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ThermoWood decking boards are a stable, low-maintenance option for outdoor decking projects, including garden decking, terraces, patios and modern external living spaces. Manufactured from thermally modified timber, ThermoWood offers improved dimensional stability and reduced moisture movement compared with standard untreated softwood decking.
This category includes ThermoWood decking boards in smooth, grooved and brushed profiles, including boards designed for concealed installation with BROfix hidden decking fasteners. Secret fix decking creates a cleaner surface by reducing visible face screws, giving the finished deck a more contemporary appearance.
Available options include ThermoWood secret fix decking boards grooved 26×117mm, ThermoWood secret fix decking boards smooth 26×140mm and ThermoWood secret fix decking boards brushed 26×140mm.
ThermoWood decking is suitable where improved stability, reduced movement and a clean modern finish are important. It sits between standard softwood decking and denser hardwood decking, offering a practical balance of performance, appearance and maintenance requirements.
For alternative timber decking options, view our Siberian larch decking or browse the full timber decking boards range.
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Timber cladding performs best when designed as a ventilated rainscreen system rather than simply fixed directly to a wall. A drained and ventilated cavity helps manage moisture and improves long-term performance in UK weather conditions. Species choice then becomes a balance between dimensional stability, durability class and surface behaviour over time. ThermoWood cladding (Thermo Pine / Thermopine) is selected for enhanced stability and reduced movement. Siberian Larch cladding offers natural durability and strong grain character. Shou Sugi Ban wood (technique), often referred to as charred timber or burnt Japanese wood, provides a surface-stabilised architectural finish with distinct visual depth. Nordic Spruce cladding is a consistent softwood solution commonly specified for coated or treated façade systems. Where reaction-to-fire performance is part of the specification, review fire rated cladding options early, as Euroclass performance depends on the full wall build-up and treatment process. For broader façade detailing and installation context, see The Ultimate Guide to Timber Cladding in the UK.
| Feature | ThermoWood | Siberian Larch | Shou Sugi Ban (Charred Timber) | Nordic Spruce |
|---|---|---|---|---|
| Dimensional stability | High (thermally modified) | Moderate | High (surface-stabilised) | Moderate |
| Typical durability (EN 350) | Class 2–3 | Class 3 | Improved surface durability | Class 4–5 (untreated) |
| Moisture movement | Reduced | Medium | Reduced | Higher than modified timber |
| Fire treatment options | Available | Available | Available | Available |
| Typical applications | Modern façades, battens | Rainscreen, mixed-use builds | Feature elevations, architectural façades | Coated façade systems |
ThermoWood cladding is thermally modified to reduce moisture movement and improve dimensional stability. Siberian Larch cladding relies on its natural durability and dense grain structure. ThermoWood typically offers lower movement risk, while Larch provides a more pronounced natural character.
Shou Sugi Ban wood, also known as charred timber or burnt Japanese wood, forms a carbonised surface layer. Depending on the finish level (brushed, sealed or stained), periodic inspection is recommended. Sealed systems require maintenance similar to other coated cladding systems.
Timber cladding can be supplied with fire-retardant treatment to achieve improved European reaction-to-fire classifications. The final Euroclass rating depends on the species, treatment process and complete wall build-up. Always confirm the required classification with building control before specification.
Service life depends on species, detailing and exposure. Thermally modified timber and naturally durable species such as Siberian Larch typically provide long above-ground service life when installed as a ventilated rainscreen system with correct ground clearance.
Yes. All exterior timber, including ThermoWood, Larch and Nordic Spruce, will gradually weather to a silver-grey tone if left untreated. This colour change does not reduce structural performance and can be managed with UV-protective coatings if colour retention is required.