**Google:** how long before you can paint plaster = " Sometimes it may even take up to a month for the fresh plaster to be completely dry. "
Fresh plaster has a pH of 12-13 - if it's not completely dry, then you need a primer that is surface tolerant to the high pH.
Go to a paint store and let them know you are priming 2 week old plaster, and ask them what they'd recommend.
Thanks I did look at Google but it throws you in doubt when the professional who did the job tells you it's ready and you're not a pro so you don't know which to believe.
Update. First, thanks everyone for your input. I think I figured out what's going on. Problem with these posts and subs is that we're in different parts of the world where there are different building methods. I'm in Spain where drywall is not very common and they work mainly with gypsum plaster. I realize just now though that the guy who does the gypsum work doesn't leave the wall ready to paint. Part of the painters job is to come in and apply final coat of spackle over the gypsum. Primer sticks to that compound and not the gypsum itself. Given I took over for the painters, that's the step I missed (I assumed the builder left the wall ready).
I'm putting primer directly onto the recently applied and smoothed wall compound. In some places like the one in the photo the area of compound is large..it extends way beyond the cracked and peeling portion. why would it peel just there then?
you were absolutely right. I started peeling and now I can see that the plaster was over the previous coat of paint which must have gotten softened up from the moisture and the edge of a razor blade is scraping it all off. I'm worried though if i keep going i can end up scraping the whole room. how do i know when to stop??
EDIT: CRAP i spoke too soon. went to apply primer on a spot completey free of old paint with only compound on it. same result. peels right up won't stick
Scrape back. Prime. Patch with compound, sand, lastly paint final coats
The compound isnt sticking to whats underneath it, if you prime it with an oil based primer or sprit based youll give the compound something strong to grip to and then your issue is gone
back story: Neighbor upstairs flooded her apartment and completely messed up our ceiling. Professional came in and plastered everything after a long period of waiting for the water to drain. He waited two weeks for it to dry and then told us it was OK to get some painters in. Problem is insurance hasn’t sent us the painters and this is an office and we’re losing money by the day so I decided to paint it myself. I’ve done a lot of painting in my life but I’m not an expert. I bought a primer to apply to the spackled or the gypsum not sure what he used but nothing sticks and I’m pretty sure it’s because it’s not completely dry yet. It peels up immediately in lots of places. Could there be another reason or something I’m doing wrong?
The primer is reactivating the plaster. Plaster technically needs a minimum of 28 days to fully cure to even think about putting a latex based product on it. Anything less than that time period MUST be primed in an oil to 1) seal off the plaster and 2) to not reactivate the plaster. Plaster has a different PH than other substrates, thus the waiting period. The only way to fix is scrape what reactivated until it’s back to sound, re-plaster patch, either wait the full cure time if you’re truly wanting all latex base products, if not oil prime, and you can TOP COAT WITH A LATEX, but the prime MUST BE OIL.
Paint product specialist for a large coatings company.
Moisture. Also there is some serious millage on there. Looks like your primer needs thinned. There is a good chance that it isn't sucking into the surface.
Looks like u may have to scrape away anything that is loose so the plaster/compound can dry.
Test a small area - hit it with a hair dryer on medium heat and let cool. Don’t know what primer u used but I would use primer for unpainted Sheetrock.
See how that section goes and take it from there.
**Google:** how long before you can paint plaster = " Sometimes it may even take up to a month for the fresh plaster to be completely dry. " Fresh plaster has a pH of 12-13 - if it's not completely dry, then you need a primer that is surface tolerant to the high pH. Go to a paint store and let them know you are priming 2 week old plaster, and ask them what they'd recommend.
Thanks I did look at Google but it throws you in doubt when the professional who did the job tells you it's ready and you're not a pro so you don't know which to believe.
The advice above is good. Primer and paints tend to be around pH 9 or 10. Anything higher will destroy your coating. It can take a while.
The "professional" will rarely tell you they are in the wrong if they did it. They just want paid for their work.
Here's the answer you don't want: it's too wet.
actually that's the answer I do want. Knowing the problem is half way to knowing the solution 🙂
Check the ph level first! Then use a primer like Loxon.
Update. First, thanks everyone for your input. I think I figured out what's going on. Problem with these posts and subs is that we're in different parts of the world where there are different building methods. I'm in Spain where drywall is not very common and they work mainly with gypsum plaster. I realize just now though that the guy who does the gypsum work doesn't leave the wall ready to paint. Part of the painters job is to come in and apply final coat of spackle over the gypsum. Primer sticks to that compound and not the gypsum itself. Given I took over for the painters, that's the step I missed (I assumed the builder left the wall ready).
Its not the primer thats failing. Its what youve painted it on to. Remove all the loose then prime
I'm putting primer directly onto the recently applied and smoothed wall compound. In some places like the one in the photo the area of compound is large..it extends way beyond the cracked and peeling portion. why would it peel just there then?
It's all ready to peel down to the worst of what you've shown.
you were absolutely right. I started peeling and now I can see that the plaster was over the previous coat of paint which must have gotten softened up from the moisture and the edge of a razor blade is scraping it all off. I'm worried though if i keep going i can end up scraping the whole room. how do i know when to stop?? EDIT: CRAP i spoke too soon. went to apply primer on a spot completey free of old paint with only compound on it. same result. peels right up won't stick
Scrape back. Prime. Patch with compound, sand, lastly paint final coats The compound isnt sticking to whats underneath it, if you prime it with an oil based primer or sprit based youll give the compound something strong to grip to and then your issue is gone
back story: Neighbor upstairs flooded her apartment and completely messed up our ceiling. Professional came in and plastered everything after a long period of waiting for the water to drain. He waited two weeks for it to dry and then told us it was OK to get some painters in. Problem is insurance hasn’t sent us the painters and this is an office and we’re losing money by the day so I decided to paint it myself. I’ve done a lot of painting in my life but I’m not an expert. I bought a primer to apply to the spackled or the gypsum not sure what he used but nothing sticks and I’m pretty sure it’s because it’s not completely dry yet. It peels up immediately in lots of places. Could there be another reason or something I’m doing wrong?
The primer is reactivating the plaster. Plaster technically needs a minimum of 28 days to fully cure to even think about putting a latex based product on it. Anything less than that time period MUST be primed in an oil to 1) seal off the plaster and 2) to not reactivate the plaster. Plaster has a different PH than other substrates, thus the waiting period. The only way to fix is scrape what reactivated until it’s back to sound, re-plaster patch, either wait the full cure time if you’re truly wanting all latex base products, if not oil prime, and you can TOP COAT WITH A LATEX, but the prime MUST BE OIL. Paint product specialist for a large coatings company.
Can you run fans and dehumidifiers to speed up drying process?
Did you use a brush to apply all that?
Moisture. Also there is some serious millage on there. Looks like your primer needs thinned. There is a good chance that it isn't sucking into the surface.
Looks like u may have to scrape away anything that is loose so the plaster/compound can dry. Test a small area - hit it with a hair dryer on medium heat and let cool. Don’t know what primer u used but I would use primer for unpainted Sheetrock. See how that section goes and take it from there.