SSB Deep Charred Larch Treated - NAGASAKI

Deep Charred Larch Cladding UK – Yakisugi Shou Sugi Ban | NAGASAKI

NAGASAKI is the most dramatic and authentic finish in our charred timber cladding range — deep charred Siberian Larch with the full surface texture of the burn retained, treated and sealed without wire-brushing. This is the finish that most closely references the original Japanese yakisugi tradition — where timber is charred intensely, and the resulting carbon surface is preserved as it is, in its most raw and authentic form, rather than refined or smoothed back.

The deep charring process burns the Siberian Larch surface more intensely and for longer than a standard char, producing the distinctive alligator-skin texture that defines this finish. Deep ridges of carbon rise from the board face, dark grain channels cut between them, and the natural tonal variation of the char — near-black at the peaks, dark grey in the valleys — creates a surface that changes character through the day as light rakes across the boards at different angles. No two boards are identical. The natural variation between them is not a quality control issue — it is the defining characteristic of the finish, and exactly what high-end architectural practice values about it.

Siberian Larch is the ideal base species for deep charring. Its natural resin channels, tight ring structure, and variable density across the board width respond to an intense char with a more pronounced and varied alligator-skin texture than spruce could produce. The grain asserts itself through the carbon layer, giving each board depth and individual character. For the same level of charring on spruce, the texture would be flatter and more uniform — technically correct but visually less compelling. On larch, the deep char is a genuinely exceptional material.

What Deep Charred Means for Performance

Beyond the visual impact, the deep charring process delivers measurable performance benefits. The more intense burn carbonises the timber surface to a greater depth than a standard char, creating a thicker carbon layer that provides improved resistance to moisture absorption and surface weathering. The carbon surface is chemically stable, naturally resistant to fungal attack, and does not require the preservative treatment that untreated softwood cladding needs to perform in UK outdoor conditions.

The treated and sealed finish applied over the deep char stabilises the carbon layer, reduces surface transfer on contact, and provides additional UV protection to slow the natural lightening process that all charred timber undergoes over time. The result is a deep charred cladding system that is genuinely low maintenance in full UK outdoor exposure — performing year after year without the retreatment schedule that painted softwood demands.

Why Specify NAGASAKI

NAGASAKI is specified for projects where material authenticity and bold surface character are central to the design intent. Feature elevations on contemporary houses, statement façades on commercial buildings, barn conversions where the drama of a deep char sits naturally in the agricultural landscape, garden structures where the textured black surface becomes a design element in its own right — these are the contexts where NAGASAKI is the right choice and a brushed or stained finish would understate the intention.

Compared to the brushed black finishes in the range, NAGASAKI is emphatically not a controlled, refined product — and that is precisely its value. Where KOBE or BEPPU deliver a consistent, architectural black, NAGASAKI delivers drama, texture, and the unmistakable presence of a material that has genuinely been transformed by fire.

Profiles and Dimensions

NAGASAKI is available across the full range of cladding profiles in 20mm and 21mm thickness, widths of 90mm, 120mm, and 140mm, and lengths from 2000mm to 6000mm. Profiles include Batten PAR, Half Lap, Shadow Gap, Shadow Gap V Joint, Tongue and Groove V Joint, Tongue and Groove V Joint Extra, Tongue and Groove V Joint Secret Fix, Rainscreen, and Rainscreen TIGA. Bespoke sizes and profiles can be made to order. Download the full profile schedule (PDF) for cross-section drawings and connection details.

Installation Guidelines

Install as part of a ventilated rainscreen façade system with minimum 25mm clear cavity, breathable membrane, and minimum 150mm ground clearance. Use stainless steel fixings throughout — galvanised or zinc-plated fixings will corrode over time in contact with the charred surface. Handle boards with gloves during installation as the deep char surface will transfer carbon before the treatment seal is fully cured. Seal all cut ends with a compatible exterior end-grain treatment before installation. Ensure correct detailing at all abutments, sills, and reveals to maintain cavity ventilation and prevent moisture trapping at junctions. Where reaction-to-fire performance is required, NAGASAKI can be supplied with fire-retardant treatment.

Frequently Asked Questions