Sustainable construction and modular timber homes are transforming the landscape of structural engineering in Portugal. In a sector where off-site execution speed, quality control, and factory efficiency are absolute priorities, traditional connection methods are giving way to advanced engineering solutions.
Although nails and threaded rods have been the standard for years, structural screws are now the critical component to ensure efficiency on the production line and absolute safety during module transport. When the focus is maximum resistance and technical compliance, European leading brands like Klimas Wkręt-met lead this transition.
The Limits of Traditional Connections under Eurocode 5
The design of timber structures in Portugal is strictly regulated by Eurocode 5 (EN 1995-1-1). This standard requires strict analyses of load capacity and joint deformation. This is where legacy fasteners show their weaknesses in the modular model:
- Nails and the Risk of Backout: Conventional nails do not offer the necessary design resistance against the dynamic vibrations that modules experience during road transport to the job site. The risk of nail backout or loosening compromises the millimeter-level tolerances required in structural panels such as OSB or glued laminated timber (CLT/KVH).
- Threaded Rods and Through-Bolts: These require perfectly aligned pre-drilling. In a fast-paced factory environment, the time spent measuring, drilling, aligning elements, and tightening nuts creates severe bottlenecks on the assembly line, raising the unit labor cost.
The Science Behind Klimas Structural Screws
Klimas construction screws, such as the washer head (WKCP) or countersunk head (WKCS) ranges, were specifically designed to meet the structural demands of engineered wood. Their technical superiority is based on innovations that optimize material behavior:
- Special Drill Point and Double Thread: The innovative design of the milled point on Klimas screws reduces screwing resistance by up to 20%. This allows direct insertion without pre-drilling, even in high-density timbers, eliminating the risk of structural cracks in the wood.
- Active Pulling Effect (Rope Effect): Thanks to the partial or double-thread geometry, the screw actively pulls the wooden elements against each other with massive compression force, ensuring perfectly airtight joints.
- Full European Certification: All Klimas structural screws hold the prestigious European Technical Assessment (ETA-18/0817), providing design engineers with the exact withdrawal and shear resistance values needed for calculation software.
- SQ Ceramic Coating: In addition to standard white zinc plating, Klimas offers the SQ protective ceramic coating (Class 4). This treatment ensures exceptional corrosion resistance in demanding atmospheres (Service Classes 1, 2, and 3), preventing chemical degradation of the wood around the fastener.
Comparative Analysis: Impact on Execution Time
The choice of fastener directly dictates project profitability. The table below compares the estimated average application and preparation time between different connection systems:
| Connection Method | Pre-Drilling Required? | Avg. Application Time (per point) | Vibration Resistance (Transport) | Flexibility / Reversibility |
|---|---|---|---|---|
| Klimas Structural Screw (Torx) | No(Self-drilling) | 3 to 5 seconds | Excellent(Deep thread) | High(Removable without damage) |
| Threaded Rod with Nuts | Yes (Double drilling + Alignment) | 45 to 60 seconds | High (Requires a lock nut) | Medium (Slow process) |
| Pneumatic Threaded Nail | No | 1 to 2 seconds | Low/Medium (Risk of recoil) | None (Destroys the fiber when removed) |
Optimization from Factory to Construction Site
- On the Production Line: The use of the Torx (TX) drive in Klimas screws eliminates tool slippage (cam-out), allowing operators to work continuously with impact drivers. Because the tightening is instantaneous and pulls materials together autonomously, reliance on heavy mechanical presses is eliminated, reducing cycle time per factory station.
- At the Assembly Site (On-Site): When volumetric modules arrive on the field, stitching them together must be immediate to avoid exposing the building to bad weather. Klimas WKCP washer head screws distribute the fastening load over a wide area, allowing adjacent module walls to be joined in just a few minutes with total structural safety.
Reverse Engineering and Circular Economy
The ecological footprint of modular timber homes does not end with the choice of raw material. The concept of sustainable construction requires planning for the end of the building's lifecycle.
Klimas structural screws support the circular economy thanks to their total reversibility. They can be cleanly unscrewed, keeping CLT beams or panels intact for future reuse or reconversion. This reduces job site waste and raises the residual value of modular real estate assets.
