Maintaining and restoring wooden window frames: step by step

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Maintaining and restoring wooden window frames: step by step

Restoring wooden window frames needs usually more than just a bit of paint

Maintaining or restoring wooden frames is a lot of work. The paint cannot simply be applied on the old wooden frame, but the frame has yet to be prepared.

  1. Before the paint can be applied, the old paint and varnish remnants must be removed, with abrasive paper and little pressure, layer by layer.
  2. When grinding, a lot of dust is generated which, of course, should not remain on the window frame. Dust and dirt from grinding can be removed with a soft cloth or a vacuum cleaner.
  3. If there are still residues of old paint or varnish layers on or in the wood, it is also possible to use strippers for removal. However, these must be neutralized before the window frame is further treated.
  4. Before the window frames receive their new coat, the seals must be inspected. If there is moisture between frame and glass, the old putty must be removed. However, new putty is only applied after the coating.
  5. Sometimes the weather has a bad effect on the wooden frame. Restoring in this case means that the finer and coarser cracks in the wood have to be closed. The first step is to free the cracks from dirt and dust.
  6. After that, the small cracks have to be extended slightly. For filling, a filling paste is used, which is available in the optics of different woods and in different color nuances. The paste is safe, it only seals the crack so far that no moisture penetrates into the wood.
  7. Before applying a glaze or a paint to the wooden frame, the areas with the filling past must be carefully grinded and levelled out. This can be done by hand with a piece of sandpaper.
  8. Comprehensive restoration of window frames is a time-consuming matter, especially when the wooden frames are quite old. The material is protected against weathering and moisture only if water cannot penetrate. Therefore, the cracks must be properly closed, even if this sometimes means three-, four- or five times grinding and filling.
  9. Before painting, the glass pane is covered up with painter's masking tape, which makes the application easier. Glazes, paints and oils give the wood back its beautiful, natural coloring, emphasize the grain structure and protect it from environmental influences. Some of the products have a profound effect, so they maintain and protect the wood structures not only on the surface.
  10. Only when the last layers of glaze or paint are dry, the putty between the pane and the wooden frame should be re-applied.

Different types of wood require different care

Which care products are used in the environmentally conscious and careful restoration of old window frames depends not only on the condition of the frames and their use, but also on the type of wood. Oak, for example, darkens with time, which is also desired. Old oakwood looks beautiful and is relatively hard. Tropical woods are also very hard and provide natural weather protection. They are treated differently than soft, domestic woods. Furthermore the color of the wood has an influence on the extent to which the solar radiation affects the wood. Very dark wooden frames heat up more under sunlight and expand accordingly. If it cools off in the evening, they contract again. Dark wood works more than light wood. Some paints and glazes do not tolerate this. They crack in case of a strong expansion of the substrate. Therefore it makes sense to really pay attention to the quality and the suitability of the products. Besides the color of the wood the resistance to insects is important. Among the domestic woods, spruce is a very soft wood and has a low bulk density, which makes it more vulnerable. Hard oak and tropical woods, on the other hand, have the reputation of being particularly resistant. Their high bulk density thus has an influence on the durability and therefore on the composition and the properties of the glazes and paints used when restoring the window frames. Nevertheless, also durable window frames with high bulk density must be treated every three to five years in order to last long. Of course, there are also differences in color: pine and spruce are very light woods, oak is quite light when still young and darkens with the years, beech also. Larch is light and has a reddish tinge, while tropical woods can be lighter or darker, yellowish or reddish brown.

Untreated coniferous and hardwood

Untreated wood is easy to restore and requires less work steps. Untreated means that no deeply penetrating chemicals were used which would have to be removed before the application of the care products. The ADAO-External Primer N° 259 is well suited for an initial treatment. For the post treatment, two products are recommended: KALDET-All-weather stain N° 281 or VINDO-Natural gloss paint N° 629. This is a deep-penetrating pretreatment which is followed either by a thin color-neutral stain layer or by a covering paint layer, which both show the grain of the wood. These products can be used inside and outside. As a neutral layer for inside, you can use the DUBNO-Priming Oil N° 262 for the initial treatment and the KALDET-Transparent wood stain N° 270 for post treatment and maintenance. The wood stain is odorless and available in many different color shades. Larch and robinia In the case of larch and robinia, we recommend our ALIS-Decking oil N° 579 for the initial treatment. This oil is also suitable for post treatment and maintenance. The oil provides a water-repellent, fast-drying coating on the surface, which is available in different color nuances and enhances the natural appearance of the wood. It protects the wood from moisture. The product is suitable for both indoor and outdoor treatment.


