In the UK, ICF homes, or to give them their full name Insulated Concrete Formwork
homes (but also often referred to as concrete insulated forms) have actually
been around since the 1970's in one form or another.
Although they are relatively new here in the UK and Ireland they're quite popular in the USA.
ICF building systems comprise of large polystyrene blocks that lock together to form a house shaped mould into which concrete is poured to form the wall structure of your ICF house.
Each polystyrene block comprises two pieces of insulation joined together by metal straps. Once assembled together with all the other ICF blocks they form an inner wall of insulation and an outer wall of insulation with a void in between where the concrete will eventually go.
When all the ICF blocks are joined together they look just like a traditional cavity wall made from polystyrene. Once assembled the walls are supported with shuttering before the void (or cavity) is filled with concrete to form the wall structure.
In order to strengthen the
polystyrene while the concrete is poured and then while it cures. Shutters are installed to brace the polystyrene as it would burst under the weight of
the concrete if left un-supported.
On completion the finished wall is virtually the opposite of a traditional block cavity wall as it has a core of concrete where the insulation would be in a traditional wall and two layers of insulation to the inside and outside where the block work would be on a traditional wall.
Traditional construction also tends to be built with lightweight materials such as breeze blocks or timber frame which have a low thermal mass allowing the temperature inside them to fluctuate more rapidly.
If you decide to build an insulated concrete form house you should take time to speak to the manufacturer. Who should in turn be able to put you in touch with experienced engineers and local builders who have built ICF homes before.
It's important to use professionals who are not only experienced and skilled at liaising with building control but also at erecting ICF building systems.