Exterior painting

Roofs and metal surfaces

Instructions - Roofs

Before treatment

  • Painting conditions must be taken into account before work begins. The surface must be dry before treatment. The air temperature must be at least +5°C around the clock when using Rostex Super, Panssarimaali, Miranol and Unica; +8 °C - +25 °C when using Hammerite and at least +10°C when using Repco. The surface temperature must not exceed +40°C. Relative humidity must be below 80%.

  • Always read the instructions on the product label before use. Read the product descriptions for more detailed information about paint specifications.

  • Choose an undercoat that is as close in colour as possible to the topcoat.

  • Stir the paints well before and during use, also after thinning.

  • Multiply the length by the width to calculate the surface area to be painted. For corrugated surfaces, multiply the surface area by 1.5.

During treatment

  • Start painting in good time so that the paint film is surface dry before the evening dew falls, since this slows down paint drying. If the film on the paint surface is damp, blotches and dull patches may occur. 
  • Avoid painting in direct sunlight. The best weather for painting is when it is overcast. 
  • Avoid painting thick coats, since they dry very slowly and wrinkle as they dry.

After treatment

  • Let the paint dry properly. For paints and lacquers, surface dry is not sufficient. Depending on the product and coat thickness, final drying may take anything from a few days to two weeks.

  • If there is any paint or lacquer left over, put the lid carefully back on the can to form a tight fit. Turn the can upside down for a moment to make the lid airtight. Opened and/or tinted products cannot withstand prolonged storage.

  • Take liquid paint waste to a hazardous waste collection point. Empty or dry cans can be taken to a recycling point or to a public waste disposal site.

Maintenance instructions

> On-site and pre-painted metal surfaces