Target Dry Density – 800 to 1400 Kg/m³
The construction of floors over a steel roof deck presents a unique set of challenges: managing structural load, ensuring a solid and stable walking surface, and mitigating noise transmission. While traditional concrete can be used, NanoPORE™ Advanced Lightweight Aerated Concrete (NLAC) is a superior, engineered solution that excels in this specific application.
Here’s a detailed breakdown of why NLAC is the best choice after laying the steel deck and reinforcements:
- Drastically Reduced Structural Load (Lighter in Weight)
- The Critical Issue: Steel structures are designed to be strong and efficient, but they are highly sensitive to load. The weight of a traditional concrete pour (approx. 150 lbs/cu.ft or 2400 kg/m³) imposes a significant dead load on the steel frame, columns, and foundations. This often necessitates the use of heavier and more expensive steel sections to support the weight.
- The NLAC Advantage: NLAC is typically 30% to 50% lighter than standard concrete. This dramatic reduction in dead load means the entire structural system can be optimized, leading to potential cost savings on the steel frame and foundations. It is also the safest choice for retrofitting or adding floors to existing steel structures where load capacity is a primary concern.
- Superior Sound Insulation and Acoustic Comfort
- The Problem with Steel Decks: A major drawback of steel deck construction is its propensity to transmit and amplify sound. Impact noise (footsteps, dropped items) and airborne noise easily travel through the rigid structure, creating an acoustically uncomfortable environment, especially in multi-story office or residential buildings.
- The NLAC Solution: The closed-cell, aerated structure of NLAC acts as a natural acoustic barrier. The millions of trapped air pockets effectively:
- Dampen Impact Sound: Absorbing the energy from footsteps and reducing noise transmission to the floors below.
- Block Airborne Noise: Providing a significant buffer against conversations and other ambient sounds.
This results in a quieter, more private, and productive environment, helping meet building code requirements for acoustic performance.
- A Solid, Stable, and Monolithic Floor
- Beyond “Lightweight”: The term “lightweight” should not be mistaken for “weak.” Once cured, NLAC forms a high-strength, rigid, and monolithic slab.
- Stable & Vibration-Resistant: It provides a solid, stable floor surface that minimizes the “bounce” or vibration often felt with lightweight composite decks, enhancing the feel and quality of the floor.
- Excellent Base for Finishes: This stable and level surface is ideal for the direct application of a wide range of final floor finishes, including tiles, carpet, wood, or epoxy coatings, without the risk of cracking or movement that can plague non-integrated systems.
- Additional Critical Advantages for Steel Deck Construction
- Enhanced Fire Rating: The inherent fire-resistant properties of concrete are maintained in NLAC. When poured over a steel deck, it contributes to the assembly’s fire rating, protecting the structural steel underneath from rapid heating in the event of a fire.
- Pumpable and Efficient Installation: NLAC’s flowable nature allows it to be pumped over long distances and to great heights, easily filling the entire deck area, encapsulating the reinforcement, and flowing into all the corrugations of the steel deck. This creates a perfect mechanical bond and is far faster than placing and levelling traditional concrete.
- Thermal Insulation: The same cellular structure that provides sound insulation also offers excellent thermal resistance, contributing to the building’s overall energy efficiency by reducing heat transfer through the floor slab.
