Frequently Asked Questions & Answers Linseed Oil Paint

Linseed oil paint is made from linseed oil and natural pigments. Unlike modern plastic-based paints that form a tight surface layer, linseed oil paint penetrates the wood and creates protection from the inside out. The wood remains breathable, which means it can naturally breathe and regulate moisture.

It provides deep protection by penetrating the wood rather than covering the surface, creating a breathable finish where moisture can move naturally, and ages beautifully with a soft, lively sheen. It is based on natural raw materials and is economical in the long run as it is easy to maintain without needing to be completely scraped off.

Linseed oil paint works excellently both outdoors and indoors. Outdoors, it is suitable for wood, plaster, metal, and even stone, such as facades, windows, fences, and outdoor furniture. Indoors, it can be used on wood, plaster, drywall, and most common surfaces. Keep in mind that linseed oil paint has a longer drying time than water-based paints, which is good to consider when painting indoors in cold or poorly ventilated rooms. All linseed oil paint yellows slightly indoors when there is a lack of sunlight. This is a natural phenomenon that is reversible and disappears when the surface is exposed to daylight again.

Linseed oil naturally breaks down under the sun’s UV rays. Over the years, a thin layer of powder forms on the surface, called chalking. The outermost chalked layer is called the sacrificial layer, and it works just as the name suggests—it sacrifices itself to weather and wind to protect the underlying paint layers. When the sacrificial layer has chalked away, usually a new coat is enough.

Yes. At Ovolin, we mix linseed oil paint according to the NCS system and the Swedish National Heritage Board's color scale. We also have our own color series that we have developed, including Forest Green, Ovolin Ochre, Geranium Green, and Miner’s Blue. We mix the paint by hand, without tinting machines or chemical pastes. This ensures that the color remains stable and consistent over time.

Preparation is crucial; the new paint will never adhere better than the surface it is applied to. Start by brushing off all old chalky paint, then scrape away any loose paint so you have a solid base. Wash with a suitable painter’s detergent and rinse thoroughly with clean water. Let the surface dry properly; the moisture content should not exceed 16%. Replace any rot-damaged wood sections, as rotten wood cannot be painted to look fresh. Sand away any gray wood if the surface has been left unpainted for a long time. If you have algae growth on the facade, you should wash with an algae and mold cleaner and rinse thoroughly before painting.

Linseed oil paint should always be applied with a brush, never with a roller or spray. Rollers and sprayers create paint layers that are too thick and do not dry properly. For exterior walls, round or half-round brushes of good quality are suitable. For window frames, a round or angled brush provides good control and reaches the glazing bead. Indoors, on paneling and moldings, you can apply with an oval or round brush and then smooth out with a wider brush for an even finish. Clean brushes with linseed oil soap or crystal soap and store them lying down or hanging, never standing upright in a jar.

The best painting season is from May to August, but it depends on the weather conditions. The daily temperature should preferably be above 10 degrees Celsius. Avoid painting in direct strong sunlight, when rain is likely, or when heavy dew is expected. Remember that linseed oil paint dries more slowly than modern paints, so plan for sufficient drying time between each coat. The wood's moisture content must not exceed 16% at the time of painting. If you paint on damp wood, the linseed oil cannot penetrate properly, which risks paint peeling and blistering.

The basic rule is simple: thin and worked in. Work the paint into the surface instead of just applying it on top. Spread it out thoroughly; a thin layer is always better than a thick one. Always stir the paint before you start. If a skin has formed on the surface, carefully remove it without mixing it back into the paint to avoid flakes. Newly painted linseed oil paint is almost mirror-glossy, but after 2 to 3 months, the paint has settled into a semi-gloss finish.

For outdoor use on new or fully scraped surfaces, three coats are recommended. The primer coat is applied with the paint diluted with about 40% solvent for good penetration. The intermediate coat is applied with about 20% dilution after at least 36 to 48 hours. The final coat is applied with undiluted paint after an additional 36 to 48 hours. On chalky outdoor surfaces, one to two coats are sufficient depending on the extent of deterioration. Indoors, two to three coats on untreated surfaces provide a beautiful, opaque finish.

