Compare
Two options. One context. A decision.
Set the two candidates and the climate they must survive. The table is data; the recommendation is reasoned.
| Attribute | Norway Spruce | Western Red Cedar |
|---|---|---|
| Latin name | Picea abies | Thuja plicata |
| Density | 450 kg/m³ | 370 kg/m³ |
| Bending strength | 80 N/mm² | 68 N/mm² |
| Dimensional stability | Moderate | Very high |
| Durability | DC 4 (slightly durable) | DC 2 (durable) |
| Service life | 10–20 yrs treated, 5–10 untreated exposed | 40–60 yrs façade |
| Colour ageing | Yellow-warm → grey-silver in 18–36 months when exposed | Red-brown → soft silver-grey in 12–24 months |
| Fire | Euroclass D-s2,d0 · charring 0.65 mm/min | Euroclass D-s2,d0 · charring 0.67 mm/min |
| Carbon stored | 0.78 t CO₂e/m³ | 0.72 t CO₂e/m³ |
| Cost index | 38 | 100 |
Climate context: Coastal Scotland · Cfb — temperate oceanic · Wind-driven rain and chloride load dominate. Biological growth on north elevations within 24 months.