Building with Hemp and Lime - a Study of the Dublin Institute of Technology

Introduction

The current unsustainability of the building industry in developed countries is contributing to reduce the overall capacity of the Earth to support life. Energy and resources are wastefully used and consumed in the sector, and there is little debate on their potential depletion. Moreover the negative effects of many synthetic mainstream construction materials on human health are often overlooked even if there is ample evidence of the related symptoms.

Unfortunately there seems to be few signs showing a change in the course of action. A conservative attitude prevails in the construction industry, and the few changes put in place are superficial and only aimed at improving the image of the industry more than trying to pursue real sustainability. Solutions already exist. It is demonstrated that the sustainable use of natural materials in construction has benefits for the human health, the economy and the environment. Lime-hemp, among the various natural building techniques, is apparently turning out to be very interesting and promising as one of the possible alternatives for the construction industry of the twenty-first century.

Lime-hemp and sustainability

The overall sustainability of lime-hemp makes it appealing from three different points of view: environmentally, economically and socially. On the environmental side, limehemp is ideally in line with The Natural Step s four sustainability principles (see paragraph 2.1.2); it reduces carbon dioxide emissions thanks to his thermal properties, and works as a carbon sink capturing carbon dioxide in the structure of buildings (see paragraph 2.6.3.3); it makes various synthetic materials redundant thus reducing dependence on fossil fuels (see paragraph 4.6.2); it is a low waste material and, at the end of the lifecycle while the lime content is fully recyclable, the hemp hurds are completely biodegradable.

On the economic side, lime-hemp is sustainable being a local produced material. It directly links agriculture and industry therefore giving back the due importance to the primary sector. It reduces dependence on importation of raw and finished construction materials. Local economy benefits because of the existence of a local lime-hemp industry and the rise in local employment is a direct consequence. Lime-hemp is also beneficial on the social side. As the local economy flourishes, i.e. appearance of a new industry and increased employment, so does the local community.

Farming is declining in the most developed countries thus hemp would give farmers an alternative crop and source of incomes. The healthy nature of lime-hemp buildings is a further benefit for the overall community.

Lime-hemp in Ireland

Ireland could be the third country in Europe, after France and the UK, where lime-hemp becomes a mainstream construction material and building method. Necessary condition is the existence of a local lime-hemp processing industry and in fact, it has emerged that a first attempt to set up the indispensable supply chain is currently taking place in the country.

There are however other barriers which are slowing down the overall mainstream process. They have been the object of the research and it has therefore been possible to identify the most important issues.

Regulatory and knowledge barriers

Among the six category of identified barriers (technical, commercial, regulatory, knowledge, psychological, and invisible) two of them, namely regulatory and knowledge, emerged as the most important. Their solution would make the wide take up of lime-hemp in the country much more likely.

On the regulatory side, the existence of an Agrément certificate would help making the biocomposite more popular among architect, builders, and providers of structural insurance, as well as reducing their lack of confidence by providing a guarantee on the reliability of lime-hemp. The lack of certification is apparently the main issue constraining the wider use of the material. On the knowledge side much has still to be done. With the exception of architects who are seemingly aware of lime-hemp and farmers who are starting to discover hemp because of its profitability and ease of cultivation; the other considered stakeholders (construction industry, builders, consumers, financial sector, and Government) generally lack awareness on it.

Support of the Government

The support of the Government is believed to be a necessary key factor in the mainstreaming of lime-hemp. The biocomposite represents a win-win-win solution for the economy, the community, and the environment. Its promotion is therefore in the interest of the public authorities. Policies like the distribution of incentives to entrepreneurs in the lime-hemp business or the provision of subsidies to farmers for the construction of hemp storage barns are the best examples of public intervention. The Government might also play an important role in increasing the overall awareness on lime-hemp.

The current absence of support from the Government is believed to be explained by its inability to perceive reality from a system perspective. Instead of looking at the core elements of a complex system, attention is often focused on single issues without paying attention at how they are actually linked to others.

Application of the research

The results and key findings of the research will hopefully be useful for those stakeholders who have some interest in the mainstreaming of lime-hemp. It is hoped the research could provide them with a clear idea of the overall background where limehemp is placed, as well as act as a support tool for any decision based on the emerging lime-hemp industry.

The research is also aimed at increasing the limited level of awareness on lime-hemp in Ireland. If applied as information tool, it could help to reduce the overall lack of knowledge, thus tackling the second most important barrier slowing down its wide take up.

The author hopes the present work might become a stepping stone for further research on the subject in Ireland. Lime-hemp deserves it and it is in the interest of the whole community that these kinds of innovations are furthered for the benefit of all.

Limitations

The main limitation of the research consists in the poor representation of some of the involved stakeholders views.

The Irish construction industry s point of view is poorly considered. As already mentioned an in-depth interview with a spokesperson from the Construction Industry Federation was initially planned as part of the methodology. Unfortunately it has not been possible to conduct the interview because of the lack of response from the organisation. All the results in which the construction industry is mentioned are however opinions of both the actual interviewees and the author.

A survey among building contractors as well as producers of material made redundant by lime-hemp would have completed the research. Unfortunately it has not been possible to carry it out because of time constraints over the project. Irish farmers are not represented properly too. A survey among ex sugar beet growers would have probably provided further evidence of what has already emerged. Again, time constraints did not permit it.

Finally, as already mentioned local production of lime has been voluntarily overlooked. Lime is already well known and it has been used for centuries in Ireland. Moreover the existence of a local lime production and market has not been regarded as a potential obstacle for the large adoption of lime-hemp. However deepening the observation of the link between lime production and lime-hemp processing would have provided further insights.

Recommendations and further research

The Government s support of the lime-hemp industry is highly recommended. The justification has been already discussed in paragraph 5.2.3 and 6.2.2. Simple public policies could consist in the distribution of subsidies to farmers for the construction of storage barns for hemp straw, or in the acceleration of the lead time in releasing licenses for growing hemp. More far-sighted policies could consist in the provision of incentives to entrepreneurs aimed at setting up new processing facilities as well as funding for scientific research on the biocomposite.

The organisation of a competition among building contractors for the construction of a number of lime-hemp building would fulfil multiple aims:

1. training: it would be an opportunity for builders to learn the necessary know-how involved in lime-hemp construction;

2. demonstration: it would create the needed momentum and help to increase the overall knowledge on the technique;

3. assessment: it would give the opportunity to carry out the required assessments for proving the properties of lime-hemp.

Further research is indeed needed. The most important and urgent at the moment is to assess the compliance of lime-hemp with the Irish building regulation aiming at the obtainment of the Agrément certificate. For the same purpose research is needed to prove the 60 years durability requirement.

Research assessing the market potential of the biocomposite is believed to be necessary too. Every single market according to the end use of lime-hemp (plastering, floors, wall infill, roof insulation) have to be carefully explored. This would avoid over (or under) estimations and improve decision-making in general.

By: Paolo Ronchetti

The entire thesis:

http://www.visionecondivisa.it/uploads/Grp/MSc_dissertation_on_lime-hemp_-_Paolo_Ronchetti.pdf