Mixing hempcrete - The Hempcrete Topic: Designing and Building with Hemp-lime - page 320

Just the right amount of water
Water can be measured into the mix in different ways, and in some cases small adjustments
may have to be made, usually by eye, to account for variations in the weather conditions or
the hemp shiv being wet. However, as a general principle, precision about the proportions
of ingredients is especially important in terms of the amount of water added. The conse-
quences of either too much or too little water can be serious.
The right consistency is not too wet and not too dry.
Not enough water
The hemp shiv arrives at the site in a dry state, and is carefully stored on-site to ensure
that it does not get wet. Failure to do this can result in it getting damp and mouldy and
beginning to rot before it can be protected by being mixed with the binder. The lime-based
binder is hydraulic, meaning that it requires water for the chemical reaction by which it
sets (see Chapter 3 ). A certain amount of binder requires a certain amount of water to al-
low it to set fully. However, because the hemp is dry, it naturally absorbs water when it
comes into contact with it, and so when the hemp and the binder are combined with water,
the two ingredients are actually in competition for the water in the mix.