Approach for blisters in ceiling

[NickB_99]

curently renovating a bedroom.
Most of the artex ceilings in the house are ok, so I've not needed to cover them.
However, in the room I'm currently doing it looked like the previous house owner had gone through from loft and it been patched up and left uneven in an area.
So after applying diluted pva, I put a tight coat of Bonding on first to smooth it out a bit.
I'd left the Bonding 3-4 hrs and was probably about 25% dark at the point I skimmed. Was getting late and I needed to finish same day.
Had a few blisters even during smoothing the first coat. A few more when the 2nd coat went on.
I generally didn't do too much troweling up in those areas to not make it worse and am left now it's set with about half a dozen, in a pretty good ceiling. I'll give them a rub down and apply a little easifill if needed, which will do for me.

In the interest of improving for next time - any good ways to handle them whilst plaster still setting?

 

[roy c]

If you are using bonding you can throw a bit of cement in it and it will go off quicker for you. I have used this trick a few times, I don't know if any of the other lads do it !!!! I have never had a problem with it..

 

[NickB_99]

Thanks Roy.
I found I had plenty of working time with the Bonding, covered the ceiling and the mix was still in good shape. Will bear that in mind for future.

 

[Doggit]

Did you pva the bonding first.

 

[NickB_99]

Did you pva the bonding first.

Artex ceiling had pva applied. Tight coat of bonding put on, approx couple of mm.
no pva onto bonding.

 

[Alastairreid]

You would only need to pva the bonding if it is left to dry...to control the suction.

Skimming artex is always a gamble.

 

[Doggit]

As the plaster seems to have come away from the bonding, then it's possible that it had dried to the point where PVA would have helped. Difficult to judge here though.

 

[NickB_99]

You would only need to pva the bonding if it is left to dry...to control the suction.

Skimming artex is always a gamble.

I’d always thought the same for pva use, for suction control.
Please can you elaborate why a gamble covering artex?

As the plaster seems to have come away from the bonding, then it's possible that it had dried to the point where PVA would have helped. Difficult to judge here though.

From reading previous posts on the forum, I’d read Bonding needed to be turning dark and set after 3hrs or so.
It was at least 25% dark and approaching 4 hrs.
I’d assumed the blisters were due to either trapped air or moisture as the pressure was applied from trowel and skim.
Was curious if I had carried on trowelling them would they eventually go, or just get worse.


Interestingly this room has been split with part in an ensuite now that I’d built. I just skimmed direct with multi in there and it was fine.
The main room I had to apply bonding as very uneven from previous repaired hole. It’s only here I’ve had an issue.

 

[Doggit]

I've denibbed artex, and PVAd it then skimmed it, and it's been fine. Didn't realise that some artex might have asbestos in it in those days. In your case, I suspect if you'd have carried on troweling the plaster, you'd have caused other issues, and it's possible that that was what the blister are from, just over troweling.

 

[NickB_99]

I've denibbed artex, and PVAd it then skimmed it, and it's been fine. Didn't realise that some artex might have asbestos in it in those days. In your case, I suspect if you'd have carried on troweling the plaster, you'd have caused other issues, and it's possible that that was what the blister are from, just over troweling.

Ok, thanks.
If I need to do another room with bonding first like this, I will perhaps leave a day in between. May need a bit of pva next day, but hopefully it will behave itself better.

 

[Doggit]

May need a bit of pva next day

More likely definitely, than may. Whilst it won't be dry, it certainly won't be wet either.

 

[23vc]

Had this before, bubbles in skim when skimming over wet(ish) bonding, at the very last stage of trowelling when it’s starting to go dark brown a hard trowel will get rid of them. There’s a knack to timing it right and how hard to go with the trowel, you have to almost grind em out. Hard to explain but done it loads, was a nightmare before I realised how to sort it. It doesn’t happen if the bonding’s dried out and been pva’d

 

[stevethespreader]

Your bubbles or blisters was where the bonding was still to wet to skim as 23vc says a hard trowel will sort them but another trick is if troweling and bubbles appear you can use a sponge float to get rid of them but don't skim straight away after using it as it's still wet let it pick up a bit

 

[23vc]

Agree I’ve done that before too, forgot about the sponge float as that’s all I ever use it for

 

[stevethespreader]

Agree I’ve done that before too, forgot about the sponge float as that’s all I ever use it for

Ah sponge float and plazi is a good combo