Lightweight Insulating Concrete (LWIC) Roof Decks are composite systems cast over galvanized metal decks, structural concrete, wood decks, or existing roof systems using LWIC and Expanded Polystyrene (EPS). LWIC slurry contains Portland cement, water, and preformed foam. There are two predominant types of LWIC: Cellular or Aggregate. LWIC encapsulates Expanded Polystyrene (EPS) insulation boards which are laid out in a stepped pattern custom-tailored to each job to achieve the specified slope and R-value (thermal resistance). The LWIC composite system provides a surface to attach the new roof membrane. No cover boards are required or vapor barriers. The LWIC composite system can provide FM and UL ratings, both wind and fire. LWIC’s additional benefit is that it greatly reduces any air infiltration and creates a heat sink that locks in the R-Value and reduces membrane thermal shock to prolong the life of the new roof membrane.

The most common alternative to structural sloping in today’s market is using tapered polyisocyanurate. Traditional roof insulation systems such as polyisocyanurate are not as durable, wind resistant, or cost-effective over the long-term as LWIC.

• Durable: Encapsulating Lightweight Insulating Concrete preserves R-value of polystyrene insulation as well as creates permanent slope. Other methods use costly cover board to hide the shrinkage of polyisocyanurate over time. You will need to replace polyisocyanurate every time you replace your roofing due to age or failure while a cellular concrete substrate lasts the life of the building.
• Wind-resistant: LWIC systems are known for their strong performance history of resistance to high wind loads. The concrete slurry coat bonds the system to the structural substrate, helping to provide high wind load resistance.
• Cost-effective: EPS boards can be cut up to thicknesses in excess of 48”, meaning you only need one layer of insulation to meet your desired slope. Other materials require multiple layers of insulation to achieve desired slope, slowing production and increasing costs with large amounts of expensive adhesive or extra-long specialty fasteners.