When it comes to painting the outside of a home or property, the weather is a massive factor that needs to be considered before even picking up a brush.
Whilst most homeowners and professionals – such as Scott Anson Painters and Decorators Ltd. – will avoid decorating outside when it is about to rain, this isn’t the only weather condition that could cause a problem. Direct sunlight, wind and the dew point should all be considered.
Temperature is another crucial factor when it comes to decorating outdoors. For more information about how temperature can affect paint, please see the embedded PDF.
Direct sunlight can pose a serious problem for exterior paint. Whilst sunny conditions might seem ideal for painting outdoors, direct sunlight can cause paint to dry too quickly.
This might sound ideal at first; however, if paint dries too quickly, it doesn’t have a chance to properly adhere to the surface. This means that the paint is at risk of flaking or falling away.
When it rains, you run the risk of a painted surface ending up less than smooth. The same can be said for dew. The dew point is the temperature where the air is sufficiently cooled to convert moisture from a vapour to a liquid, and this forms condensation on surfaces.
A higher dew point means there is more moisture in the air, and when painting you should aim for a substrate temperature that is at least three degrees above the dew point.
Like direct sunlight, wind can cause the solvents or water in paint to evaporate too quickly. If the solvents or water evaporate too quickly, the paint will not adhere properly.
Windy conditions can also result in sediment and debris being blown into fresh paint, resulting in a messy finish.
Humidity levels must be considered when choosing the best time to paint the outside of a property. Some degree of moisture in the air can help paint to dry, and this is around the 40 to 50 percent humidity range.
At this humidity level, the moisture in the air can help paint dry at a more natural rate, which will give brush marks a chance to flatten out.
If the humidity level is 70 percent or more, paint can begin to dry too slowly. Once the humidity level goes above 85 percent, the paint can thicken and become gummy. In this state, paint will not solidify.