Teknisk specifikation av NTR märkt trä


The main species in the Nordic countries is Scots pine thanks to the suitability for preservative treatment. Preservative treatments make it possible to use scots pine in outdoor applications which ensures local jobs and short transportation. Other species are also used such as Norway spruce. But since Norway spruce is not permeable a special treatment and classification is included in the NTR system.

Durability of NTR marked wood

The NTR system ensures a long service life.

Above ground durability (NTR class AB) is prolonged dramatically – up to 50 years or more depending on the application, e.g. decking is more exposed to weathering than cladding. This means that the service life is increased by up to 5 to 10 times in comparison to untreated wood. In ground contact (NTR class A) e.g. poles the service life is also improved 5 to 10 times compared to untreated wood.

NTR requires field trials for performance documentation which is unique in Europe and ensures that any new product meets the expectations.


The environmental impact of treated wood is highly regulated. The production sites are controlled and environmentally approved by the authorities (work and external environment). Furthermore, the biocides are approved by ECHA (European Chemicals Agency) which administrates biocides at the European level according to the BPR (Biocidal Products Regulatory). The preservative product is approved on a national level based on efficacy and environmental data. All NTR products are approved according to BPR.


Timber used for NTR treament is from sustainable forest (PEFC or FSC). This ensures that forest is cultivated in a sustainable way. Since wood is a renewable material and absorbs CO2 when growing – wood is a sustainable choice contributing to the SDG (Sustainable Development Goals) 12 (responsible production and use) and 13 (climate effort). Wood treatment prolongs the service life of wood products, reducing the replacement rate of the wood products, in turn leading to more resource efficient use of the forests.

Wood processing

Treatment is typically done in a closed pressure vessel where the preservative is penetrating the wood structure (sapwood). NTR controls the production site twice a year which is a unique standard.