Mist coating new plaster. Things I have found out.

[Russell griffiths]

I’ve got a couple of newly plastered walls that are not giving me good results when painting them. 
so I did a bit of YouTube research and then phoned 3 different paint manufacturers technical help lines. 
 

the old school method has always been to mist coat new plaster with a diluted cheap emulsion paint, normally contract Matt or wickes cheap white rubbish, dilute it down slap it on everything and then away you go with your chosen top colour coat. 
 

the problems seem to be occurring with the new breed of washable scrubbable matt paints, they give good cleaning properties but you get the trendy flat Matt finish that a lot of the in vogue colour schemes call for. 
 

these new paints will not stick properly to contract Matt and need an appropriate primer used as the mist coat. 
 

somebody was having these problems a while ago but I hadn’t really looked into it then. 
 

look into better mist coating or pick your top coat first and go from there. 
 

just don’t buy some cheap white and start slapping it on. 
 

hope that helps someone. 

[Big Jimbo]

That makes sense. I like the "Trendy Matt", and they certainly are scrubbable. Cheers for the tip.

Edited February 22 by Big Jimbo

[Dobbie]

I had this problem - mist coated (with airless sprayer) using cheap contract Matt. Then applied matt scrubbable paint which is flaking and coming off in areas. 

Learning point for me - no more cheap mist coat. 

[Dobbie]

Actually, the instructions on the paint are quite specific that you must use the scrubbable paint for the mist coat.

[Dobbie]

Now planning on using zinnser guardz on the problem patches to try to sort it out. 

[Mr Punter]

Be very careful when applying the scrubbable emulsion top coat.  If you get any roller spray it will not come off once dried.

[Russell griffiths]

1 hour ago, Dobbie said:

Actually, the instructions on the paint are quite specific that you must use the scrubbable paint for the mist coat.

I think this is the problem, if you haven’t chosen your top coat the go to system on bare plaster is cheap contract Matt thinned down. 
you then buy you top coat and it says not to do that. 
 

you sort of need to know the finish and work backwards. 

[Dobbie]

1 hour ago, Mr Punter said:

Be very careful when applying the scrubbable emulsion top coat.  If you get any roller spray it will not come off once dried.

Yes, it does a grey job of staying on tiles/windows etc once dried. 

Unfortunately just not on top of contract Matt paint! 

[Dobbie]

25 minutes ago, Russell griffiths said:

I think this is the problem, if you haven’t chosen your top coat the go to system on bare plaster is cheap contract Matt thinned down. 
you then buy you top coat and it says not to do that. 
 

you sort of need to know the finish and work backwards. 

Yes. I also think it would likely be unsuitable over some of the other chalky finish coats f&b etc. 

[pritch]

The inexpensive contract Matt should not be used as a mist coat when working with scrubbable matt paints because they will not adhere properly. Start with selection of your topcoat prior to choosing any additional products. Using inexpensive paint will result in later flaking.