The owners of a HempCrete house in Witchcliffe, in the Margaret River region in WA, had never heard of the building material until their daughter went to a talk about it. Now they said they would always build another hemp house with Hemp Homes Australia.
"We love our house - Sativa Sanctuary. It was grown in 14 weeks, and if ever we want to demolish it (never) we can push it straight into the ground. Hempcrete is good for the body and good for the planet," said owner Andrea Beck.
"We wanted to build as environmentally friendly as possible and the material ticked all the boxes. The material is termite resistant, breathable, has thermal mass properties, very good acoustic values and is fire retardant," she said.
Built by Hemp Homes Australia using HempCrete, the interior walls have been left natural inside and exterior is lime rendered using a natural turmeric oxide. This means no paint or chemicals.
"The walls are all handmade and hence have individual striations, which are very interesting and beautiful. We like the artistic approach and experimented with coloured mineral oxides from "Bauwerk" Fremantle. You can see the results in our entrance or behind the fireplace in our living room," Andrea said.
Further economic benefits come from the double-glazed windows.
Andrea and Holger Butenschon are originally from Germany and grew up with UPVC double glazed windows, so it was a priority for their house.
"Our builder was sceptical about the windows and felt is was an overkill. We convinced him that the house will be even warmer in winter and cooler in summer with these windows. Needless to say that Gary is now a converted believer in double glazed windows," Andrea said.
Even with the windows, Andrea and Holger are impressed with the temperature inside the home.
"We were a bit sceptical, but our first winter in our beautiful home has shown that the temperature in the house at night does not fall below 17, and that's without heating."
Holger is also impressed with the acoustics.
"My husband is a bit of a music buff. He took his speakers to the house to test the acoustic. There are no reflections of the walls and the sound is incredible. His words, not mine," she said.
Building with hemp does have its challenges though. Andrea said the electrical and plumbing plan had to be spot on, as the walls can not be chased open after completion. Also, the location of the stud walls needed to be recorded to be able to hang heavier items, as hemp walls are not loadbearing.
"We took pictures with measurements of every wall prior being covered with hempcrete," she said.
During the build, the walls must not dry too quickly otherwise they will crack, so timing the build is important. This house was built during summer so the walls had to be sprayed with water every day and covered with hessian material for the six weeks it took to build the walls.
Andrea said that are a few of different hempcretes on the market.
"Imported hempcrete is darker than the local sourced. We preferred the lighter colours, plus wanted to support the local Australian hemp industry. We got our hempcrete from NSW," she said.
She also said it was important to stick to the recipe when mixing the materials.
"It's best to have the same person mixing all the time. And choose an experienced builder who has done it before. Let the builder decide on his trades people as they have the experience as well."
You can visit Sativa Sanctuary as part of Sustainable House Day on September 15. Sustainable House Day gives visitors a chance to inspect houses that have been designed, built or renovated with sustainability in mind as well as the opportunity to talk to owners and receive unbiased advice. Visit sustainablehouseday.com