When a self-build client out near Okehampton first mentioned Nudura to us, most of the questions were about cost per square metre against a standard block-and-beam build. That’s changed this year. England’s Future Homes and Buildings Standards were published back in March and take effect on 24th March 2027, and Wales is updating its own Part L on its own timetable — so now the questions are about airtightness and running costs, not just price per block.
An ICF wall is built from hollow, interlocking Nudura forms — expanded polystyrene blocks that stack like oversized Lego — with vertical and horizontal rebar tied in as you go before the pump arrives to fill the cavity with concrete. Once it’s cured you’re left with a continuous insulated structural core in one pass, rather than blockwork, wall ties, cavity insulation and render going up as four separate trades on four separate days.
The 2021 uplift to Part L already asked for around 30% less carbon dioxide from new homes than the previous standard, and the incoming rules push further on fabric performance. A well-detailed Nudura wall can get U-values well under 0.15 W/m²K without needing a belt-and-braces cavity fill on top, which matters when Building Control on Dartmoor’s edge is checking airtightness test results as closely as the plans.
It’s not a straight swap for masonry — openings, service penetrations and the ground-floor junction still need proper structural engineering, and getting a concrete pump onto a tight rural plot near Bridgwater or into a walled garden in Wells takes as much planning as the wall build itself. But for clients chasing a Passivhaus-style spec across Devon, Cornwall and Dorset, it’s increasingly the starting point rather than the exception.
If you’re planning a self-build or extension anywhere across Devon, Cornwall, Dorset or Bristol and want to know whether ICF stacks up for your plot, The Fell Partnership’s team can talk you through it — get in touch via thefellpartnership.co.uk.
