PVA bonding – repairing a badly rendered wall.
The garden wall on my house was very badly rendered. The rendering is either flaky or falling off. I need to get it re-rendered and want to ensure that it is done properly. Some of it was repaired by the builder at the snagging stage using a white mix (I do not know what was used) but this was put straight on the flaky wall without any preparation and has now fallen off. This time I want to make sure that it is done properly using a PVA bonding agent before rendering which would seal the surface and increase the adhesion of the new render.
Generally this PVA costs about £10 for a 5 litre container in the UK. I do not know what they call this in Spain but I had difficulty explaining what I wanted when I went to the builder’s merchants. Can anyone give me some information on what this is called in Spain and where I may be able to buy it at sensible prices?
On a separate issue, can anyone advise on the sand and cement mix for the rendering as this seems to be part of the original problem. I think that the builder may have used the same cement mix for the bricklaying and the rendering. The current rendering looks very rough and coarse. I am aware that sharp sand should be used for the render in the UK and wonder what seems to happen in Spain.
Thank you for any information, help and advice.
PaddyW