Hemp demonstration action Tiverton Campus 26th February 2015

Wooden frames were built prior to the training.

Ordinarily, the frame and hemp would be built on

a stone, brick or blockwork plinth to prevent

water ingress / damp rising. Due to the time of

year and the weather, and this being a training

exercise, we decided just to use wooden frames.

They were designed to be free standing so that

they could be reused for future training.

Wood used for the frames is 4x2. The frames are

2m long x 1m high, with 400mm spacing. This

replicated the size of wood and spacing that

would be needed in an actual build.

Fixing horizontal battening

Side panels cut to 200mm to allow

an overall depth of 300mm. The

horizontal battening placed along

the length across the main frame

is placed at approximately 600mm

spacing. This acts as a key which

provides extra strength to the

hemp wall. Without this, there is

no structural connection to the

timber frame.

Fixing the shuttering

Guide screws (deck screws) are placed along

with wooden spacers (wooden spacers are

not screwed in but made so they push firmly

into place). They act as support for the

shuttering and for setting accurate spacing

to allow for the overall 300mm.

Wooden spacers are removed once the

hempcrete reaches their level. Leaving the

Screws in place until shuttering is moved.

Explaining how the framing and shuttering works

Screws must not be left in as any metal fixings

left exposed to hemp and lime mix will rot. Any

metal fixing that will have contact should be

stainless steel.

Filling the pan mixer. Mix is 1 bag of hemp to two

bags of lime binder and approximately 60 litres of

water.

The hempcrete mixed ready

for use.

Pouring the hemp mix into the shuttering.

Spreading evenly and lightly tamping

down withpoles made by the participants

from the battening. The hemp must not

be pressed down with too much pressure

as removing to much air will affect how

thermally efficient it is.

Removing the shuttering to

reveal the finished wall

Hempcrete Wall – the finished product