I am looking for some advice on a problem I have with external render. The areas affected are on the plinth below the DPC on two new extensions. The render has cracked along the joints and is very friable and spalling in places as can be seen from the pictures.
The construction below damp is two skins of 4" cavity brickwork filled with concrete to 4 inches below the DPC. The foundations were built in very wet conditions but had dried out thoroughly before the render was applied. when thoroughly cured I painted the render with bitumastic paint, thinning the first coat by 50% so it soaked into the surface.
I dont know why this render is different to the original extensions which are constructed in the same way and are still really solid.
The plasterer that did the work is no cowboy and has been rendering and plastering for years and I have never had any problems with his work before. I helped him knock up and he did not scrimp with cement in the mix but I can remeber the ratios he used.
Is it possible to stabilise the surface and try and patch in or is it a case of hacking it all off and starting again? If I can avoid hacking off obviously I would prefer that as one side my new sandstone patio butts directly agains the plinth
Fozzie
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The construction below damp is two skins of 4" cavity brickwork filled with concrete to 4 inches below the DPC. The foundations were built in very wet conditions but had dried out thoroughly before the render was applied. when thoroughly cured I painted the render with bitumastic paint, thinning the first coat by 50% so it soaked into the surface.
I dont know why this render is different to the original extensions which are constructed in the same way and are still really solid.
The plasterer that did the work is no cowboy and has been rendering and plastering for years and I have never had any problems with his work before. I helped him knock up and he did not scrimp with cement in the mix but I can remeber the ratios he used.
Is it possible to stabilise the surface and try and patch in or is it a case of hacking it all off and starting again? If I can avoid hacking off obviously I would prefer that as one side my new sandstone patio butts directly agains the plinth
Fozzie
View media item 46604 View media item 46605 View media item 46606