We do not advise rendering over existing renders, site batched renders or other manufactured systems as there are too many unknown anomalies that would prevent an informed judgement. Specifically, these relate to the condition of the existing render in regard to its strength, thickness, quality and existing applied surface treatments to provide recommendation to support the additional extra weight from a new render.
For this reason, we would therefore be unable to predict the lifespan of a further render coat and its potential for cracking or debonding.
In addition, and more significantly, rendering onto painted surfaces is not in-keeping with good building practice. In this instance, delamination, crazing and cracking are highly likely outcomes in this scenario.
There are three solutions available in this instance, with a further coat of render being the only solution if deemed paramount. However, we will not guarantee a system that has been applied over existing rendered surfaces, other than an identified, virgin, existing Weber render after a detailed inspection has been carried out by a member of our specification team.