Variations on the hemp–lime mix - The Hempcrete Topic: Designing and Building with Hemp-lime - page 119

hempcrete. The fact that hempcrete has been able to progress rapidly to the current level
of demand in the UK market we owe principally to the manufacturers of proprietary bind-
ers; especially to Lhoist and Lime Technology for their development of the Tradical ® HB
binder in the UK.
It is fair to say, however, that many in the industry see proprietary hempcrete-specific bind-
ers as something of a double-edged sword.
On the one hand, companies have invested time and money over the last decade or so into
developing and researching proprietary binder products and promoting hempcrete. As a
result of this development work, a huge variety of hempcrete buildings now stand across
the UK as testament to the potential of the material. On the other hand, the drive to develop
these materials is, of course, underpinned by the need to sell a product. The commercial
and competitive aspect leads to a number of problems from the point of view of the devel-
oping industry, and the contractor. For example, it means that while a lot of commercially
funded research is carried out into proprietary materials, the results are not always shared
across the industry as a whole. Nor are results always directly comparable with other stud-
ies, since differences in the materials used often make comparisons difficult.
Another issue arises from the fact that hempcrete construction requires specific skills and
knowledge not currently found widely across the construction industry. The success of a
hempcrete build, unless the 'work-around' of using pre-cast panels or blocks is employed,
is highly dependent on the level of competence of the contractor. Because of this, some
manufacturers and suppliers have at times, surprising though it may seem, appeared re-
luctant to allow their product to be used by anyone who cannot demonstrate the requisite
knowledge. Admittedly, building with hempcrete is certainly more complicated than open-
ing a bag of cement, mixing in sand at 4:1 and wetting it up to the desired consistency. But
we would hope that the answer to the problem of the specific skills not yet being common
in the construction industry will be in the training of the workforce rather than the restric-
tion of access to materials.