The weather should have been warm and dry for several days before painting commences. The best time of the year for painting is usually the period between June and August, but regardless of the season, painting should be done in time so that the paint has dried well before darkness comes with dew or frost. Also avoid to paint on surfaces which are warm from being heated by the sun.
New timber should preferably be painted as soon as possible after put in place. Where the timber has been painted indoors before being set in place, avoid painting extremely dry timber (moisture content 6-8%). This may be the case, for example, where timber has been stored indoors in a boiler house or the like. If this happens, the timber will come to swell to its maximum capacity when subsequently achieving its normal outdoor moisture content (12-18%). The elasticity of strong paints (various oil-based paints) can then become much reduced, with paint fracture as a result.
In order to be able to choose the right sort of paint, it is important to know which type of paint was previously used in the house. The general rule is to use the same type as was used before. It is quite inadvisable to paint over a surface which has previously been painted with acrylic paint using a strong alkyd paint because they have differing elasticity, and can therefore come to glide against each other during temperature changes. The risk of fracturing and paint seepage would then increase. Also, surfaces previously painted with an emulsion paint (e.g. Falu Rödfärg) are usually (in the absence of effective removal of all the old emulsion) unsuited to repainting with any other type of paint than emulsion paint.
– Rub the surface down with sandpaper. If the paint clings to the paper, it is quite likely to have been an acrylic paint (plastic-based paint). If, on the other hand, a fairly loose dust is raised, it is quite likely to have been an alkyd or linseed oil-based paint.
– On a light surface, you might try placing a drop of caustic solution/lye. If the surface turns a yellowy brown after a couple of minutes, it is an alkyd paint.
– Another method is to rub a cloth dampened in turpentine solution on the surface. If the paint becomes soft (loosens up) and leaves a colour very easily, it is an acrylic paint.
The base surface must be dry and firm. Loose paint is removed either by scraping and/or steel brushing. Softened timber (subject to dry rot) must be removed/replaced.
Dirty surfaces can be cleaned with mould wash and rinsed with water. Surfaces affected by fungus and mould can be treated with disinfection after washing and rinsing. If cleaning was done with a high pressure cleaner, you need to allow 2-3 weeks of dry weather before you can be sure that all water which was forced into cracks and under panels has evaporated and completely dried out. Apply using a compact brush and work the paint well into the timber. Take special care to do a proper job on end grains and timber joints. These surfaces should first be coated with Grund I H20 or Klassisk Primer Oil before the undercoat is applied. It is better to apply several thin coats, with a couple of drying out days in between, rather than a few thick coats. Avoid painting on heated surfaces or surfaces which have been exposed to sunlight. The heat ensures that the solvent is quickly pressed out, and the binding agent does not get the time to penetrate into the timber, with poor adhesion as the result.
Be very precise when treating end grains and joints. Prime with Grund I H20 or Klassisk Primer Oil on stripped wood surfaces and apply a base coat with Grund II H20 or Klassisk Undercoat. Thereafter, paint over once or twice with Storm Outdoor Acrylic, Solid Opaque Woodstain or Stabil Opaque Woodstain. Make sure that the previous coat has dried out properly before applying the next layer. This can take several days during cold and damp weather conditions. You can check this by pressing hard on the paint with your thumb; if the surface coat glides, the paint is not sufficiently dried out.
Dirty facades are cleaned with facade wash, followed by a very thorough rinsing. In the event that the facade has also been affected by fungus and mould (black dots), it should be disinfected by applying distinctive product and allowing this to dry for one whole day before painting over. Alkyd oil-based paints have natural matting down and bleaching properties, which are enhanced when exposed to the south and east side of the house, where UV-values are at their highest. A more frequent maintenance regime may be necessary on those areas.