You can’t just take out the paintbrush inappropriately, at least not for outdoor painting. If you want to paint outside under optimal conditions, things like temperature and humidity must be taken into account. The drying time of paints and glazes is delayed at high humidity or low temperatures. In general, you should not paint outside below 10 degrees, otherwise the paint will not dry. Practice shows that in our climate the period from mid-April to mid-October is the most suitable for painting outside. A factor that is often overlooked by handymen is the dew. Rime is disastrous for outdoor painting. Therefore, do not start painting too early in the day. A car that is outside and not in the sun is a good indicator. Also take into account the ingress of dew in the evening and do not apply the last layer too late.
At what temperature can you paint outside?
First of all, the temperature. It should preferably lie between 10 and 25 degrees Celsius. Too cold is not good, but neither is too warm. That has nothing to do with the fact that people prefer to work outside at pleasant temperatures (nobody is eager to get started in freezing cold or in a heat wave), but with the drying of the paint or stain layer.
‘Halving the temperature ‘means’ doubling the drying time’
If it is too cold, it will take too long for the paint layers to dry. The lower the temperature, the longer it will take. The drying times are indicated on all Flexa and Cetabever paint and stain tins, as well as on Sikkens products, at a temperature of 23 degrees Celsius. In general, halving the temperature means a doubling of the drying time.
Special paints that can also be applied at low temperatures and high humidity
Although our temperatures are therefore unsuitable for winter outdoor painting, facilities have been brought onto the market in recent years to provide quality paintwork even in the period from November to March. But those facilities, in the form of shielding materials, heating equipment and the like, are intended more for the professional painting industry than for the average handyman. The paint manufacturers have also introduced special lacquers on the market that can be processed under low temperatures and at relatively high humidity. Ask the professional for advice in advance.
Dyeing in warm weather
Too cold is therefore not good, but painting in full sun in hot weather is also not ideal because then the stain or paint will flow and dry too quickly, causing the paint layer to become streaky.
Humidity
It goes without saying that painting in the rain is not recommended unless there is adequate shelter (on balconies or large overhangs). Humidity is much more important than a rain shower. In the morning it is usually high, which can be seen, for example, in cars that have been outside during the night. They are still wet. Wood must be dry to paint, which is usually not the case when there is still frost in the morning. However, if daytime temperatures rise to around 15 ° C, it is possible to on dry days around 10 am to paint. But condensation also forms in the evening due to the drop in temperature. And a layer of paint will not adhere and dry well on a damp surface. It is good if the paint has a certain resistance after about 10 minutes (adhesion effect) if you go over it again with a dry brush. If not, it is too cold or too damp.
The best time for outdoor painting
Smart handymen who want to take care of their house on the outside, do so best during the day (not too early, not too late) at a temperature between 10 and 25 to 30 degrees. The sun may shine, as long as it is not bright full sun.
Mid-April to mid-October
Although in our fickle Dutch climate it is never wise to simply rely on the calendar, as a do-it-yourselfer you have the best chance of suitable weather conditions for your outdoor painting between mid-April and mid-October.