Treatment and Guides

Treating wood with Sioo:x Impregnation

Sioo:x is a wood modification system which to work effectively needs to penetrate the timber substrate as far as possible.


The SiOO:X Wood Protection system is very easy to apply. The fluids have a viscosity just less than water and flow and coat extremely effectively. The treatment should be applied by factory coating (or by hand for maintenance and sealing} by SiOO:X approved distributors and specialist coaters. Fully factory finished timber ensures that the treatment is applied under controlled factory conditions, no matter how challenging the weather is outside and is strongly preferred.


SiOO:X is designed for treatment to professional standards. In wet and humid maritime climates, such as apply in the United Kingdom and Ireland, it is particularly important to achieve maximum impregnation of the SiOO:X treatment into the surface substrate and into all surfaces, edges, end grains and any tongue and groove details. It is highly advisable to treat the back sides of timber exposed to external conditions. Any sawn ends, created in the factory or during site construction must be treated with the SiOO:X End Grain Sealer or a proprietary end grain sealer. Good penetration of the wood is the key to a good finish and long life.


To achieve the best professional standards and maximum penetration it is necessary to apply the treatment to sawn surfaces. On planed surfaces it is important to remove machine glaze (using no finer than an 60 grit paper) to allow the treatment to penetrate the wood structure.


For new timber the best professional results are obtained by having the timber treated by SiOO:X approved factory coaters in controlled factory conditions resulting in optimum application rates and drying environment. The best results are obtained on kiln dried timber below 20% moisture content. Treated timber should be separated on drying racks and ideally allowed to stand for an initial curing period before shipment. The curing process is initiated by spraying with water.


On delivery to the project site, treated timber should be separated and any protective wrapping removed to allow air circulation. Store under cover – not in exposed ground contact situations.


The treatment should be applied in dry conditions and in a good drying environment at temperatures above 10 degrees centigrade. Hand treatment works well for small projects but unless the timber can be treated adequately inside, the best time to treat outside is in the spring and summer months. Outdoor treatment between October and April is not recommended.


Factory coating gives better quality and production control for larger private and commercial projects and containers of 10 liter size and over are supplied For Industrial Application Only.


Both components are entirely environmentally friendly and contain no toxins and are emission free. They can be applied by hand taking the normal precaution to protect the face and hands and with the confidence of no contamination risk in sensitive multi-product factory coating environments.

Preparation and Application

Sioo:x is a penetrant. To achieve the best performance it needs to be able to penetrate the timber substrate to a sufficient depth.

There are good practices that need to be adhered to including:


  • A sawn surface finish should be chosen wherever possible as this opens the surface so that the maximum penetration of the SiOO:X products into the timber occurs by surface coating.
  • Planed dressed surfaces should not be used as the smooth glazed surface resists penetration. If the timber is supplied in a dressed form it must be sanded with no finer sanding paper than a 60 grit grade.
  • All sharp board edges and sill edges should be removed.
  • The timber should be kiln dried to a preferable 16% moisture content.
  • The Sioo:x treatment should be factory applied by a Sioo:x approved distributor/coater in factory controlled conditions.
  • The treatment should be applied to all timber surfaces, the back and front, and all timber edges.

Coverage rates

Sioo:x Premium Wood Protector (also the light-grey and mid-grey products):

First treatment coat – 6-8 m² per litre

Second treatment coat – 10-12 m² per litre


Sioo:x Premium Surface Protector (also the light grey and mid-grey products)

Final coat –  8-12 m² per litre


N.B Consumption of the treatment fluid varies depending on the type of wood, surface structure, moisture content and age.

The thermo wood is penetrated by the treatment extremely well at rates up to 50% more than the above.

Cleaning and Maintenance

Wood is a natural material and even when treated with a wood protector or a preservative can be impacted by dirt and atmospheric fallout including fungal spore. Urban environments are particularly prone but rural environments are not immune as agricultural pollutants and airborne particles can be carried over considerable distances. Dirt and pollution can lead to the formation of algae and fungal growth. Although the Sioo:x treatment provides protective resistance to the penetration of algae and fungi, in humid climates such as the UK and Ireland, they can in some locations take hold on the surface and have a negative aesthetic effect.


