This article was originally post here: Retrofitting stick frame houses with hempcrete, a super sustainable solution.
Here I note about Hempcrete for existing structures and retrofitting stick frame houses (the video is of a house similar to a Queenslander) with hempcrete. Considering sustainability, and the existential crisis of climate change, this is a very important project.
Hempcrete for existing structures
The main components of the house, the footings, structural framework and roof are all in good condition being structurally sound and of a good size and layout for a family to live and thrive in. But as with many houses built in Australia there was little consideration of thermally controlling the internal areas considering fairly mild weather, cheap power, lax building standards in regards to the thermal envelope (insulation and sealing) and the idea that building was cheap so ‘lets knock up some houses now for people to live in an we’ll deal with anything later’.
This means there are 1000’s of houses around Australia with little insulation or proper sealing or other passive design principals regarding shading by eaves and thermal mass. Which means it’s hard to maintain the temperature at a level comfortable for humans in both summer and winter. In summer we crank the aircon and in winter we turn on a few bar heaters and maybe put on a jumper.
A good article about this can be found here. https://www.theguardian.com/commentis…
So what makes this a very important project is that we are using a fantastic framework for a house, and therefore not doing a knock down and re build, so limited new materials need to go into making this house good for another 100 or many more years.
Some internal walls were re arranged to allow for a more open plan style living. The wiring was completely re-done for safety reasons and to bring it inline with modern expectations. Some plumbing was done regarding placement of the kitchen. Upgraded flooring and roofing, including insulation is part of the project. A deck facing the Western view with an awning to protect from the harsh summer sun will complete an indoor/outdoor forward lifestyle house.
“Thats what makes this project very important for everyone on this planet”
Jeremy Thomas | Building Designer
Additionally the experienced and eco conscious owner builder opted for up-cycled doors and windows framed by locally sourced timber. The hemp bast comes from just a few hundred kilometres away (close by Australian standards). The sand and water from the region. The lime binder I am not sure about but I intend to find out!
Hemp grows quickly whilst sucking in CO2. When turned into hempcrete the drying and curing process continues to suck in CO2. And then the hempcrete slowly petrifies to stone over many years so gets harder and harder all whilst sucking in CO2 from the atmosphere. This makes hempcrete a carbon negative building material.
Combine a carbon negative building material into a house that is already built and you have a carbon negative family home that is super well insulated so will take very little external power to heat and cool the spaces.
Thats what makes this project very important for everyone on this planet.
We can grown the hemp and use it to thermally insulate the 1000s (probably 100s of 1000s) of badly built houses around Australia limiting our need for new materials and fossil fuel power needed to thermally control the internal space of the house.
Take a peek and find our why retrofitting stick frame houses with hempcrete is so important. Feel free to reach out to us with any comments and questions.
Contact us to discuss retrofitting your stick frame clad house.
This article was originally post here: Retrofitting stick frame houses with hempcrete, a super sustainable solution.
Why hempcrete an internal wall? What thermal advantage comes from doing that?
Hi Peter,
The owner builder decided to go for internal hempcrete walls for several reasons. The main one was that the site was not far from a highway and the more hempcrete walls the more the sound from the HY was dampened. If you look at the Shed to Hempcrete home video it’s amazing (I suppose more so when you are on site) to notice the difference in sound when outside the structure as compared to when inside. He did no windows on the HY facing wall and it’s virtually silent in his home.
Another reason was to lock in the carbon into the walls. He also like the aesthetic of the hempcrete. And All the bedrooms are also acoustically separated by the hempcrete walls!
https://www.youtube.com/watch?v=C64yevoQncc
Hempcrete has a fantastic R-value as it has all the air in it both in a casting and molecular level.
The owner builder went for internal hempcrete walls for several reasons.
– aesthetic so the house has a similar look and feel
– external sound insulation – the house is located next to the highway and the living areas are now behind 2 hempcrete walls making the HW virtually in audible. Also great for internal sound
– internal sound insulation – if you are in a room with the doors closed sound from the activities in the rest of the house wold be severely dampened.
– general sound treatment -0 if you ever been into a recording studio there is a sense of calm due to the sound treated walls. Same happens with hempcrete walls.
Where is the internal thermal mass to be found?
Is Hempcrete ceiling an option?
More a roofing insulation option. A wood panel lining board is used and the hempcrete filled on top. As it doesn’t have to ‘cast/set’ as much is usually a different mix ie less binder more hemp hurd.