Im going to use this thread as a way to keep notes on and share results from a new experimental IWI system that follows the same general “insulated render” formula as other systems such as hemp-lime, cork-lime and perlite-lime, however the primary insulating aggregate added to the lime binder will be Biochar instead of hemp, cork or perlite.
I’ve found one example of a similar thing being done by the Ithaka Institute, only they used clay as the binder instead of lime.
The attributes of Biochar that indicate that it may have great value as an insulating material are:
1. Its low density / high porosity (google images of Biochar under microscope) which should trap lots of air and make a good insulation.
2. Its stability / longevity (Biochar is said to last for THOUSANDS of years even when buried in moist, life-rich soils). I’m hoping this translates to good mold-resistance on the wall.
3. Its moisture-absorption and desorption abilities (hopefully making it a great internal humidity buffer).
4. Its locality, accessibility and affordability (it can be manufactured at backyard scales from waste-stream woods that can often be freely or very cheaply obtained).
5. It’s non-toxicity (assuming you manufacture it from clean, untreated wood) and sustainability (it locks up carbon into the stable plaster like all bio-aggregates and can go right into the garden at the end of its life).
To give this a try I will be manufacturing my own Biochar, crushing it into a medium-grain aggregate and mixing it into a mostly non-hydraulic lime binder. I will then be thickly applying it (4- 6 cm total thickness in 2 or 3 coats) to the interior surface of cold, uninsulated, single-skin modern cement bricks that make up the walls of a small outbuilding which we are converting into a home office.
I’ll keep this thread updated with my progress. I’m very interested to see where this goes and I hope others will be as well.
I’ve found one example of a similar thing being done by the Ithaka Institute, only they used clay as the binder instead of lime.
Ithaka Institute - Building material
www.ithaka-institut.org
The attributes of Biochar that indicate that it may have great value as an insulating material are:
1. Its low density / high porosity (google images of Biochar under microscope) which should trap lots of air and make a good insulation.
2. Its stability / longevity (Biochar is said to last for THOUSANDS of years even when buried in moist, life-rich soils). I’m hoping this translates to good mold-resistance on the wall.
3. Its moisture-absorption and desorption abilities (hopefully making it a great internal humidity buffer).
4. Its locality, accessibility and affordability (it can be manufactured at backyard scales from waste-stream woods that can often be freely or very cheaply obtained).
5. It’s non-toxicity (assuming you manufacture it from clean, untreated wood) and sustainability (it locks up carbon into the stable plaster like all bio-aggregates and can go right into the garden at the end of its life).
To give this a try I will be manufacturing my own Biochar, crushing it into a medium-grain aggregate and mixing it into a mostly non-hydraulic lime binder. I will then be thickly applying it (4- 6 cm total thickness in 2 or 3 coats) to the interior surface of cold, uninsulated, single-skin modern cement bricks that make up the walls of a small outbuilding which we are converting into a home office.
I’ll keep this thread updated with my progress. I’m very interested to see where this goes and I hope others will be as well.