Insulated Concrete Forms (ICF) are formwork blocks created from insulative materials. We prefer Durisol due to its low embodied-energy, and lack of petroleum-based compounds, compared to the common rigid-foam ICF. The blocks are first laid in place and stacked like Lego. Concrete is then poured into the spaces within the blocks to provide rigidity to the wall structure.
Advantages of ICF include good insulating properties, minimal thermal bridging, and a good air seal. An additional advantage of Durisol is the placement of the insulation completely on the outside of the concrete, allowing the concrete to function as an effective thermal and humidity mass.