Roof Assembly

The roof is finished in durable Coloursteel with a roofing wrap beneath it. Under the wrap, 6 × 2 framing provides structure and depth for natural wool insulation. Inside, a tongue-and-groove poplar ceiling completes the assembly, creating a warm, breathable interior surface that allows moisture to disperse naturally while retaining heat.

Wall Assembly

Exterior walls are framed with Douglas fir and insulated with Terra Lana sheep’s wool. The vapour-open system allows moisture to move through the structure rather than trapping it, significantly reducing the risk of condensation. Redwood and corrugated-iron cladding protect the outer surface, while the interior walls are finished in low-VOC plywood coated with mineral-based paint.

Why Wool?

Terra Lana wool insulation is hygroscopic, meaning it can absorb and release water vapour. This natural phenomenon, unique to wool, distinguishes it from synthetic insulation and means it excels in managing moisture while maintaining thermal performance.

Floor Assembly

The floor begins with the galvanised trailer base, overlaid with 6 × 2 framing and solid gum flooring boards. Between the joists sits Terra Lana wool insulation, providing both thermal and acoustic comfort. The combination of natural materials and open diffusion paths and solid timber helps the floor remain dry, warm, and well-ventilated.

Wall Wrap System

Between the cladding and the framing sits the DriStud wall wrap — a flexible, non-woven fabric designed as both a moisture and air-control layer. It resists water penetration while allowing vapour to escape, helping regulate humidity inside the walls.

DriStud wall wrap is CodeMark-certified and engineered for high performance:

• Highly resistant to moisture and UV exposure (up to 90 days)

• Effective as an air-control layer, limiting draughts and energy loss

• Fire-retardant and designed for long-term resilience in New Zealand conditions

This layered wall system — from the breathable wrap to the wool insulation and natural finishes — works together to maintain balanced indoor humidity and prevent the damp conditions where mould thrives.

Overall Performance

The result is a naturally regulated microclimate: warm in winter, cool in summer, and continuously dry. Each component contributes to humidity balance and air purity, supporting the health of those with environmental sensitivities or anyone seeking a truly healthy home.