The durable SOLID EXTRA loft ladder has a 46 mm thick sealed hatch. The hatch has a heat transfer coefficient of 0.85 W/m2*K. To increase safety, the SOLID EXTRA loft ladder has been fitted with a handrail for easier entry and non-slip feet. The all-metal ladder allows for a maximum load of 210 kg. The ladder structure has been powder-coated, giving it a modern look and ensuring that it will last for many years. Ud - the coefficient of the hatch centre.