Plastering advice needed!

[ROBMP]

Hi,
I've recently had some replastering work done in my front room.
2 walls chipped back and rendered/skimmed, some patching on other walls.
When I came to paint the walls (had left apr 3 weeks to ensure that the plaster had gone off) with a mix of emulsion/water, some of the skim layer came away with the roller.
It looks like the skim layer had air gaps underneath and as soon as the roller pressed onto them, the skim just came away, this is mainly on an internal wall above a radiator but has happened on quite a few other areas also.
The other problem was with an exernal facing wall that had been rendered, there are quite a few celing to floor cracks, when you push either side of these, there is a lot of give.
Can anyone tell me what would be causing these problems, and also whats the best way to rectify them.
I've already spoken to the plasterer and he's coming round again next week to see what can be done.
Thanks

 

[joe-90]

Sounds like the plasterer has made a complete pigs ear of it.

He'll have to scrape it off and start again.



joe

 

[Third_Eye]

Dont rush to conclusions at present "ROBMP" though you have every right to be concerned. Obviously something aint right though, be patient with the plasterer. You state rendered/skimmed ! What do you mean ! Do you mean a sand & cement mix then plastered over with multi-finish ? Or do you mean another plaster method i.e. different backing coats etc ? Also you state on an internal wall above a radiator has come away, though this can happen due to that area being more porous due to artificial heat (past tence) though you also state that it is cracking from floor to cieling. It seems to me that plasterer has underestimated the suction rates of backing or render and applied the finish plaster to late or not recognized the backing required further suction killing prior to applying finish coats.

 

[ROBMP]

Hi Third Eye, thanks for your comments
Don't worry, I'm not rushing to any conclusions.
The bloke is coming back next week and I just want to get an idea as to why these problems have occured.
I'm really too sure as to what kind of render he used but I think he used a thistle multifinish.
The areas that have blistered (some above radiator but in other places too) are not cracks, some are big areas (2ft by 3ft) whereas some are smaller areas.
The cracks are on the opposite wall (external facing) and are floor to ceiling, this wall was taken back to block work and started again, funnily enough the areas where the wall was previously cracked, are fine, but the new cracks have formed where the wall was previously ok.
Do you reckon this is something he should redo at minimal cost to me? or will I be forking out for the same job twice?
On the phone he made some comment that it might be down to me applying paint to the walls before the plaster had gone off, personally I not sure about this as I left at least 3 weeks.

 

[jbonding]

it sounds like hes not done it right, is the plaster coming off in sheets or like dust? if its sheets its not adhered to the background due to failure of adhesion ie pva or keying the backing. if its dust it will be lighter in colour to the rest of the wall and that is caused by trying to bring plaster back to life after its set commonly known as fat. this happens once the plaster dries it is troweled bringing fat to the surface but it will quickly turn to dust. The other bit sounds like the background he has floated (rendered) hasnt stuck due to suction, in this case too much. Ive seen plaster painted days later so dont be fooled by this "the plaster fell off cause you painted it "

 

[Third_Eye]

How to plaster is full of unintentional contradictions, believe me. Cos i have seen plasterers plaster full rooms that have been taken back to bare brick, for the plaster to start to crack at the fireplace area and where the raiator is/was and even where the radiator is on the other room on the other side of wall ! This can be caused because of more heat being forced at these area's and causing a more highly porous area and also causing the backing coat plaster to become dried out to quickly which can result in cracking, even when no heat is on at time of plastering and after etc..........So some plasterers believe applying plaster on to brick with different preparation procedures ! Some will soak it with water, some will just dust it down and some will seal. There is no right or wrong way when plastering over bricks cos its all down intepritation and product used. So it seems to me unfortunatly the plasterer has underestimated the suction and if i done the job for u i would accept all responsibility and fix it but i would ask you kindly to buy your paint again and paint it

 

[Porker]

These pro's replying know far more than me but I've had a few mistakes when plastering in the past that sound familiar. Was the heating on in the house when he did the job? (done this - it all cracked. Turned heating off - did job 2 days later no problems.) How long did it take for the plaster to turn light pink? From my experience it sounds like excessive uncontrolled suction and possibly too much heat in the house? Blisters can also be due to too much water applied on the scratch coat to try to control suction. I've made all the mistakes in the past but I have to put them right. A pro charging the full rate should put it right for you IMO. Your painting it should have no effect particularly after 3 weeks.

 

[Third_Eye]

Good on you for admitting unforseen errors "Porker" cos we learn from each other. Also blistering can also ba caused by applying the finish coat over the backing coat to early. And blistering can also be caused by over trowelling. The list can go on forever but this is why like life plastering is impossible to be learned in say a 1 years course cos every wall/cieling etc is technically diferent, Also the the type of weather can even effect internal plastering etc etc etc.......

 

[ROBMP]

Hi - thanks for everyones comments, to answer some of the questions:

is the plaster coming off in sheets or like dust?

The plaster came off in large segments, sheets

Was the heating on in the house when he did the job?

No, I was aware of this so the heating was definately off, we had to remove two of the three radiators in the room pre plastering.

I'll see what he says when he comes back, I've got no problems with paying out for new paint etc but wouldn't want to pay for the plastering work again, previously it took two guys two days (09:00 - 16:00 then 09:00 - 14:00) and the charge came to 700 quid.
This was for various work on three walls in the lounge (one was 24 ft long), half height stairway reskim, two walls skim in upstairs bedroom.

To be honest, if he's not going to fix the lounge free of charge, then I'll probably see if I can get someone else in.
Thanks
Rob

 

[Third_Eye]

If the plasterer has any decency, he should fix it.