Repairs to rendered external wall not looking good

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#1
I hope I have come to the right place but I could do with some helpful advice
Back in June on one of the hottest days of the year my Daughter got a plasterer to came to patch up a few areas on her 1929 renderer property around the tops of Windows and doors where lintels have been put in and pvc windows and doors fitted . At first the repairs looked good and were well matched with the surrounding render. We were going to paint the walls but bits of the render stared to come away and we found then if you rub it just turns to dust. We asked the plasterer to come back and after many calls and three months he came back repaired the few areas where the plaster had dropped out blaming the fact that they were using the doors and window?? and then painted it with a water seal liquid. He then argued that it was absolutely fine and we should paint it reassuring my Daughter that he had done another like it at the same time and it had now been painted and it was fine. Because my Daughter is now 9 months pregnant I have taken up the cause. Should I expect the render to crumble to a dust way under my thumb when lightly rubbed. I wondered if there is a problem due to it being done in the severe heat and the renderer does not want to put it right. I would really appreciate any help and guidance you could give. Thank you
 

Stevieo

Well-Known Member
#3
I hope I have come to the right place but I could do with some helpful advice
Back in June on one of the hottest days of the year my Daughter got a plasterer to came to patch up a few areas on her 1929 renderer property around the tops of Windows and doors where lintels have been put in and pvc windows and doors fitted . At first the repairs looked good and were well matched with the surrounding render. We were going to paint the walls but bits of the render stared to come away and we found then if you rub it just turns to dust. We asked the plasterer to come back and after many calls and three months he came back repaired the few areas where the plaster had dropped out blaming the fact that they were using the doors and window?? and then painted it with a water seal liquid. He then argued that it was absolutely fine and we should paint it reassuring my Daughter that he had done another like it at the same time and it had now been painted and it was fine. Because my Daughter is now 9 months pregnant I have taken up the cause. Should I expect the render to crumble to a dust way under my thumb when lightly rubbed. I wondered if there is a problem due to it being done in the severe heat and the renderer does not want to put it right. I would really appreciate any help and guidance you could give. Thank you
My gear went like that once. It was because we used washing up liquid as plasticiser in cement and my helping hand fella chucked in half a bottle of the stuff instead of just a dash.

I've never overdone it like that with proper waterproofer/plasticiser maybe someone who works with s/c more might've seen it?
 

Simon85

Well-Known Member
#4
Not enough cement in mix or , far too much mortar mix,possibly mixed to long and goes fluffy, which weakens the mix. Sun can dry it out to quick so once set near need to soak it again to stop it dry in out too quick and turning dusty.
 
#5
As stated above, if sand and cement render cracks up fairly early it’s usually too much cement in the mix. If it crumbles and rubs away usually too much sand.

What I will tell you though is if you have had concrete lintels put in, nothing will stick to them properly without the correct preparation.

An incorrect sand and cement mix with incorrect substrate preparation.
 

essexandy

Private Member
#6
My guess, and it can only be a guess, is that there was absolutely nothing wrong with the mix ratios or the application. It just dried to quickly in the high temperatures and if it had been kept hydrated for a few days after application all would have been fine. The plasterer should have advised that at the time.
 
#8
im thinking they have overlapped onto the existing and feathered in rather than cut out neat lines and render into them.
if feathered in the render is too thin on the overlapp which will cause it being able to rub away.

but i have to say i could be wrong without seeing the work
 

Vincey

Private Member
#9
Will he come back ?
Tbf id always go back to any job with a problem even if it takes a few weeks to get there I will
 
#11
Thank you very much for your helpful replies.
I will get an image tomorrow and upload it. The plasterer who did the job insists its good to paint and doesn't agree that there is anything wrong. I thought he was going to take it back off and render it again but instead he painted it with a water seal. Would you agree that the areas need to be rendered again or should I attempt to paint it? I just want the job done right so would be prepared to get some one else in to do a proper job.
 

essexandy

Private Member
#12
Thank you very much for your helpful replies.
I will get an image tomorrow and upload it. The plasterer who did the job insists its good to paint and doesn't agree that there is anything wrong. I thought he was going to take it back off and render it again but instead he painted it with a water seal. Would you agree that the areas need to be rendered again or should I attempt to paint it? I just want the job done right so would be prepared to get some one else in to do a proper job.
If he managed to get a masonry stabiliser to soak right into the mortar then it may well be fine to paint.
 
