TG-I Spec Sheet
Thermosticks
Technical Specification Sheet
Technical Specification Sheet
Profile Code · TG-I
Rev. 01 · 2026
Rev. 01 · 2026
TG-I
Square-edge tongue & groove - shallow shadow line with 4° bevel reveal
Profile cross-section
TG-I · Top assembly shows two TG-I boards joined (bottom pair)
Material options
| Available species | Pine Cladding 3/4" · Radiata Cladding · Ayous Cladding |
| Treatment standard | International ThermoWood® (212°C, heat & steam only) |
| Durability | Class 1 · 25+ year rot resistance |
| Moisture at shipping | 4-7% |
| Dimensional stability | 50-90% reduction in swelling vs untreated |
Performance
| Thermal conductivity | 0.09 W/mK (approx. 20% lower than untreated) |
| Biological resistance | Fungi, mold, wood-destroying insects |
| VOC emissions | Zero - no chemical preservatives |
| Fire rating (untreated) | Euroclass D-s2,d0 - FR treatment available |
Installation
| Orientation | Vertical or horizontal |
| Fixing method | Face screw through tongue or hidden nail (HN variant) |
| Fasteners / intersection | 1 per batten intersection (face < 5.5") |
| Fastener type | Stainless steel AISI 304 self-drilling screws, or 16 ga stainless finish nails |
| Min battens per board | 3 |
| Batten spacing | Max 24" on center |
| Air cavity (rainscreen) | Minimum 1" behind board |
| Top edge clearance | Min 3/4" to eaves, flashings |
| Bottom edge clearance | Min 12" to grade; 8" over gravel |
| Available lengths | 10, 12, 14, 16 ft (ships mixed) |
Sustainability
| Sourcing | Responsibly managed Nordic forests · FSC on request |
| Treatment | Chemical-free thermal modification |
| End of life | Compostable; biomass energy recovery |
| Carbon storage | ~0.9 tonnes CO2‚ per cubic meter, lifetime |
Weathering & Finish
Thermowood weathers to silver-grey over 1-3 years if left untreated. For accelerated, uniform silvering: Valhalla Lifetime Wood Sealer. To preserve original brown: PPG Proluxe (2-3 year recoat cycle). Both available in-house at $1/linear foot.