The Smart-Timber™ system by ÖKOHAUS GER is based on factory processed and protected C24 structural timber, with defined sections and engineered mechanical connections. The load bearing structure and multilayer wall assembly are designed from the outset as parts of an integrated system, so that structural performance works together with the thermal, protective and functional performance of the home.

In Light Gauge Steel Framing (LGSF), the load bearing structure is formed from thin walled cold formed steel profiles assembled through a large number of mechanical connections, usually with self drilling screws. The sizing of the profiles and the configuration and execution of the connections are critical elements of the structural design.

In Heavy Steel Framing (HSF), the primary load bearing structure is formed from heavier steel sections connected in accordance with the structural design through bolted, screwed or welded connections. Individual sections may have greater mass and load bearing capacity than those used in LGSF, but this alone does not mean that the home as a whole achieves better technical performance. The steel load bearing structure must be combined with an appropriate wall and building envelope system that separately addresses thermal insulation, thermal bridges, moisture, fire protection and acoustic comfort.

The fundamental distinction of Smart-Timber™ lies precisely in this integrated approach. The load bearing structure, wall assembly, thermal insulation and protective layers are not treated as independent solutions, but are designed to work together as a unified home building system.

The low mass and flexibility of the Smart-Timber™ system contribute to an effective structural response to seismic loads. Proper configuration of the load bearing structure and mechanical connections allows forces to be transferred and distributed throughout the structural system.

Low weight is also an advantage of LGSF in relation to seismic inertial forces. Its overall seismic behaviour depends on the design of the thin walled members, the sizing and performance of the numerous mechanical connections and the system as a whole. In HSF, the greater mass can generate increased inertial forces during seismic excitation, while the final response depends on the structural geometry, sections, connections, lateral stability provisions and foundations. In both categories, seismic safety is determined by integrated structural and seismic design and its correct implementation.

The multilayer wall assembly of Smart-Timber™ combines structural and thermal insulation materials to effectively limit thermal bridges and energy losses. At the same time, the structural timber forming the load bearing structure has significantly lower thermal conductivity than steel.

In LGSF, the high thermal conductivity of steel makes appropriate thermal breaks and correct configuration of the insulation layers particularly important. The technical solution must address the potential for repeated steel profiles to create thermal bridges within the building envelope.

In HSF, the heavier steel sections may be fewer in number, but every point where the steel structure interrupts or penetrates the continuity of the insulation can create a significant local thermal bridge. A continuous insulation layer, suitable thermal breaks and careful detailing of the connections between the load bearing structure and the external envelope are therefore required.

The C24 structural timber used in Smart-Timber™ is not left unprotected. Before construction, it undergoes industrial preservative treatment against biological agents and is then incorporated within the protected building envelope. Moisture control is also a fundamental design consideration for the long term protection of the timber. Technical literature confirms that timber durability is linked to exposure conditions, design and, where required, appropriate preservative treatment.

In LGSF, the long term protection of thin walled steel profiles depends on suitable surface corrosion protection, maintaining its integrity at cuts and connections and controlling exposure conditions.

In HSF, protection applies to the heavier sections and to critical areas such as welds, bolted connections, column bases and points of contact with other materials. The selection and maintenance of the appropriate protection system must correspond to the exposure category of the project. This is particularly important in Cyprus, where moisture and marine salts can increase the risk of corrosion.

In Smart-Timber™, fire protection forms part of the overall wall design through appropriate layering and the use of specified fire protection materials.

In steel framing systems, steel is noncombustible, but its strength and stiffness decrease as temperature rises. In LGSF, the thin walled profiles have a large exposed surface area in relation to their mass, and their protection depends to a significant extent on the appropriate layering of the linings. In HSF, the rate of heating is influenced by the size and shape of the sections, but this does not remove the need to verify load bearing capacity under fire conditions. Both types require specialist fire design and, where specified, suitable passive fire protection.

The multilayer construction of Smart-Timber™ helps limit the transmission of noise and vibration and creates a quieter, more comfortable indoor environment.

In LGSF, repeated thin walled steel members can create paths for vibration transmission through walls and floors. In HSF, the main beams, columns and their connections can similarly transmit structure borne sound between different parts of the home. The final acoustic performance of both types is determined not only by the mass of the frame, but by the complete build up, the decoupling of surfaces, the connections and the measures used to limit structure borne sound.