Does anyone know anything about Insulated Concrete Wall Systems? Also known as ICF’s. they are supposed to be quicker and cheaper to build with compared with traditional blocks. And when built give better heat and sound insulation. As far as I know they work as follows: The builder puts the polystyrene cavity wall sections in place and then pours concrete into the gap between the outer and inner wall sections. We are thinking of going with this for our new house. Has anyone any experience of building with it? Is it really cheaper? The company we have heard about are called Reward Structure Ltd.