The key is to understand that timber surfaces, no matter how treated, need to be cared for and maintained. Early removal of accumulating dirt and any early stage algae or fungal spore through a regular care and maintenance programme will lead to a sustained beautiful appearance. The majority of projects see no impact – it is a matter of particular environments.


Just as you would not allow flooring or other surfaces in your home to accumulate dirt and dust, timber decking, cladding and fencing require care to keep them looking at their best.

The cleaning of Sioo:x treated surfaces is much easier as the surface is toughened by the treatment and cracking and splinting is reduced. The resulting smooth lustrous surface facilitates effective maintenance.

Regular brushing and occasional washing away of leaves, soil or debris will keep the surface clean and defend against algae growth. When necessary, and if there is algae growth on the surface, use a surfactant cleaner such as the Sioo:x Maintenance Wash to remove any algae and staining.

Cleaning also gives a good opportunity to inspect the surface to see if there is any damage to the surface from operational wear such as scratching or scuffing. Minor surface damage can be repaired by applying the Sioo:x Premium Surface Protector to the affected area. Where the integrity of the surface treatment has been breached through physical damage apply Sioo:x Premium Wood Protector once to the affected area followed by the Sioo:x Premium Surface Protector. The colour of the repaired area will blend back to the surrounding timber over a short time.


Weathering is the chemical and physical change that occurs when timber is exposed to the weather. It occurs on the surface of the timber.

When timber is exposed outdoors without a protective coating, the surface undergoes rapid changes to both its appearance and its texture as a result of exposure to sunlight, particularly ultraviolet (UV) light, and rain, snow, ice and wind. When Sioo:x is applied as a protective coating the undesirable effects of weathering are mitigated and the desirable effects are replicated.

Leaching and tide marks

Wood contains a diverse range of naturally occurring chemicals which are mobile in solvents and are known as extractives. They can include tannins in oaks and thujaplicin and polyphenols in western red cedar.

The leaching of extractives may be uneven and may result in tide marks in regions of the wood where the extractives are concentrated. This can occur more often on vertical surfaces such as cladding. In areas near overhangs or areas not directly exposed to the weather, tide marks are likely to persist as it will take longer for the extractives to be leached from the surface of the timber at these locations.

If tide marks occur on Sioo:x treated timber, they are easy to remove using the Sioo:x Maintenance Wash or a common household detergent. Once water soluble extractives have fully leached, there will be no further development of tide marks.

Fungi and Algae

In the early stages with new timber, particularly the resinous timbers such as larch and cedar, extracts from the timber rise to the surface where they can attract dirt and this along with moisture can result in a food source for stain fungi to grow on the surface.


Sioo:x protects the timber from any fungal penetration and fungal decay but algae can develop on the surface in some circumstances, particularly in shaded north facing aspects and when there is a high degree of moisture and or adjacent vegetation. When this occurs, where possible, the surface should be cleaned. Over time as the timber matures the emission of extracts will cease.


Airborne fungal spores and especially mould spores are a normal component of the outdoor air. Spores are released into the environment from fungi growing on dead or decaying organic matter in the soil or elsewhere in the environment. Fungal spores can settle on surfaces and can germinate when moisture or high humidity is present. This can occur on non biocide treated timber and even with biocide treated timber as the biocide leaches or deteriorates with time. If fungal spores colonise on SiOO:X treated timber they should be cleaned away with a fungicide remover at an early stage. After removing the fungi it is recommended to apply another coat of the Surface Protector to the affected area.

Horizontal surfaces such as decking are more prone to be affected by the accumulation of dirt and need to be periodically cleaned.

Construction and Assembly   

When delivery is made to site the treated timber should be stored ready for use in a dry storage area with all packing material removed.


All cut and exposed board edges must be treated with an end-grain sealer, either using the Sioo:x End Grain Sealer or a quality proprietary product. Exposed end grains are a common source of moisture ingress.

Use stainless steel fixings.


Our main distributors Russwood and MTS have extensive experience in advising clients on material selection and careful detailing, which are key to ensuring that every project looks fantastic, and meets its performance objectives.


Timber is a biogenic material – it is produced by living organisms and it has an intimate relationship with moisture. The engineering of timber cladding facades needs to encompass a number of performance issues, and, in particular attention needs to be given to moisture movement and weathering. If in doubt professional advice should be sought.

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