How does the render bond to the Polyinsulator?
A. The render doesn’t bond to the polyinsulator; 2 coats of polypropylene are used in the mix which is a fibre. Hence after it is sprayed on the surface it acts like a grout or unibond. Once it has dried the polypropylene binds behind the wire which makes it virtually impossible to break. It is actually a positive feature that the render doesn’t bond with the polyinsulator, because this allows the polyinsulator a degree of movement hence if there was any significant movement such as an earthquake the render would not sheer off. The bonding agent that is used is also used to bond cement to cement, which is notoriously difficult to achieve.
