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