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Guide: Care and maintenance of oak doors and exterior oak doors

Caring for and treating your door is not just a chore. It is also relaxing work that produces results. Especially on older doors, the result is usually great when you have sanded away the top layers of old oak and encounter the door you once loved. In this guide, we look at how you take care of your oak door to preserve both function and appearance throughout the lifetime of the door.

Why is maintenance important?

Oak (Quercus robur) is a hard, durable and rot-resistant wood. The fact that it is hard means that oil does not penetrate as easily as for example teak. This means that you need to oil an oak door more often than other doors. But as with all wood, oak demands continuous maintenance. In this guide, we tell you how much maintenance you need to do, based on the age of the door. But first: why should you maintain an oak door regularly?

Maintenance preserves the colour tone and appearance of the oak door

Oak is a light wood that fades and turns grey if it is not maintained. Oak trees also have larger pores than other woods. When the tannins found naturally in the oak oxidise and penetrate the wooden pores, black spots may occur. Similar spots occur when mould and pollen stick in the spores. Both of these are difficult to sand away once they have appeared.



Maintenance preserves the door’s function

The exterior door is the house’s boundary the between indoor and outdoor climate. On the outside of the door, there may be dry air with minus degrees, while the air indoors is above 20 degrees and humid. As a consequence, the door’s wood is exposed to great differences in both temperature and humidity. Maintaining the door makes it more responsive and avoids cracking. This makes the door last longer

All oak doors need maintenance. Exactly how often depends on the door’s location and exposure to weather and wind. Remember that an oak door needs to be oiled to prevent it from becoming unsightly, cracking and getting black spots.

When is it even more important to maintain your oak doors?
An exterior door installed in a place without the protection of a roof or in coastal areas requires a little extra care and maintenance. It is also extra important to maintain doors facing south and west, especially those parts of the door that are most exposed, such as the bottom of the door where water splashes up. If you do not maintain the door, the colour tones on its wooden surface may change.
// Leif Karlsson, door builder, Bovallstrand.

When the oak door is new – maintenance is easier

When your oak door is new, it is sufficient to wash the door once or twice a year. It is good to get into the routine of washing the door in early autumn and early summer. Dip a sponge or cloth in hot water mixed with detergent and wash off the door leaf and frame. If the door feels dry it may be necessary to place a thin layer of oil.

Our oak doors are treated with a layer of Osmo UV Protection Oil 425 Oak (pigmented) and a layer of Osmo UV Protection Oil 420 (uncoloured). This means that they have a good base protection.

For older doors: thorough maintenance

When the door starts to get few years’ old, we recommend that you do a little more thorough maintenance a few times a year. How to do it:

1. If the wood fibres have lifted, start by sanding the surface with a fine sandpaper in the direction of the wood grain. Use a fine sandpaper to sand away dirt and organic material stuck to the surface.

2. Then apply a thin layer of Osmo UV Protection Oil 420 (uncoloured). If you sand off the door completely, you should base with a layer of Osmo UV Protection Oil 425 Oak (pigmented) and then a layer of Osmo UV Protection Oil 420 (uncoloured) as top, after sanding the surface.

3. Be sure not to leave any excess. Avoid treating your door in direct sunlight.


Wash off visible mould a few times a year

If you see that there is mould on the door in the form of small black spots, you should treat it with algae or mould spray that kills the mould. Wash your door a couple of times a year, especially if there are many hardwood trees in the surrounding area. This will keep it fresh while allowing it to age beautifully and naturally. If you do not know which mould spray to use, ask your paint merchant so they can help you find the right one for your door.

Apply an extra layer of oil when needed

We also recommend that you add an extra layer of oil when needed. Exactly how often depends on the door’s location and exposure to weather and wind. Remember that your oak door needs to be oiled to retain its appearance and not crack and get black spots.

Remember that you should apply the oil at a time when there are not too many mould spores or pollen in the air, as these easily stick to the door.

For further maintenance, ask your paint merchant for advice or visit

Maintenance of glazed oak door/exterior door

Check regularly that the silicone seal between the glass and the glass strip is intact. The silicone material is broken down by the weather and wind and allows water to penetrate into the structure and cause swelling and possibly colour loss. Use silicone adapted for glass (available in building materials merchants) for maintenance. Ask your paint merchant for advice.

Video: Maintenance of an oak door in Bovallstrand

Leif Karlsson is a door builder and has worked at Bovalls Dörrbyggeri since 1969. His hobbies are carpentry, local history and writing. Here he shares good door tips and shows how to carry out thorough maintenance on an oak door from Bovalls. NOTE! If the oak door only needs renovation oiling, there is no need to use preservative.

Want to know more about our oak doors or book a visit to our showroom?

We look forward to hearing from you at or call +46 (0)52 351700.

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