Fire retardant for wood

4 23 2019 | Environmental safety | Fire protection

Use non-toxic fire retardants for the on-site treatment of wooden surfaces

Industrial fire protection of wood products speeds up a construction project, but it is not always possible to use certified fire protected wood products on construction sites. In these situations, visible wooden surfaces are treated with a fire retardant on site and a construction authority’s approval for the treatment must be sought afterwards.



The most common reason for an on-site fire protection treatment is that suitable industrially treated products are not available. Sometimes the need for fire protection is only realised during the construction phase.

Only non-toxic fire retardants that are safe for human health and the environment are suitable for on-site use. This ensures that the storage and use of the products as well as the cleaning of the construction site is safe and does not involve unnecessary risks.


When following the given instructions, the treatment of wood products with the non-toxic NT DECO fire retardant ensures fire protection that meets the requirements of Euro class B-s1, d0. In addition, the product protects the wood from the effects of weather, decay and mould. The product has low emissions and is therefore also safe for indoor use.

There are no particular requirements for the transportation and storage of the Nordtreat fire retardants, but adequate ventilation in storage facilities must be ensured even in on-site environments.

The wooden surfaces to be treated must be clean and free of dust. The conditions during treatment and drying must be within the following limits:

  • Temperature of fire retardant +15…+25 °C
  • Air temperature +15…+50 °C
  • Relative humidity 40...65%
  • Wood moisture content 14...18%

The treatment can be done by spraying, brushing or immersing the wood in the retardant. Protective goggles, gloves and clothing are necessary. The fire retardant must be mixed carefully before the treatment.

If the plan is to treat large wooden surfaces with a tinted fire retardant, it is recommended that you first test the product on a small area because different treatment methods and types of wood may affect the tone.

Wooden surfaces should be treated 1 to 3 times at about one-hour intervals to ensure that a sufficient amount of fire retardant (350 g/m2) is absorbed by the wood to achieve the required fire class. After the treatment, the wood product will be dry to touch in approximately 4 hours and the final surface will be ready in approximately two days if the temperature is +20 °C and humidity 40 to 70%.

One of the many benefits of NT DECO is the fact that no other treatments are required. However, if a wood product is damaged during the installation process or products are cut after being treated, the damaged and cut surfaces must be treated with NT DECO.

After the treatment, the tools can be washed with water or water-soluble detergents. Don’t forget to read the instructions for using Nordtreat fire retardants as well as other documents.


Certified fire protected wood products should not be painted or otherwise treated in connection with the installation process because further treatments weaken the required functioning and durability of the fire protection. The only exception is the fire protection treatment of cut surfaces, which is always required. It is recommended that the treatment is done using the same fire retardant that was used during the industrial treatment. The required fire retardant is usually provided by the manufacturer of the fire protected wood products.


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