NEW SKIMMED WALLS WHAT THE PROCEEDURE B4 PAINTING

[steveb1964]

A Mist Coat of diluted Contract Emulsion, then decorate as normal.

So there seems to be a lot of differing views over paint to water ratio when applying the mist coat ranging from 50/50 to 80/20

I'm about to do a mist coat on my plaster so what would the best ratio be? Also do you just need the one mist coat before applying your normal wall colour of 2 or 3 coats?

Thanks

 

[CHarr]

How long should a newly skimmed wall (plasterboard) be left to dry before a first dilute paint coat? I'm having a room skimmed tomorrow, and I'd like to get on and decorate as soon as I reasonably can, but I don't want to spoil the job.

 

[dcdec]

The dilution rate vary's because some paints are thicker than others.

The general rule is 25-30%, some cheapo thin paints may require less.

What a mist coat achieves is allow the dry porous plaster to soak up the liquid from the paint. The term is called satisfying the porosity. Therefore no further coats are required because you no longer have a 'thirsty' surface and you can go ahead and apply your top coats.

If you don't apply a mist coat the plaster absorbs the water from the paint which creates poor adhesion and subsequent flaking or peeling.

50/50 is a bit strong i havn't come across an emulsion thats needed that stronger dilution.

The vinyl Myth :

Its often said don't use a vinyl matt, always use a contract/non vinyl. As long as the plaster is dry its is absolutely fine to mist coat with a vinyl matt paint. The differance between vinyl and contract is breathability, vinyl will bubble if water comes to the surface and tries to escape, contract is more forgiving.

The one time i would advise using only contract matt is if the wall has been bonded, it takes much longer to dry and can appear dry on the surface when still wet underneath.
The other advantage of contract matts is price, much cheaper.

If you intend to paper :

Do not put a mist coat on because when you come to redecorate you will be left with a horrible surface from pulling the paper off. Use zinnser gardz or a glue size which is watered down flake adhesive i.e. solvite.


Ok this is aimed at none of you just the mods if they even exist on this site.

CAN WE PLEASE HAVE A STICKY ON THIS SUBJECT. PM me and i will do it or feel free to copy and paste the above or i will edit this post with more detail. Thank you.

 

[dcdec]

CHarr when the plaster has all turned from a dark to light pink colour, it becomes obvious as you see it begin to dry out.

 

[steveb1964]

The general rule is 25-30%, some cheapo thin paints may require less.

50/50 is a bit strong i havn't come across an emulsion thats needed that stronger dilution.

Is that 30% paint to 70% water or the other way around?

Thanks

 

[dcdec]

other way round mate

 

[kerry452]

Hi ive just had my flat skimmed and wondering if previous walls matter to painting.
I have a mix of old plaster, bonding, plasterboard (each are seperate walls) with new skim on top.
Will be hiring someone but want to see what the majority think and how the person will be doing it.
Thanks,
-k-

 

[Threadjacker]

About 8 years ago I coated my newly plastered bathroom walls in PVA prior to painting...I did this after being given the wrong advice on the internet.

The paint went on really nicely straight from the tub and looked great...fast forward 8 years and we extended the bathroom requiring more plastering, the old paint peeled off practically in A5 size sheets, hardly any scraping at all was needed and I was overjoyed I had used PVA.

Moral of the story is if you don't want your paint to properly adhere to the walls for whatever reason then use PVA.

Do I use it now?.....NO!