Practical advice for rendering and EWI application in high temperatures.
With the UK about to bask in and enjoy the glorious sunshine, we’d just like to take the opportunity to remind you of a few considerations and additional care which must be undertaken when working within high temperatures and direct sunlight
- Please ensure all topcoat render is stored correctly and kept out of direct sunlight wherever possible. High temperatures can cause the material to effectively "bake" in the tubs, affecting its workability and final finish.
- It is important to note that material stored outside during this hot weather may be affected even if it is not used until several weeks later. Any heat damage caused during storage may not become apparent until the product is opened and applied.
- Remember that wall temperatures can be significantly higher than the ambient air temperature. On elevations exposed to direct sunlight, surface temperatures can easily be 7 to 10°C higher than the forecast temperature.
- Monitor the condition of the render throughout the day and avoid applying material on excessively hot backgrounds.
- Plan work accordingly by working on shaded elevations where possible and following the manufacturer's guidance regarding application temperatures.
- When applying contact renders or base renders, always try to work away from direct sunlight. If walls begin to dry out too quickly, they should be protected using suitable coverings, such as tarpaulins draped over the scaffold, to prevent direct sunlight from striking the surface.
- Where lime renders are being used, dampened hessian sheeting should be used to protect the work and help control the rate of drying and curing.
- Rapid drying can lead to shrinkage cracking, poor adhesion, reduced strength development and inconsistent finishes; hence additional care should be taken throughout periods of hot weather.
This Technical Bulletin guidance supersedes any advice previously given.