Peeling paint internal wall. Maybe latex paint? Can I seal this?

[Jpol]

The previous owner of our house must have painted the wall in some sort of semi gloss latex paint. When scuffed in the move we noticed it’s easy to scrape off.
Not sure what to do as scraping a hall to landing floor is a big job. Do you think I could prime this with something?

 

[Wayners]

Old chalky paint under the modern emulsion?
Rub with a damp sponge to see if the old chalky paint comes off.

That will be the problem

 

[Jpol]

thanks for your reply. I think it is.. what do I do?

 

[Jpol]

Old chalky paint under the modern emulsion?
Rub with a damp sponge to see if the old chalky paint comes off.

That will be the problem

Thanks for your reply. I think it seems like it is chalky based on your advice. What do I need to do?

 

[Wayners]

Remove the paint.
Wash walls.
Emulsion walls with a suitable paint.
You may have lime plaster so you need emulsion that is suitable for lime plaster.

Problem is you may struggle to remove all that paint.
Might be easier for now to wash that problem area back to the original plaster then emulsion again.

There are lots of houses with lime plaster that have the wrong emulsion on and don't have a problem.
You can prime chalky paints with products like Gardz. Then paint with a quality emulsion, even one with vinyl in.

 

[Leftum]

@Wayners @opps
I’ve painted a few houses with newly plastered walls. I’ve always primed them with diluted trade white to prime and then used a better paint to finish.

On the walls in my pics I have done the above but used McPherson durable acrylic Matt this time. I noticed a blister and then on closer inspection noticed it’s all coming away from the wall. I’ve scraped most of it off now. It’s only stuck to about 10% of the walls.

My questions, is acrylic not suitable or is the drying time longer ? It had been about 30 hours when I noticed it was an issue.

Should I prime with diluted acrylic or a special primer now ?

Thanks in advance.

 

[Wayners]

It's not a good to prime walls with trade matt as its very dry. Durable paints have resins in that don't like dry surfaces so follow the manufacturers application spec.
They can bubble and react with contract matt.

I used tinted acrylic primer undercoat with a splash of water or Gardz over plaster. Then the quality emulsion.

The manufacturers say to use the paint with 10% water on first coat but I never liked to do that. I think gardz is best but the paint recoat times can be 4 to 6 hours. Summer fan can cut that time.

 

[Leftum]

It's not a good to prime walls with trade matt as its very dry. Durable paints have resins in that don't like dry surfaces so follow the manufacturers application spec.

That makes sense, thank you.

I’ve used Gardz on plasterboard and paint stuck like **** to a blanket. I think I’ve been to cheap with my prep.

 

[opps]

As per @Wayners ' post. Contract matt emulsions are designed for damp plaster that hasn't fully dried yet. They contain very little latex/acrylic and allow any residual moisture to escape. They are not suitable as primers for regular emulsion.

The mist coat is supposed to reduce the level of "suction" in the plaster so that the regular emulsion can cure without the water in the paint being sucked into the plaster.

Waterbased paints cure through a process called coalescence . As the water evaporates off, the molecules bond down. Too much suction and much of the water gets sucked into the wall, messing up the coalescence.

Contract emulsions do very little to reduce the suction.

Personally, I just stick with the instructions on the side of the tin with regards to thinning regular emulsion for the mist coat.

Other than contract emulsions being a no-no, over thinning regular emulsion mistcoats paints is a no-no. Unfortunately, there are many people on the likes of youtube that recommend a 50/50 ratio. The worrying thing is that many of them are fellow professional decorators.

Other places that I have seen contract paint used in appropriately- I was working in a newly refurbed property. I was painting custom built furniture. The contractor noticed that the first time they tested the shower, the white ceiling quickly became dark (until the moisture had evaporated). It was obvious that the decorator used contract emulsion. I applied acrylic primer over the contract matt and then applied a couple of coats of waterbased eggshell.

There is a reason why contract matt is so cheap- it is an inferior product.

Sorry- this is not intended to be a lecture. I am mindful of the fact that a newbie might, further down the line, need to understand how emulsions work.

 

[Jpol]

Does anyone have any advice for my original post at the top please
Do I need to use paint stripper do you think?
@opps @Wayners

 

[opps]

Does anyone have any advice for my original post at the top please
Do I need to use paint stripper do you think?
@opps @Wayners

Sorry, got distracted.

@Wayners ' advice regarding Guardz should (hopefully) be fine.

I would be inclined to sand/scrape away the paint, but I have expensive sanders and lovely Olfa scrapers... And, ultimately, I get to charge the customer, so I am not out of pocket. Oh, and that isn't me trying to overcharge, I don't want a customer phoning me and complaining about paint failing the "fingernail test".

 

[Leftum]

As per @Wayners ' post. Contract matt emulsions are designed for damp plaster that hasn't fully dried yet. They contain very little latex/acrylic and allow any residual moisture to escape. They are not suitable as primers for regular emulsion.

The mist coat is supposed to reduce the level of "suction" in the plaster so that the regular emulsion can cure without the water in the paint being sucked into the plaster.

Waterbased paints cure through a process called coalescence . As the water evaporates off, the molecules bond down. Too much suction and much of the water gets sucked into the wall, messing up the coalescence.

Contract emulsions do very little to reduce the suction.

Personally, I just stick with the instructions on the side of the tin with regards to thinning regular emulsion for the mist coat.

Other than contract emulsions being a no-no, over thinning regular emulsion mistcoats paints is a no-no. Unfortunately, there are many people on the likes of youtube that recommend a 50/50 ratio. The worrying thing is that many of them are fellow professional decorators.

Other places that I have seen contract paint used in appropriately- I was working in a newly refurbed property. I was painting custom built furniture. The contractor noticed that the first time they tested the shower, the white ceiling quickly became dark (until the moisture had evaporated). It was obvious that the decorator used contract emulsion. I applied acrylic primer over the contract matt and then applied a couple of coats of waterbased eggshell.

There is a reason why contract matt is so cheap- it is an inferior product.

Sorry- this is not intended to be a lecture. I am mindful of the fact that a newbie might, further down the line, need to understand how emulsions work.

No I appreciate the detailed response a lot, thank you.

I’ve always painted with leyland trade and I don’t think I’ve used an acrylic durable paint before. It’s definitely given me a lot to think about on going.

I’ve scraped most of the paint off now, sanded and primed with acrylic primer. I’ll do a little test bit this time, just to be sure as I don’t want the agro and wasted time again. But to be honest the primer seems to be a lot better than the mist coats I’ve done in the past.

Thanks again. I’ve learnt a lesson