EXTERIOR PAINTING
Proper Preparation Leads to Smooth Painting and Saves Your Sanity
Spring and summer are peak seasons for home painters. What paint should you choose for the walls? The basic principle of renovation painting is always to apply the same type of paint over the existing one. This way, you avoid the most common mistake.
Weather Conditions
Weather conditions greatly affect the success of a painting job. Of course, you shouldn’t paint in the rain, and direct sunlight is not ideal either. Under the sun, the paint surface may dry too quickly, resulting in a less durable and less visually appealing finish. It’s also not advisable to start painting in the evening, as the cooling air may cause dew to form on the freshly painted surface. This is especially important when painting roofs. High relative humidity slows the drying of water-based paints and encourages the growth of mould and blue stain fungi.
Preliminary Work
Start by removing dust and dirt from the surfaces to be painted. If the wood surface shows signs of blue stain or mould, they can be removed with Fintex Mould Removal and Prevention Agent. After washing, allow the surfaces to dry thoroughly. No extra rinsing is needed, as Fintex Mould Removal and Prevention Agent does not contain hypochlorite.
All paint that is poorly adhered to the surface should be removed mechanically by scraping or sanding. Sanding and scraping are laborious but rewarding. A heat gun can be used on small surfaces, such as door and window frames. Softened wood fibers should be brushed off with a wire brush. Paint adheres better to a hard, solid surface than to a fibrous and soft one.
Knots and resin spots should be treated with knotting varnish if you’re using an opaque paint. Skip knotting varnish if the building is to be painted with a translucent wood stain. Wood stain does not adhere well to knotting varnish, leaving the treated area lighter than the rest of the surface. Knotting varnish should also not be used when painting with Fintex Petroliöljymaali, as it will result in a different gloss level.
Determine the Type of Previously Used Paint
Determining the previous paint type requires either good memory or detective skills. The first task for a home painter is to find out what type of paint was previously used on the building.
The simplest approach is to use the same type of paint as before. You can usually paint over old oil paint with latex paint without much concern. However, converting an old latex surface to an oil-based one is a more challenging task and should be left to professionals. Oil paint will adhere to water-based paint, but it can soften it, risking the old paint peeling away from the surface.
You can recognize old oil paint by its crocodile-like texture, full of small cracks.
Latex paint cracks along the wood grain and is flexible when you peel off a strip.
Planning the Work
Before starting the painting job, it’s important to plan the boundaries between different surfaces and the order of work. Don’t take a coffee or meal break in the middle of a long wall surface, as this will leave a visible seam at the starting point.
Prepare any hard-to-move scaffolding in advance. However, lightweight, quickly assembled, and safe scaffolding is available for rent, even for home painters.
Where to start: a right-handed person should always start from the right and the top, using their left hand for support on an unpainted surface if needed. A left-handed person should do the opposite.
Applying two thin coats of paint protects the wood better than one thick coat.
When painting new wood, it’s advisable to first spray a diluted mixture of Fintex Mould Removal and Prevention Agent (diluted about 1:7) on the surface. The first coat should be applied with thinned paint to help it penetrate the wood better. The paint can’s label will tell you what thinner to use.
Use plenty of paint. Only then will you achieve an even finish. As my father used to say, “Paint with paint, not with a brush.” Ensure that the paint is worked thoroughly into the wood, even though the process is called brushing. Brushing is something entirely different, and it doesn’t happen on an exterior wall. And before dipping the brush back into the paint, smooth out the already applied paint with strokes along the wood grain. Once one wall has been painted, take a break to plan the next steps. Allow oil paint to dry for at least a day, and the same applies to latex. So, no rush. And a careful painter checks the freshly painted surface after about fifteen minutes to catch any drips.
If the old paint surface is intact and unfaded, and only requires washing, this can be done with Fintex Mould Removal and Prevention Agent. It does not need to be rinsed off and does not damage windows or the paint surface.
Two Coats of Paint Provide Durability
When using Fintex Oil Paint, the first coat should be applied with paint thinned by about 10%. The brush should be used firmly, not gently. The second coat should be applied with unthinned paint, and no sooner than the next day.
When using Fintex Exterior Paint, the rules are the same as above. It’s also advisable to apply latex paint in two coats. Experience has shown that a surface painted in one coat tends to develop visible work seams over time.
With Fintex Petroleum Oil Paint, one coat is usually sufficient. However, a smoother and more durable surface can be achieved by applying two coats. This also significantly reduces the risk of visible work seams.
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Ari Salmela
Industrial Sales and Technical Support
Fintex-Tetrakem Oy
