Mist coat strength question

[jackjack04]

Hi chaps

1week ago i mist coated the newly plastered bedroom walls and ceiling with 50/50 dulux matt paint, but have ran into a problem.

I used adhesive to fix skirting and the next day with a few knocks they fell off the walls taking the mist coat with them. I then decided to test the strength of the mist coated walls with gaffer tape. This tape easily pulls the mist coat off (from around knee to head height). A good scrape with a wallpaper scraper also flakes off the paint.

Just wondering what is normal, in terms of strength of a mist coat and any ideas on what my next action should be. I have already started to scrape back the paint to fresh plaster.

Cheers in advance

Jack

 

[KenGMac]

jackjack04, good evening.

The 50 / 50 is the industry norm?

Question? was the new Skim very, very "highly polished" ?

Ken

 

[jackjack04]

Hi ken

It was shiny, I could look down it and see reflections, it felt very smooth. But to be fair it's the first time I've ever had a room plastered, so have nothing to compare it to.

I realise gaffer tape is strong and is more likely than masking tape to pull it off, but the paint is coming off very easily in parts.

Cheers for the fast reply

 

[cwhaley]

Skirting needs to be fixed on properly (mechanical fixings) rather than glues and stickies.

 

[JP_]

I use Delux Matt for mist coating, only needs to be watered down 1 in 5, which makes it less messy. Not had a problem yet.
I always leave an unpainted gap for the skirting too - mostly to avoid hitting the floor with the roller and picking up dirt.

 

[jackjack04]

Cheers, the skirts have been screwed .

What are your suggestions for the mist coat that flakes easily when gaffer tape is placed on it?

Regards

Jack

 

[JP_]

don't put gaffer tape on it!

 

[jackjack04]

I don't normally put gaffer tape on it.

Just a bit worried that as the tape is pulling it off easily, does that mean that the adhesion is poor and that it will peel in the future?

 

[sparkwright]

I'm not sure if using gaffer tape to see if the paint comes off is actually a sure way to say that the paint has adhered correctly.

Maybe a scrape test in a discreet location.

Or see what happens when more coats are applied (try a small wall first). If you can see the paint begins to bubble or lift, then it's failed.

Just be careful not to mess up your work, as you may be worrying over nothing.

I gather you can now buy mist coat already mixed, which could reassuring in the future.

 

[KenGMac]

jackjack04Good evening again.

Sorry in delay in replying, been busy elsewhere?

Rational behind my post was that is the skim was very, very highly "polished" that can at times throw the paint off?

As sparkwright above would appear to be a good way to go?

Ken

 

[jackjack04]

Evening chaps

Thanks for the replies again.

Ive actually now scraped all the walls back to clean plaster. I'm going to very lightly sand to remove the rest of paint on the walls, then get it wiped, hoovered, etc to remove all dust.

I will then try the plaster paint in patches that I know had poor adhesion. Probably about 30% of wall paint came off easily the rest needed to be worked at.

Regards the ceiling, it had mist coat plus 1 full topcoat. I did as sparkwright suggested and scraped back the patches that came off. Approximately 10% of ceiling came away easily and scraped to a hard edge taking about 40% of ceiling with it.

I'm starting to think about reasons why this may have occurred. I think over polished plaster maybe a slight factor but believe it's more than likely the cool temperature in the room. We have no radiators at the moment (they are being fitted tomorrow), so I think possibly because it was cold the moisture in the mist coat sunk into the plaster keeping the plaster wet for a long time, but the paint on top dried.

I'm just guessing but the day after I painted the mist coat I came home from nights to find the windows full of condensation, makes me think temperatures and lack of ventilation maybe the route cause! But we will find out soon!

Cheers!!