Painting an Old Exterior Wall – Key Considerations

Painting an old exterior wall is a great way to refresh your home’s appearance and protect it from changing weather conditions. However, before starting the painting project, it’s important to consider a few essential factors to ensure a durable and beautiful result. Proper preparation, such as cleaning the wall, removing flaking paint, and choosing the right paints, is key to achieving a good outcome.

In this article, we’ll go through all the necessary steps for painting an old exterior wall to ensure the paint adheres well and lasts for a long time.

Painting an Old Exterior Wall – 5 Key Considerations

When painting an old exterior wall, it’s important to be aware of and understand these 5 things:

1. Removing old paint
2. Washing the exterior wall before painting
3. Number of paint coats required
4. Choosing the right type of paint
5. Paint drying

In this article, we’ll explain these work stages and their significance in more detail.

Can you paint over old paint?

Yes, painting over old paint is possible, as long as the surface is intact, clean, and in good condition. Before painting walls, it’s important to clean the surface of dust, grease, and other impurities so that the new paint adheres better. Generally, when painting an old exterior wall, the same type of paint is applied over the old paint as was used previously.

If the paint is cracking or flaking, it should be removed before repainting. Additionally, it’s good to ensure that the new paint is compatible with the old paint, as water-based paint may not adhere well to oil-based paint, for example. If the surface is in poor condition, it may be necessary to use a primer before applying the new paint.

Before starting to paint, check the paint manufacturer’s instructions and do a small test on a small area before painting the entire surface.

Does all old paint need to be removed?

Not all old exterior paint needs to be removed, but if the paint has cracked, flaked, or is coming off, it must be removed. This ensures that the new paint adheres properly and the surface becomes durable. If the old paint is in good condition, you can paint directly over it. The most important thing is that the surface is clean and even so that the new paint adheres well.

Properly done paint removal and preparation makes the painting job easier and ensures that the paint surface lasts longer.

How to clean the surface before painting?

If there’s no mold on the wall, it’s enough to brush off dirt and dust from the walls with a dry, soft brush. Washing with water is usually not necessary if there’s no visible dirt on the surface. However, if there is dirt and it doesn’t come off with dry brushing, you can use water and detergent.

At Väriset, we don’t recommend using a pressure washer to clean wooden walls. However, if you decide to use a pressure washer, it’s important to adjust the washing pressure low enough. Most importantly, the painting surface must be clean and dry before painting.

Does the wall need to be sanded before painting?

The exterior wall doesn’t need to be sanded before painting if the surface is otherwise in good condition. It’s enough to brush the walls with a dry, soft brush to remove dust and dirt. You’re probably wondering how to remove old paint before painting. If the old paint is flaking and has partially come off, using a paint scraper is the best way to remove loose paint. Removing old paint with a wire brush is worthwhile, especially with log walls, but you need to be careful not to damage the wood surface too much. Removing old paint from an exterior wall works best with a paint scraper, but you need to be careful with this tool as well.

Should the wall be washed before painting?

We often encounter the question, should the wall be washed before painting. Washing the wall before painting is important for the final result. A clean surface ensures that the paint adheres better and the result is more even.

You can wash the wall with water and, if necessary, use detergents designed for painted surfaces. If there are moldy spots on the wall, you should use a mold cleaner. Let the surface dry thoroughly before painting so that the paint adheres properly.

Is mold cleaning essential when painting an old exterior wall?

If there’s mold or dirt on the wall, the wall must be washed with a mold cleaner before painting. Mold spots should never be left under new paint because they will continue to grow under the paint and eventually cause the paint to peel off. In a previous article, we stated the following:

“If you’re painting a house, you can and should use a mold cleaner, as it’s important to remove dirt and mold spots before applying a new coat of paint.“

How many coats of paint on an exterior wall?

If you want the exterior wall to be as durable as possible, you should paint the wall two or three times. Start with a primer if it’s raw lumber – this helps the paint adhere and protects the wood. After that, apply two topcoats, which make the surface durable and beautiful.

If you’re painting over old paint, a primer may not be necessary, but if the paint is worn or in poor condition, priming the exterior wall may be worthwhile. Remember to let the paint dry thoroughly between coats.

Is primer mandatory?

If you’re treating a new surface and want a clean result, primer is absolutely necessary. It’s an important part of every painting project because it ensures that the topcoat adheres properly and covers well.

Primer creates an even and uniform surface, which is important on wooden surfaces. Topcoat adheres better and more evenly to a primed surface, making the application of topcoat smooth and uneven spots less likely.

People often ask if the color of the primer matters. Generally speaking, primer works best when its color is close to the topcoat color. If you’re going to paint with a light color, light gray or white primer is a good choice, as dark colors won’t show through and the paint’s coverage improves. Many primers can also be tinted to match the topcoat shade.

How do you know what paint the house was painted with?

Determining the paint type can sometimes be challenging. Previous maintenance painting, old documents such as maintenance or renovation invoices can give clues about previously used paint. You can determine the type of exterior wall paint by looking at and touching the surface. Generally, if the color has faded significantly, has some mold spots, and chalky powder comes off on your hand, it’s probably oil-based paint. If, however, the color hasn’t faded significantly and nothing comes off on your hand, it’s probably water-based paint.

If the paint is worn, its structure can also indicate whether it’s acrylic or oil-based paint. If necessary, you can take a paint sample to a laboratory for more detailed analysis.

How long does the wall need to dry before painting?

The wall must be completely dry before painting. After washing, the wall should dry for at least 12 hours. If a mold cleaner was used in the cleaning, check the manufacturer’s instructions, but the drying time is usually similar.

It’s good to remember that a surface that’s too moist can prevent the paint from adhering and cause problems. Avoid painting in direct sunlight, as weather that’s too hot can cause the paint to dry too quickly and bubbles may form on the surface. Painting should be started in the morning when the dew has disappeared and finished before evening dew settles.