error on painting new plaster walls

[chrisdiver]

I have a problem and looking for advise on how to fix it.


I have had a conservatory built and the walls have been plastered and skimmed. I asked advise on what i should do with regards to painting as i had never painted a freshly plastered wall.


a mix of 50/50 emulsion / water was recommended.


I have done this...the second coat i just used the emulsion as it was quite watery any how...and i have now painted two more coats of my chosen colour in matt.


i allowed plaster to dry for 5 days...and painted each coat 24hrs after each other.


I noticed after my first coat of matt that there where cracks showing in the paint ( honeycombe/ criss crossing effect )..which is highlited more with with the second coat.


I have since noticed my error in that i used "silk vynil" emulsion as the original coating...but i was none the wiser, i wasnt told otherwise. and have now seen info on the net about not painting matt onto silk.


how can i fix this?


do i need to rub down my matt coats until i see the original colour and thus doing so take off the sheene of the silk vynil and paint again?


do i need to remove "all" paint back to plaster and start from scratch using matt ?


can i rub the coats down and apply PVA ( mixed correctly ) then resume painting with matt?

can the paint be washed off to help protect the plaster?


many thanks.

 

[misterhelpful]

First of all you should have allowed at least 7-10 days for just a plaster skim to dry thoroughly and 4 weeks for a full base coat and skim.

The fact that you used a vinyl silk to mist coat the walls isn't the end of the world but it's certainly not the best choice, (a non-vinyl, such as contract matt, is best) especially if you are not intending your top coats to be silk. I prefer to use around 20-25% water for mist coating but up to 50% is often used.

As you now know, matt doesn't adhere too well to silk and you should have given the silk a light sanding before applying it to provide a key.

The problem you describe is known as crazing and is generally only solved by sanding the surface as flat as possible before repainting with your matt topcoats. There is no real need to remove all the paint but you should use a pole or orbital sander to get the crazed surface as level as possible. The walls should then be bruhed down and wiped with a damp cloth to remove all traces of dust. Any deep crazing that can't be sanded out can be filled with a fine surface filler which should also be sanded, dusted off and misted, along with any bare plaster you have, before you start repainting.

If you wish, you can use an oil based undercoat before applying the matt. However, as the walls will have been well sanded, there should be no real need to do this and applying the matt alone should be fine.

DO NOT use PVA when you intend to paint - it can cause the exact same problem and a whole host of others.