durable as a vinyl silk, but you can easily repaint later.

The plaster should look and feel dull, not shiny. It is possible for a plasterer to polish it up like a mirror with his trowel if he has fallen out with the decorator.

If you do decide to sand it, use a very fine grade (you may find a roll of yellow sandpaper, as used on a machine) and wipe the surface lightly. It will clog with dust quickly. You don't want scratches or roughness that will show through the paint. Sponge off all dust before mist-coating.

PigletJohn Mon 17-Nov-14 17:55:52

I'm sure the pale pink plaster will be dry enough to paint unless the room is getting condensation. If the windows are wet or misty, wait until tomorrow, and air it well.

PigletJohn Mon 17-Nov-14 18:05:26

btw your picture Mon 17-Nov-14 17:39:47 looks brown, not pink. It should be the colour of an old lady's hand cream.

Take another photo of the colour with your hand against the plaster for comparison.

Plaster dries out with fresh air, not heat.

JollyTartan Mon 17-Nov-14 18:20:50

Sounds like the plasterer has polished it too much. Try sanding it down & that should help the paint sink in to plaster.
You don't need primers etc. doemulsion will do

JollyTartan Mon 17-Nov-14 18:36:50

Ignore the last bit please, was trying to delete & hit wrong button...
You don't need primers etc. Watered down emulsion does the trick for the first coat.

WantToGoingTo Mon 17-Nov-14 20:07:23

piglet it is really pale pink - the bit in the picture is dark brown I assume from the painting where it has made it look wet again.

Thank you everyone for all your advice - I have sanded a small section to test whether that helps and am also going to do a small section with watered down dulux matt white and see if either of those work before re doing the wall with whichever is successful. I really hope I don't have to sand the whole room!!

PigletJohn Mon 17-Nov-14 20:20:50

If nothing else works, Zinsser BIN or Bullseye probably will, but phone the makers for their recommendation. They are somewhat expensive. I am still puzzled. Are you sure the wall behind the plasterboard is dry?

WantToGoingTo Tue 18-Nov-14 07:50:02

Yes, wall definitely dry. I am puzzled too! I wonder if it is the too polished problem - it does feel very smooth. Will see if sanding works today smile

WantToGoingTo Tue 18-Nov-14 17:59:16

Turns out it was the paint! Tried the dulux and it has taken fine. Going to go back to the shop with the paint I bought and a carrier full of it all peeled off the wall and ask for a refund - I definitely applied it as it said on the tin!

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