Below we provide answers to frequently asked questions. Is your question not listed? Please contact us. We will be happy to tell you more.

We purchase the wood and then burn it in our self-developed oven in our workshop in Leersum. From there we deliver it to our customers.

There are plenty of examples on YouTube where people use a roof burner to treat planks. This way of burning wood is very different from the method we use. In our self-developed oven we can influence the temperature and amount of oxygen we use to "charcoal" the wood. This process can be compared to pyrolysis. We work with different types of wood, each of which undergoes its own treatment.

By treating the wood with a roof burner, the wood is "burned" in an oxygen-rich environment. This makes the carbon layer of the wood brittle and will quickly damage and weather.

This is possible in consultation.

Yes, it is. Our beautiful black wood now adorns many a garden. Please note: the back of the wood is usually not burned. Abrasive plants (e.g. due to the wind) can rub off the carbon layer. Many of our customers appreciate the natural aging of the wood and the wear and tear over time. This fits within the Japanese life philosophy of Wabi Sabi. We will be happy to advise you which of our products is most suitable for your garden.

Due to the carbon layer most of our charred wood species are not suitable for use on floors and stairs. Frequent walking will damage the carbon layer.

Unfixed wood gives off after charring. For indoor use we always fix the charred wood. The charred layer becomes a bit more matt in appearance and will stain less. For the exterior we often advise not to fix the wood. This ensures that the charred wood retains a beautiful, natural shine and is also more durable than when the wood is fixed. In the course of time the release of the wood will decrease and for a number of variants this will eventually stop. Most burned types of wood, also for exterior use, can also be fixed if desired. We will be happy to advise you about this.

Our burned species, the planks with a carbon structure, are only burned on the front and side. In consultation, we can also burn the back of the planks. The versions that are burned and brushed, planks with a grain structure, we finish all around with a stain.

We recommend mounting the wood with countersunk stainless steel screws with a black head. This makes the assembly almost invisible. With your order we can deliver these stainless steel screws with black head. These are almost invisible in the carbon layer. The wood may not be nailed, this can damage the carbon layer. Most variants cannot be glued either.

We will gladly advise you with regard to assembly. We can also take this off your hands with our Zwarthout Assembly Service.

Yes, we can. In consultation, our experts can assemble our wood for you in the best and most aesthetically pleasing way. This service is available for projects in the Netherlands, Belgium, parts of France an Germany.

In order to make an offer for assembly we need drawings of your work. Please contact us for more information

For most variants we have the raw wood in a limited number of standard sizes in stock. Orders of up to 50m2 in standard sizes can usually be delivered in two to three weeks. For larger orders and deviating sizes, please take into account a delivery time of six to eight weeks.

We deliver the wood to our customers as soon as possible after burning. Because we make the wood to order, the wood can still smell like "burned wood". The smell will fade away over time.

This depends on the type, but in principle the carbon layer of our burnt wood weathers under the influence of wind, rain and hail. The lifespan of the carbon layer depends on the orientation of the facade and the location of the building. The black carbon layer of our burnt wood ages over the years and then acquires a beautiful patina (weathering), such as a light sheen, or a craquelé surface, for example. The natural aging and weathering over time does not detract from the visual appeal, on the contrary, it contributes to it! This fits within the Japanese philosophy of life of Wabi Sabi. On the product data sheets of our products (downloadable on the product page), you can see how the wood ages.

In the non-fixed variants of our charred wood, the carbon layer remains vulnerable. Small pieces can break off on impact. 

The service life of the wood depends on the durability class of the wood species and the detailing of the building. The carbon layer of the burnt wood weathers outdoors in the long run under the influence of wind, rain and hail. The lifespan of the carbon layer depends on the orientation of the facade and the location of the building. Please contact us for more information.

When used indoors, the wood lasts as long as untreated wood, i.e. many decades. Moreover, this wood is fixed, making it less vulnerable.

We give a guarantee on the quality of the wood upon delivery. The boards are delivered without defects and will be replaced free of charge if technical defects occur in the first two years. This includes, for example, the tearing of wood or the failure of knots. It goes without saying that the planks must be assembled correctly. We will be happy to advise you on this.

There is no guarantee on the carbon layer itself. All layers of carbon are more or less vulnerable. The detailed provisions can be found in our General Terms and Conditions.

Unfixed planks with a carbon layer do not require any maintenance.

Planks that have been burned and brushed have a stain or oil layer. This wood requires periodic maintenance every three to six years. If you do not maintain Shodoshima / Takamatsu / Sakaide exterior, the stain layer will eventually harden and flake. Below this, the white wood will emerge and 'age'.

The product specification sheet that you will find on each product page explains exactly if and what maintenance the different products need.

During the charring of the top layer, the gases released are collected in the oven. At another point in the process, oxygen is added to these gases, causing them to ignite. This provides the heat needed for charring the wood.

Gas is only added at start-up, after that the wood burns almost entirely on the gases released during the process.