Outdoors, no separate primer is needed; the first coat of diluted linseed oil paint acts as a primer. Indoors, it can be beneficial to prime new or absorbent surfaces with a linseed oil base. This creates an even, non-absorbent surface and reduces the risk of dull spots. Remember to always tint the primer in the same color as the topcoat.

Knots can bleed resin for a long time, which can show through the paint. Indoors, you can shellac the knots with genuine shellac before painting; this seals and prevents bleeding. Always use genuine shellac, not plastic-based knot sealer, when painting with linseed oil paint. Outdoors, shellac does not work because it prevents the linseed oil from penetrating. Sand the knot extra carefully and prime that area once more. Some knots may still bleed through over the years and will need to be repainted during the next maintenance cycle.

Narrow cracks up to 2 to 3 mm in a planed panel or trim can be filled with linseed oil putty. First, paint the crack and then apply the putty wet-on-wet, that is, before the paint underneath has dried. Larger damages should be repaired with wood restoration or panel replacement.

Generally, you should allow 1 to 2 days per coat. The drying time is shortened by heat, light, and low humidity. It's better to wait a little longer than a little shorter. If you paint the next coat too soon, you risk bubbles and wrinkles.

Linseed paint does not dry like regular paint. Instead of water evaporating, the drying occurs through a chemical process with the help of oxygen in the air. This means good air circulation is crucial, especially indoors. Open windows and doors and consider using a fan. If the oxygen runs out, the drying process can completely stop. If you have applied the paint too thickly, it can cause the surface layer to dry while the inner layers are still wet, which risks blistering and a very long drying time.

Bubbles almost always occur for one of three reasons: the paint was applied too thickly so that the surface layer dries while the inner layers are still wet, the next coat was applied too soon before the previous one had properly dried, or the surface was dirty, greasy, or damp at the time of painting. Scrape off the bubbles, let the surface dry thoroughly, and then touch up with a thin coat.

Wrinkles occur when the surface layer dries too quickly compared to the inner layers, often because the paint was applied too thickly or the next layer was applied too soon. Scrape off the wrinkled area, let it dry completely, and touch up with a thin layer.

Blotching occurs when the surface absorbs unevenly. The linseed oil molecules are very small and penetrate where the pores in the wood are open. If the wood absorbs more in one spot, it appears as uneven gloss. Wait 2 to 3 months and allow the paint to cure properly; as the linseed oil fully hardens, the blotching often evens out. Then, if necessary, apply a new topcoat. Otherwise, there is a risk that the blotching will persist.

Black spots are either dirt from the air or algae growth. Algae growth usually occurs in environments with increased humidity, such as on the north side of the house. If it is dirt, wash with a pH-neutral cleaner and rinse with water. If it is algae growth, wash with algae and mold cleaner and rinse thoroughly with clean water.

Since the linseed oil penetrates the wood and protects it from within, repainting is often an aesthetic matter. Outdoors, the sun gradually chalks the paint. If only the top layer has chalked away, a new coat is enough. If the intermediate coat has also chalked, you should apply two new layers. If the paint has cracked in a crocodile skin pattern, it’s time to remove as much old paint as possible, prime all bare wood areas, and then apply two new layers.

Clean brushes with linseed soap or crystal soap and then rinse in lukewarm water. It is gentle on the bristles and good for the environment. If you plan to continue painting the next day, you can store the brush in water overnight, but make sure to clean it thoroughly when you are finished. Always store brushes lying down or hanging, never standing upright in a jar.

Linseed oil paint requires a slightly different technique than modern plastic paints. Make sure to hire a painter with documented experience specifically in linseed oil paint; it’s not enough that the company has done it before, the individual painter should also have personal experience. Ask for references and look at previous work. Ensure the quote reflects the drying time and the correct number of coats, and agree in advance on how any blisters, wrinkles, or runs will be handled.