If you are a contractor

Woodsafe does not reduce strength, it does not break down wood fibre and it does not generate increased corrosion of fasteners and fixings, something that can be verified by MIL-19140, among other instances.

This is very important to take into account, since there are variants of impregnation and treatment methods that use corrosive agents. Corrosive substances can cause problems such as compromised strength and breakdown of fibres in damp environments, for example.

Substances such as iron(III) phosphate oxidise wood fibre, which renders the wood lifeless and gives it a brownish colour. Other substances in the formula such as ammonium phosphate, urea and diammonium phosphate are in some cases highly hygroscopic and actively contribute to degradation of cellulose.

Impregnation should protect - not damage

It is therefore important - actually the only viable alternative - to choose impregnation that does not impact negatively on the material when it comes to strength, for instance. This is particularly important as regards roof trusses, plywood, glued laminated timber and other strength-graded structural timber.
Woodsafe impregnated with Dricon or Non-Com has several independent certificates to prove that this material is highly suitable in applications such as strength-graded structural timber, timber roof trusses, glued laminated timber, façade-, roof- and wall-panelling, and more.

Tall wooden façades in Br1 buildings

Tall buildings above two storeys have comprehensive regulations regarding wood façades. The entire façade construction as such has four basic criteria that must be met:

1. Fire spread in the façade construction must be prevented.
2. Fire spread along the façade’s surface must be prevented.
3. No part of the façade may collapse and hinder fire-fighting and evacuation operations.
4. The façade shall meet the requirements of a fire-cell separating function vis-à-vis other fire-cells.

These are the requirements, and according to the general advice in 5:631 it is:

• Permissible to use A2-s1,d0.
• Permissible to use SP Fire 105-classed wood.

Technical exchanges may be permitted, for instance with:

• Wood (D-s2,d0), if wood is used to a small extent on the first and second storeys.
• Automatic sprinkler system as per SBF 120:6, with shielding of windows and doors.

However, remember one vital thing: the four requirements above still apply! The general advice is only intended as a guideline, but it does not mean that the façade may be combustible. Sprinklers should secure the façade; residential sprinklers as the sole measure will not provide fire-protection in the façade unless the fire spreads through the window. The problem of course is that fires can start in a number of ways, for instance through:

• Arson outdoors
• Car fires
• Fireworks
• Balcony fires
• Radiated heat
• Aircraft fires