Expert Advice on Render Application in Winter

Wetherby Technical Director, Joe Ragdale offers valuable advice on the application of Wetherby’s render products & systems in the Winter months.

The wet and cold weather conditions we’re likely to sustain throughout the winter months can create many problems for rendering. Products and systems must be applied in the correct conditions and protected adequately to prevent system failures during this difficult period. I want to make you aware of the best working practices during these months to reduce the risk of wash-offs and product failures.

When can you render?

Application of all polymer modified renders, adhesives, primers and silicone products can only occur when the temperature is 3°C and over 5°C for a significant part of the day, with no frost forecasted.

Wetherby products are water-based and therefore dry through physical evaporation; cold temperatures significantly slow this process down and in turn dramatically extend drying times. Weather forecasts must be consulted before application to ensure the render has a reasonable period of time in adequate temperatures to allow the product to cure.

Humidity levels are another factor that should be taken into consideration when applying WBS products.
Wetherby renders will only cure in relative humidity of less than 90%. Higher humidity levels of over 90% will prevent the products from curing. Again, applying products in high humidity will lead to the render remaining wet on the wall for extended periods making it susceptible to frost damage and wash-offs.

What renders work best in cold weather?

I trust this is useful information and will help to ensure damage to the WBS render systems in winter conditions is kept to a minimum. If you would like any help or advice, our Technical team will be happy to help you.