10 reasons ICF makes sense for self-builders
Chris Bates reveals how insulating concrete formwork can offer a straightforward route to self-building an energy-efficient, design-led bespoke home
Chris Bates
Built using Beco Wallform’s structural system, this contemporary scheme features a cantilevered, copper-clad upper storey. Left: A basement build by ICF Supplies, using Nudura blocks, prior to the concrete pour
Simplicity and continuity are two key ingredients if you want a straightforward project. So given that just about every self-build starts with a concrete foundation, wouldn’t it make sense to use it for the rest of a scheme? That’s where ICF, or insulating concrete formwork, comes in.
What is ICF?
The way this system is put together means it’s often referred to as LEGO for grown-ups. Fundamentally, it consists of modular, lightweight hollow blocks, which are usually made from expanded polystyrene (EPS). These interlocking forms are dry-stacked on site and reinforced with steel rebar, before concrete is poured into the cavity.
The fill is generally done in stages, floor by floor (you can go up to around 3m with each lift), but unlike other types of formwork, with ICF the blocks are retained postpour. Once the main structural work is completed, and the concrete cured, you get a strong, highly-insulated and airtight building that’s ready to finish inside and out.