Really need of some help with blown plaster.

[Furt0ad]

Hey all, so I kinda dabble with a bit of multifinish plastering with generally okay results. I used to work with a plasterer so understand all the basics of prep etc...

I plastered a wall at home around 6 months ago and have only just got around to painting. A couple weeks after painting I have had a couple of pretty big areas blow and crack that had no signs before hand.

Firstly I wanted to know what has caused this so I never repeat it. I'm slightly paranoid now that the rest is just going to blow but I have no idea why. I used 2 coats of pva and started to spread when the 2nd coat was tacky.

I would also like some advice on how to fix it. The majority of the wall is sound as I've gone around tapping religiously, but as I knock off the blown areas It always sounds hollow on the very edge of where it's been knocked off. NIGHTMARE! I've thought about knocking it all off and starting again but I would have to redo another wall too as it's joined with corner bead.

Would it be worth cutting around the blown areas with some type of knife or something to not disturb the rest?

If anyone can advise me with some info I would be mega grateful.

 

[Dropsalot]

Hey all, so I kinda dabble with a bit of multifinish plastering with generally okay results. I used to work with a plasterer so understand all the basics of prep etc...

I plastered a wall at home around 6 months ago and have only just got around to painting. A couple weeks after painting I have had a couple of pretty big areas blow and crack that had no signs before hand.

Firstly I wanted to know what has caused this so I never repeat it. I'm slightly paranoid now that the rest is just going to blow but I have no idea why. I used 2 coats of pva and started to spread when the 2nd coat was tacky.

I would also like some advice on how to fix it. The majority of the wall is sound as I've gone around tapping religiously, but as I knock off the blown areas It always sounds hollow on the very edge of where it's been knocked off. NIGHTMARE! I've thought about knocking it all off and starting again but I would have to redo another wall too as it's joined with corner bead.

Would it be worth cutting around the blown areas with some type of knife or something to not disturb the rest?

If anyone can advise me with some info I would be mega grateful.

Difficult to know why it's blown, spider senses tell me it must be the prep. Not trying to be clever.
You've come up with your own solution. Stanley knife a line and remove the blown plaster, keep going until you find solid plaster. Clean down, get rid of dust, apply thistlebondit or bostik green, or any other sealer containing grit. Then reskim.
Hope this helps.

 

[Beenereb4]

Plaster grits are for low suction back grounds, pva will be best.
Too many spreads saying grit all the time, it isn't needed if pva is used correctly.
I personally think the whole plastering market has been targeted with a load of unnecessary crap, tools and materials.

 

[Dropsalot]

Plaster grits are for low suction back grounds, pva will be best.
Too many spreads saying grit all the time, it isn't needed if pva is used correctly.
I personally think the whole plastering market has been targeted with a load of unnecessary crap, tools and materials.

Granted mate, the advice presumed he'd already failed on the pva route, grit left 24hrs might have made it easier for a diy-er........maybe, maybe not.

 

[Clutch & Tap]

It does sound like a adherence failure on parts of the wall.

If you wish to check the rest of the wall to see if any other parts have blown. The simplest way to do this is tap the wall with knuckles and if you get a hollow sound this indicates blown plaster.

If when tapping the wall feels solid then this means it is ok.

Hope this helps.