Variations on the hemp–lime mix - The Hempcrete Topic: Designing and Building with Hemp-lime - page 121

information, so that builders know whether a particular hemp shiv is suitable for use with
a particular binder in a given application, as in the hypothetical example shown in the table
below.
The UK hempcrete market is still some way from such a level of cooperation and flexib-
ility, but it is to be hoped that as the market continues to increase and the marketplace for
binders and shiv suppliers opens up, a time will come when UK builders have access to a
similar level of information about the products available.
Variations for different applications
The ratios of hemp:binder:water required when mixing hempcrete vary slightly depending
on which binder is being used, so the manufacturer's guidelines should always be fol-
lowed. It is important to adhere to the exact ratios, and mixing instructions, because having
the right proportions of binder, hemp and water is critical in ensuring that the binder has
enough water to set it, despite the tendency of the dry hemp shiv to 'compete' for the water
in the mix. This concept is discussed in more detail in Chapters 15 and 16 .
Example of flexible product testing regime carried out for the French
market
The 'standard' hempcrete mix can, however, be varied slightly in the proportion of binder
to hemp shiv, as advised by the binder manufacturer, in order to produce hempcrete that is
more suitable for a particular application. The mix ratio required to make hempcrete for a
wall is usually seen as the standard mix of a binder manufacturer.
Increasing the amount of binder for the same amount of hemp shiv produces a higher-dens-
ity mix, with greater structural integrity and thermal mass but reduced insulation value: