Episode Details

Welcome to Where it's AT | the Architectural Technology Podcast

In this episode of 'Where it's AT' from CIAT, host Chris Halligan, a Chartered Architectural Technologist, is joined by Ian Pritchett, Innovation Director at Green Core Homes, to discuss the use of hemp in construction. They explore the historical context of hemp as a sustainable material, its benefits, the challenges of commercial application, and the development of prefabricated hempcrete panels. Ian shares insights on the material's thermal properties, breathability, and its potential to last for centuries as long as appropriate maintenance is performed. The episode also touches upon the commercial hurdles and insurance issues faced while trying to mainstream hemp-based construction.

Chris Halligan MCIAT, CEnv

Chartered Architectural Technologist (MCIAT) and Chartered Environmentalist (CEnv), with a career spanning over three decades, Chris has been involved with a wide range of architectural projects. This experience covers leading teams from inception to completion across a variety of sectors including residential, educational, commercial, leisure and institutional spheres. As well as being adept at the technical and functional resolution of buildings, Chris also specialises in Sustainable Design with a particular interest in the use and performance of building materials in respect to the environment. In this capacity he is an accomplished public speaker, presenter, guest lecturer, and advisor.

Ian Pritchett BSc(hons)

A physics graduate from Durham University. From 1987 to 2007 Ian was Managing Director of IJP Building Conservation Ltd, one of the leading conservation contractors in the UK. IJP specialise in the repair of all kinds of historic buildings including windmills and water mills. 2002 to 2013. Ian’s growing awareness of environmental issues and belief that traditional materials have an important role in the future of mainstream construction lead to the formation of Lime Technology Ltd. (in 2002), a company dedicated to pushing the use of traditional lime mortars into the new build market, as an ecological alternative to cement, by the innovative use of modern methods. 2013 to date. In 2013 Ian left Lime Technology and set up Greencore Construction Ltd, now rebranded as Greencore Homes Ltd. Ian is currently Innovation Director. Greencore is pioneering low and zero-carbon houses using its own Biond building system. This is a closed panel timber frame system insulated with Lime-Hemp and natural fibre insulation. In January 2022 M&G became a shareholder and Greencore plans to build 10,000 “better than zero-carbon” homes by 2035.

—

00:00 Introduction

00:35 Meet the Hosts: Chris Halligan MCIAT and Ian Pritchett

01:03 The History and Revival of Hemp in Construction

02:18 Modern Applications and Challenges of Hempcrete

07:04 Prefabrication: The Future of Hempcrete Construction

09:35 Sourcing and Material Composition

11:38 Thermal and Environmental Benefits of Hemp

18:34 Commercial vs. Residential Use of Hempcrete

20:43 Regulatory and Financial Hurdles

24:19 Sustainability and Longevity of Hempcrete Buildings

28:31 End of Life and Recyclability of Hemp Panels

29:34 Conclusion and Final Thoughts

—

Prefabrication solved hempcrete's commercial viability challenges

The shift from wet, on-site casting to factory-prefabricated panels was the breakthrough that made hempcrete practical for commercial construction. This eliminated weather-related delays and reduced production time from weeks to just 48 hours per panel, making it viable for projects with strict timelines and penalties.

Hempcrete offers superior thermal performance through phase change properties

The material's unique cellular structure allows moisture within the hemp to change between liquid and vapor states, absorbing and relea