Woodsafe Exterior® Fire-X™

Woodsafe Exterior® Fire-X™ fire protection treatment is unique in every way and gives architects the freedom to create with wood, and downstream users the right conditions to use different types of wood in exterior and damp environments. Completely without the need for another protective coating such as opaque facade paint. Woodsafe Exterior® Fire-X™ provides a permanent waterproof fire treatment that allows the wood to age naturally and to be used in wood facades, cladding in balconies, attics, roofs, ceilings, canopies, underground environments (e.g. mining); offshore environments and more. Woodsafe Exterior® Fire-X™ is listed as a leaching resistant treatment in the 2012 UK Wood Protection Association Flame Retardants Manual.  

Woodsafe Exterior® Fire-X™ is DOP declared and CE certified in accordance with EN14915: 2013 for most species of wood, such as cedar, larch, spruce, oak and is technically approved according to SP-105 Fire cladding for cedar woodchips and heat treated pine.  


Woodsafe Exterior® Fire-X™ is composed of non-hygroscopic substances and does not contain substances such as ammonium, urea, di-ammonium, monoammonium, etc.

Personal protection

In accordance with AMV recommendations, please use goggles, gloves and respirators for situations that require them, and provide good ventilation when grinding or generating dust. In cases of acute emergency, contact a doctor by calling 112. In cases of eye injury, rinse gently with warm water from a drinking glass or special water rinsing container until the pain disappears. If irritation persists, contact a doctor by calling 112 and bring the safety data sheet for the product.

Mounting Materials 

International Building Code (IBC) Section 2304.9.5.3. Mounting materials for treated wood used outdoors or in wet or damp places. Attachments, including nuts and washers, for fire-treated wood used outdoors or in wet and damp locations should be stainless steel nails of at least A2 quality. At sea, or in other such locations, at least A4 quality applies. Woodsafe recommend always using stainless steel (A2 or A4) mounting materials, fasteners for wood materials for outside, damp and weather exposed mounting of Woodsafe Exterior® Fire-X ™. This recommendation is particularly important for wood species such as cedar, oak, thermo wood and woods containing tannin, the acidity of the wood, etc.

Building waste 

Building waste with Woodsafe Exterior® Fire-X™ is to be sorted as combustible timber. Burning using your own solid-fuel combustion equipment is not recommended due to deteriorated combustion characteristics, which can damage the equipment. By-products from Woodsafe Exterior® Fire-X ™ such as sawdust, cutter chips and materials should not be used as animal bedding or for the production of solid fuel such as briquettes, pellets, wood chips or suchlike.


Woodsafe Exterior® Fire-X™ has approved resistant properties for exterior applications, including those specified under ASTM 2898D. Woodsafe Exterior® Fire-X™ can be used in damp lake, ocean and coastal environments, with no requirement for surface treatment.


Woodsafe Exterior® Fire-X™ can be cut to length and alignment holes for Eldon, fibre grinding etc. can be installed. However the material must not be adjusted in dimension to the extent that the flame retardant properties are reduced significantly. Please consult Woodsafe support for more information.

Wood contains natural substances 

Some woods have greater or smaller amounts of minerals, resins, lignin, and acid, e.g. tannic acid in oak. Such substances can react under certain conditions in the treatment process where, for instance tannic acid may discolour oak, e.g. with black, blue-black or blue discolouration, and during the drying process, a rash of resin and lignin may occur. This phenomenon can often be polished away, but it is a natural property that is not subject to warranty. The quality of the supplied raw material is of great importance for optimal results. More information can be found in Woodsafe16 Appendix FRW.

Cover painting of facades and wood panelling 

Wood material treated with Woodsafe Exterior® Fire-X™ is not adapted to be painted, and therefore the wood panel must not be top coated. If cover painting is performed anyway, the responsibility for the final result lies with the painter, not with Woodsafe.

Roof ventilation 

Roof ventilation with a natural free flow of air is highly desirable for all kinds wooden ceilings, treated or untreated, because it allows moisture to be discharged whenever the roof is heated by solar radiation, whatever the season. This is due to the "chimney effect" in which air rises naturally when heated. In a sloping roof with eaves ventilation and ridge ventilation, the natural circulation of air removes moisture very effectively. Heated air escapes at the ridge (along with water vapour evaporated from the wood) and simultaneously fresh air is drawn in at the joists. 

The fresh air is heated while rising inside the attic, which reduces its relative humidity and increases its capacity to absorb water vapour. The flow largely stops at night and during cloudy, humid weather because of the lack of solar heat, which means that moist outdoor air is not drawn in at these times.  

 Moisture accumulates in the roof as a result of activities occurring within the living space, such as cooking and showering. The airborne water vapour moves up into the attic through many small "air leakages" at penetrations and at the corners between the walls and ceiling, making it possible for air and airborne moisture to flow upwards to the attic. The moisture often condenses on the cold roof surfaces, which increases the level of moisture in the wood and sometimes causes water to drip onto the insulation. Moisture barriers can reduce the spread of moisture in the attic, but air leakage can carry as much as up to 10 times more moisture into the attic than spreading through the drywall or other material. As a moisture barriers only stop about 10% of the flow of moisture into the roof space, it does not seem logical to halve the minimum free ventilated space required (from 1/150 to 1/300) just because moisture barriers are used.   

Ventilation fans are a dubious solution. Most are temperature-activated, which means that they do not work in the winter when moisture accumulates fastest. They are not a substitute for natural ventilation. Gable vents do not help much either, because no airflow is created if the wind is not blowing exactly right.  

There are no simple answers to the question of how much ventilation is needed in a ceiling. What one can say with certainty is that ventilation should be evenly distributed between the ridge ventilation valves and the valves in the joist system, for both untreated and treated plywood. Hipped roofs, flat roofs and pent roofs are difficult to ventilate properly as their shape prevents effective natural ventilation. Each type must be analyzed individually to ensure good moisture control.  

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