#13
The image shows what happens to the render with light rubbing of my thumb. The plasterer used b and Q water sealer not Stabiliser. I can use stabiliser if it would work . Just don't want to waste time and money painting it if no use.
Thank you
 

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Stevieo

Well-Known Member
#15
The image shows what happens to the render with light rubbing of my thumb. The plasterer used b and Q water sealer not Stabiliser. I can use stabiliser if it would work . Just don't want to waste time and money painting it if no use.
Thank you
What do you mean 'you can'?

At the end of the day, whatever way up you turn it, freshly(ish) applied plaster shouldn't rub off like that, so he needs to come and sort it out.
 

essexandy

Private Member
#16
A Tyrolean effect will be even more prone to rapid drying out resulting in a powdery surface than a plain faced render. There's just so much surface area (open texture). It needed to be kept hydrated for the cement to cure.
Well that's what it looks like to me.
 

Rigsby

Private Member
#17
It has dried to fast. Rapid hydration.

Rapid drying causes the water to evaporate before it chemically sets so will never cure hard. Also the chances are he has gone tight up to your frames. The frames expand in the sun causing cracking.

A lot of Joe Public insist on having their rendering done in summer. But in a heat wave that will be worse that in January. At least in January you can use a frost proofer. And it will work.

But when a customer wants it doing and we have a prolonged heat wave who may believe the nice got weather is in their favour then maybe the customer can take the blame. Those same customers who want and insist on summer work are the very one's who will not entertain cement work after September.

Apparently it's too late in the year?

What do they know!
 
#18
It has dried to fast. Rapid hydration.

Rapid drying causes the water to evaporate before it chemically sets so will never cure hard. Also the chances are he has gone tight up to your frames. The frames expand in the sun causing cracking.

A lot of Joe Public insist on having their rendering done in summer. But in a heat wave that will be worse that in January. At least in January you can use a frost proofer. And it will work.

But when a customer wants it doing and we have a prolonged heat wave who may believe the nice got weather is in their favour then maybe the customer can take the blame. Those same customers who want and insist on summer work are the very one's who will not entertain cement work after September.

Apparently it's too late in the year?

What do they know!
It was a lovely summer but you had to take extra precautions if you were rendering. After curing you almost needed to spray it with water each day or more realistically get the customer to. Old school methods still the best in these circumstances.
 

essexandy

Private Member
#19
On site I would hose down the first coat for at least three days during the summer months but tell the foreman that it was his responsibility to look after the topcoat once I'd finished. 9 times out of 10 it'd never get a drink before being painted.
 

Rigsby

Private Member
#20
If you use a waterproofer then watering down will do zilch. The water proofer repels the water.

If you don't use it and you have created an absorbent mix then yes if done daily. The first 3 days are important.

But some customers can't be bothered to water it down. As one customer told me once, ’didn’t have the time, sorry!’. ’It’s guaranteed anyway!’.

If I can't cover it up to retain its water then I give it a miss.
 

essexandy

Private Member
#21
If you use a waterproofer then watering down will do zilch. The water proofer repels the water.

If you don't use it and you have created an absorbent mix then yes if done daily. The first 3 days are important.

But some customers can't be bothered to water it down. As one customer told me once, ’didn’t have the time, sorry!’. ’It’s guaranteed anyway!’.

If I can't cover it up to retain its water then I give it a miss.
I always use waterproofer but the render will still take in enough water for the first few days for it to cure nicely. Everbuild 3in1 is my preferred waterproofer nowadays.
 
#22
I always use waterproofer but the render will still take in enough water for the first few days for it to cure nicely. Everbuild 3in1 is my preferred waterproofer nowadays.
I would use a waterproofer in the scratch coat which as Andy says would allow the top coat a drink. I don't have a preference but had good results with freeflo.
 

Vincey

Private Member
#24
Am I wrong in saying to be posting a kind of complaint about a picture with a bit of gear the size of a finger nail is a problem?
When the general public post pictures of “a issue “ they always are of a tiny mm or 2 of a scratch or a mark or bit , tbh starting to think it’s a bit ridiculous tbh
 
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