Oak should be treated with the LINUS-Penetrating oak priming oil N° 233 or the ALIS-Decking oil N° 579 for initial treatment. For the restoration we recommend different products with different properties: The KALDET-All-weather stain N° 281 offers a deep-penetrating pre-treatment. It is weather-resistant and available in different color shades. The VINDO-Natural gloss paint N° 629 also offers a deep-penetrating pre-treatment, but it stays as a glossy, covering layer on the surface. It is available in different colors, too. If the window frame of oak was originally treated with ALIS-Decking Oil, ALIS can be reused during restoration. The oil provides a water repellent, fast drying coating in different colors. All products can be used both inside and outside.

Tropical timber

Fort he initial treatment of tropical timber we recommend the DUBNO-Priming oil N° 261 or the ALIS-Decking oil N° 579. The KALDET-All-weather stain N° 281 is suitable for the restoration and and a regular maintenance. It offers a deep-penetrating pre-treatment and leaves a weather-resistant thin glaze-layer on the surface. The glaze is decorative and silky. As an alternative, you can use the ALIS-Decking oil fort he restoration. The oil protects the wood from weather influences and it is available in different colors.


For the restoration of old window frames you need a paint stripper. Alkyd resin-containing old paints are quickly and gently removed with help of the TAKETI-Paint stripper N° 554. The removal is quite simple. However, the paint stripper must be neutralized before further treatment. The way the wood needs to be treated afterwards depends, however, on the type of wood. For the filling of cracks during the renovation of window frames, we recommend BASKO-Wood floor putty N° 725 or TAISTO-Linseed oil putty N° 541.


There are special products, which are only intended for the post-treatment and the maintenance of wooden frames. They do not give the wood a new paint layer, but they clean it and fresh it up. The KALDET-After care N° 276, for example, ensures that the window frame looks well-maintained and clean and is protected against any weather conditions for a long time. The right treatment allows you to extend the post-treatment interval by up to one year.

Sometimes less is more...

The LIVOS product line “LIVOS neutral” offers special glazes and oils for allergy sufferers. However, these are not suitable for ALL work on the window frames. Untreated coniferous and deciduous wood in the inside area can be treated with the DUBNO-Priming oil N° 262, for the post-treatment and maintenance we recommend the KALDET-Transparent wood stain N° 270. Both products are also suitable for wood-aluminum windows, for all kinds of wood, as long as the windows are fully assembled. This stain provides an odorless coating and is available in various colors.

LIVOS neutral for untreated needle and deciduous woods

The KALDET-Transparent wood stain N° 270 is translucent and intensifies the color effect of the wood so that the grain appears really beautiful. The product is available in different colors so that it can be used for various deciduous and coniferous woods. This stain is thin and almost invisible on the wood, it lets water repel and protects the wood from moisture. However, the product is only suitable for indoor use. Outside it does not provide enough protection from the weather. Wood-aluminum windows consist of aluminum frames inside in the functional parts. The frames are veneered in the visible areas, so they look like "real" wooden window frames. Here it is very important that moisture cannot enter the interior of the frame between the different material layers. The KALDET-Transparent wood stain N° 270 is suitable for all types of wood of finished wood-aluminum windows.

Good for the environment, good for the health

The LIVOS wood care products are varied and offer exactly the right care for window frames. It does not matter if you simply maintain your wooden frames on a regular basis, whether you restore old frames and protect them permanently, whether you have used tropical wood or native wood for your window frames – you will find the right product. The LIVOS oils and glazes are made of natural ingredients and respect the environment and your health. LIVOS neutral offers wood care products especially for the needs of allergy sufferers, which are applied in the interior and do not emit any harmful chemicals to the room air.

Photo Credits: © Hafize Çakmak-