Removing stuborn flaky paint - Zampa!?

[StumpedCanary]

When I moved in I noticed the external patio walls were spidery and asked the man who was doing other jobs for me if he could rub it down. Came home to find it in the process of being painted, wasn't happy as wanted to wait and see what happened with the walls first.
The guy who had been told to do it (by the never present foreman) said the paint was not adhering properly (it seemed clumps were coming off onto the roller), he'd almost finished and it seemed to me that the walls had not been prepared.
Anyhow a year later you may guess the majority of the new paint is flaking off and another workman has confirmed that the undercoat is chalky (wipes off on finger) and needs sealing. He bought me some stuff to do it with and I got a stiff wire brush but it seems to prefer to come off by itself and my rubbing doesn't go far unless it's already hanging off. Workman has quoted but seems reluctant to come and do it (wont confirm a date) - don't mind doing myself but is there a faster way to remove this top coat? Can I use an electric sander? (Sorry it's a lengthy explanation!). Zampa - if you're still around, I added your name as you seem to have replied to most of the related problems I've read!). Cheers everyone.

 

[Zampa]

I cant really comment to be honest..im not familiar with foreign paint and plaster...for an 'undercoat' to be 'chalky' its weird..but I really dont know anything about the stuff they use abroad

I dont think a sander will be much good though as it will probably clog

I think a few of us on here have done a bit abroad and might be better placed to help you.

 

[StumpedCanary]

Thanks Zampa, hope someone can give me direction! The paint over here seems same as at home, Dulux quality if you pay the same as you would for that. It think it's just weathered over time and needed sealing rather than having a coat of emulsion slapped on it. Hence its made some of the top coat (new paint) lift off, I'm having part of it tiled over and most of it is sound but could do with a quick solution to remove the dangly bits please!

 

[Zampa]

Try abd wash off as much of the powdery coat as possible then give the powdery areas a coat of stabilising primer first..allow to dry for a day of so then go on with the masonry paint again

 

[StumpedCanary]

okey kokey, except still concerned that have loose paint sat on top... it's all cracked but just sat around all lazy like n doing nothing - can't I encourage it off with anything - flame torch? Used one before on window sills but this paint is already crispy/flaky/thin, so don't think will have same effect. Only other option I can see is to lever it off with a scraper but will take a good while - no other faster solutions? Please????

 

[Zampa]

Definatly not a blow torch..not on plaster they could be air pockets which could blow in your face.

Its going to have to be a thin blade scraper I think and lots of El-bow (gettit?..living in Spain) grease

 

[Growler]

Would it be possible to power wash it off ...i.e ...the mess it makes. Then stabilise it.

 

[Zampa]

Yep cant any problem with that just make sure its dry first

 

[StumpedCanary]

Thanks guys, going to give the power wash a miss as no pressure hose or anything and nervous people underneath (where my balcony drains to...) may not be too happy! (Plus suspect paint flakes would dry onto tiled floor and cause another job!).
Will get a thin scraper on it over weekend and not encourage it where it seems solid, then paint over with the sealant stuff. I'll let it dry out for a few weeks before painting again.
Thank you very much for your advice and the warning about the blow torch idea - I would have given it a go!
Best wishes.

 

[Zampa]

Use a filling knife its thinner and will get behind it better.