Restoration and retrofit - The Hempcrete Topic: Designing and Building with Hemp-lime - page 486

and her friends just eight weeks (seven days a week) to complete the build, from starting
the demolition of the old building to moving in. Leah used a lot of volunteer labour, and
friends with relevant skills helped her out when needed. The main people involved in the
build were Leah's friend Andy, her son Liam, and his friends Dan and Luke, with plans
and elevations drawings provided by Leah's friend Tracey, in order to illustrate to the local
authority the proposed development of the building.
The disadvantage of working with hempcrete, as far as Leah is concerned, is that “you
are treading an unknown and unpredictable path, and when you phone hempcrete 'experts'
they all give you different advice, or only want to give you advice at all if you are using
their own products”. Despite this, however, and despite the experimental nature of the
build and materials used, Leah is happy that overall there have been very few problems,
and where these have occurred they have mostly been due to inexperienced builders with
too much youthful optimism about, for example, the number of fixings you need to hold
a wood wool board up. A few slight problems with the design showed up a few months
down the line: for example, a wall with spots of mould appearing on the render caused by
water wicking up into, and running down, the render (as there was insufficient roof over-
hang - with no rainwater goods - and the render had been continued down over the plinth
nearly to the ground). Leah says, “We corrected this by chopping out the render and the
hempcrete at the bottom, building up the height of the plinth slightly, and extending the
roof overhang, and we've had no problems since.”
Leah is impressed with how thermally efficient her house is. “It's boiling hot out there
today and it's lovely and cool in here. In the winter when you heat the place up and turn the
heating off it stays warm for hours and hours, because the hempcrete acts as a heat store.”
Leah has a wood burner and a gas boiler with cast-iron radiators: “I recycled the old gas
boiler that was already in the house, which in hindsight was a mistake - I think if I did it
again I'd go for underfloor heating.”
Asked about the reaction of friends, Leah says, “Everyone who comes in says it feels
amazing - we get really positive responses from everyone who visits … it's got a really
nice feeling to it - it never feels stuffy, or claustrophobic, or sweaty, or over-heated, or too
cold, or … it just feels like a living, breathing building … you can sort of tell that it's been
built with natural materials - it's just got that feel to it.”