News19th August 2019
The Great British Summer - Can I paint in cooler, damper weather?
Exterior painting in damp weather. If you are suffering at the hands of the current unpredicatable UK climate, you'll be thrilled to learn about our High Build Multi-Surface Paint in White & Pastel Shades, A1040. It will tolerate a light shower of rain for about 30-40 minutes, can be applied over render that’s only 6 weeks old and in temperatures down to 8C in dry conditions.
Suitable for application to cement rendering, concrete, brickwork, Aqua Board, wooden or cementitious Soffit boards, plus a broad spectrum of other surfaces such as powder coating, previously painted metal, metal cladding and timber surfaces when used with a suitable primer. It can also be used as a floor finish in low traffic situations. Available in a fine or medium Anti-Slip finish for floors. It comes in BS4800 & RAL Pastel Colours with Darker Colours to order. Minimum lead times and minimum quantities apply. Please call our Technical Team for full advice: 01202 295570.
Painting in cooler weather.
If you are considering applying paint or other coatings during a period of cold or cooler temperatures, you should take all precautions to ensure your selected product does not fail. Failure will be caused by application at a temperature determined to be outside the optimum range (in this case “too cool”) by the manufacturer as set out in the associated Technical Data Sheet.
Several factors must be considered when applying paints and coatings in cooler, damper conditions.
Substrate (the surface to be painted) temperature:
In cooler months, application in direct sunlight is the best practice to adopt as this will help increase surface temperatures up into the “safe” range (15 C +) even when air temperatures are cooler. In general, paints should be applied only when both surface and air temperatures are above 5 - 10 C and primers should only be applied when temperatures are above 10 C in order that they dry properly.
In Winter, floors and metal surfaces will generally be several degrees colder than the air temperature and this should be factored in to timescales and budgets; where practical, heating systems should be considered to raise temperatures in the subject environment.
The paint or coating:
As temperatures drop, so the viscosity (the property of a fluid that offers resistance to flow) of the coating will increase. This change in the paint will hinder the flow of the coating during application. Often, a small drop of thinners may help but it is recommended that before use, the paint is stored in a warm place (such as an airing cupboard or boiler room) or perhaps warmed very gently in warm water in a bath or bucket. If thinners are used, it should be noted that this action will reduce the solids content of the paint leading to a less durable and predictable coating. Water-borne coatings must not be allowed to freeze during transportation or storage as they will be damaged and become unstable; the effects of the freezing process are irreversible and the paint must be disposed of without use.
Relative humidity is harder to measure than temperature, but it plays an equally important role in the curing of the paint or coating. The ideal is 50% relative humidity, but curing times are significantly affected when humidity levels exceed 70%. In high-humidity situations, surfactant leaching may become apparent - brown or white discoloration on the surface of the paint. This can generally be rinsed off or may be left to wash away with day-to-day weathering.
Check your roofs, external flooring and safety markings ahead of poor, cold, dull and wet weather. We offer a full range to cover these together with comprehensive technical advice…just ask or email us.
If you are looking to paint in more inclement weather we recommend you read our Painting in Cooler Weather Guide beforehand.