Why has steam stripper blown plaster?

[SJRSJR]

About 2 years ago I had a cupboard removed in a corner and got a plasterer in to make it good. I then finished it with embossed paper and matt emulsion to match the rest of the room.

I'm now re-decorating the room and started removing the wallpaper with a steam stripper. When I got to the more recently plastered area, there was a sudden pop under the steamer head - the skim coat had cracked and has fallen away from the base coat.

I've steamed wallpaper from many a wall and never known this. Can anyone explain why it happened? It's a brick wall not plasterboard. Thanks.

 

[joe-90]

Steam strippers are too hot. Simply spray or roller water on the wall then leave it half an hour. I put my steamer in the skip years ago.

 

[SJRSJR]

I've been using it for years without a problem so I wonder what it is about this particular area. I have read that the plaster must have been blown in the first place.

 

[gregers]

you left it in 1 place for far too long.

 

[joe-90]

It's much quicker to use a roller or garden sprayer. Standing around with a stripper (ooer) is a waste of time. When you wet it with a sprayer - you go off and do other stuff.

 

[SJRSJR]

you left it in 1 place for far too long.

Maybe - not sure how long is too long but it was only matter of seconds - the paper was coming off so easily I was moving fast. I had already done half of it before anything cracked so it still doesn't explain why that particular part cracked and nothing else ever has.

I see why scoring, spraying, warm water, fairy liquid etc is less aggressive with simple papered surfaces but that's a nightmare when there are years and layers of paint to soak through - the steamer has always made lighter work of it. One wall this time had a 'skin' below the paper which was on top of a skim which was white and pasty - and all that was on top of the original plaster. The skin was dark red and stretchy. - could it be eggshell paint? The steam stripper softened it and I was able to peel it off in large strips. I can't see how water would have had much effect at all.

Anyway, thanks for the replies. I'll definitely tread carefully in future.

 

[joe-90]

Steam is a gas and has no effect on paste. The steam condenses on the wall to form hot water - which reactivates the paste. This is why water works just as well. You just need patience.