| Traditional solid-log wall | Horizontally stacked solid softwood logs, commonly around 180–240 mm thick | Usually no separate cavity insulation; performance relies on timber mass, log thickness, and sealed joints | Not applicable as a separate layer; additional internal or external insulation may be required in cold climates | Approximately 0.35–0.60 W/m²K, depending on log profile, timber species, joints, and moisture content | ≤ 1.5 ACH50 is a practical design target when joints and penetrations are carefully sealed | ★★★★☆ Highest at log corners, junctions, and settlement points | Moderate; can be improved substantially with extra insulation, high-performance windows, and controlled ventilation | Exterior staining or protective coating is typically needed at intervals determined by exposure and climate; logs must be protected from persistent moisture | Traditional appearance, moderate climates, and projects where visible timber walls are a priority |
| Post-and-beam timber frame | Engineered or solid timber posts and beams with non-structural insulated wall panels | Mineral wool, wood-fibre, cellulose, or rigid insulation installed between and/or outside the frame | Approximately 160–300 mm, depending on climate and target performance | Approximately 0.15–0.25 W/m²K with a continuous insulation layer and carefully designed framing | ≤ 1.0 ACH50; ≤ 0.6 ACH50 is a strong low-energy target | ★★★☆☆ Reduced by continuous exterior insulation and properly detailed connections | High; the system allows thick insulation, efficient service cavities, and flexible window placement | Exposed timber requires periodic inspection and protection; concealed structural timber must remain dry | Modern open-plan cabins, large glazed elevations, and projects requiring flexible architectural design |
| Timber-frame panel system | Light timber studs with structural sheathing and internal or external finish layers | Mineral wool, cellulose, wood-fibre, or blown-in insulation with an airtight membrane | Approximately 200–350 mm, including service cavities where required | Approximately 0.12–0.22 W/m²K when thermal bridging through studs is included in the calculation | ≤ 0.6 ACH50 is achievable with a continuous airtight layer and tested workmanship | ★★★☆☆ Studs, corners, floor junctions, and window reveals require careful detailing | Very high; suitable for low-energy or near-zero-energy designs when combined with efficient services | Low exterior maintenance when protected with durable cladding; moisture control and ventilation of cavities are essential | Cold or mixed climates, rapid construction, and cabins with strong energy-performance targets |
| Structural insulated panel system | Factory-made panels consisting of rigid insulation between structural facing boards | Expanded polystyrene, polyurethane, polyisocyanurate, or mineral-fibre cores, depending on the panel specification | Approximately 120–250 mm | Approximately 0.12–0.22 W/m²K, subject to panel thickness, joints, framing, and penetrations | ≤ 0.6 ACH50 is commonly targeted because panel joints can form a continuous airtight layer when sealed correctly | ★★☆☆☆ Generally low across the panel field; joints, corners, openings, and service penetrations remain critical | Very high; high insulation levels and prefabrication can reduce heat loss and construction time | Protect panel edges and facings from water; modifications after manufacture must not compromise structural or airtight layers | Fast-build cabins, remote sites, and compact designs requiring predictable thermal performance |
| Hybrid log-and-frame system | Visible solid-log sections combined with insulated timber-frame or panel sections | Additional insulation behind selected log walls, plus mineral wool, cellulose, wood-fibre, or rigid insulation in framed areas | Approximately 100–300 mm in insulated sections; log thickness varies by design | Approximately 0.18–0.35 W/m²K, depending on the proportion of solid-log wall and the junction details | ≤ 1.0 ACH50; lower values are possible with continuous membranes and tested sealing details | ★★★★☆ Different wall systems create junctions that require careful thermal and moisture design | High when solid-log areas are limited and the framed envelope provides continuous insulation | Visible logs need regular inspection and weather protection; transitions between systems must be monitored for movement and moisture | Projects seeking a modern energy envelope with selected traditional log features |