Finishes for hempcrete - The Hempcrete Topic: Designing and Building with Hemp-lime - page 395

ledge to mix and use your own basic lime or clay plasters is not difficult, and there is lots
of help available, not least from your lime supplier.
Never underestimate the value of a good relationship with your supplier of lime and other
natural building products. If you plan to do a lot of this type of work, it's worth putting
some time and effort into this relationship. Don't just buy your materials from whoever is
cheapest that week; choose your supplier in terms of their locality, the types of materials
in which they specialize, and above all their knowledge of what they are selling - and then
stick with them. If you help them, they will help you, and you are likely to need their sup-
port. Some suppliers offer training courses. In some cases they may produce their own pro-
prietary plasters and will be able to advise you on specification, taking into account your
level of experience and skill, and the job at hand.
Whether you choose to mix your own plasters or buy proprietary products, it is important
that your supplier knows that hempcrete is the substrate, and understands what it is. If us-
ing a proprietary mix, check that it is suitable for use on hempcrete; if mixing your own,
ensure that you are using a well-graded aggregate (with a range of particle sizes) for max-
imum vapour permeability, and, in the case of a lime finish, that it is of suitable type for
the application. The easiest way to ensure the quality of the aggregate is to buy it direct
from specialist heritage or natural building suppliers, who normally stock a range of types
of sand and other aggregates and can discuss your specific requirements with you. Bags of
lime (usually only NHL 3.5) can sometimes be found in, or at least ordered through, your
local builders' merchants, but the staff team in these shops are unlikely to have personal
experience of using lime or be able to give advice, or at least reliable advice, about it.
Thankfully, lime plasters and mortars and other breathable building materials are available
from a growing number of specialist suppliers around the UK (see Resources for some ex-
amples). The market for these suppliers was initially builders involved in specialist herit-
age building restoration, but over recent years the market has expanded to include custom-
ers interested in low-impact, sustainable construction.
Many new suppliers have emerged to supply this market, and existing suppliers have deve-
loped their business in this direction. As a result, today you will find some suppliers who
focus more on traditional building; some on sustainable building; and, increasingly, some
who straddle both markets. Which type of supplier you choose may depend on the focus of
your particular project, since hempcrete is as likely to be used in historic refurbishment as
sustainable new build. The important thing is that you find a supplier with whom you get