What is ‘Dew Point’?

What is ‘Dew Point’ and how does it affect painting job?

When humid air comes into contact with cooler air, or a cooler surface, the water vapor will turn into water droplets, i.e. condensation. When this occurs on a surface, it is referred to as the ‘dew point’.

When painting, it’s essential that you’re able to paint a surface without condensation forming during the application and drying stages. The optimum surface temperature for paint application is normally around 6°C above the dew point. However, some products may be more or less tolerant. If in doubt, it’s always worth checking the relevant technical datasheet.

The dew point can be calculated using the relative humidity and the air temperature. But to make life easier, you can find many dew point lookup tables on the web.