Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?
Compressed hemp block (dry-molded, distinct from cast hempcrete)
Passive
One of 11 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
Blocks made of chopped hemp stalk and lime, pressed into shape and dried in the air, then laid like bricks between the posts of a timber frame. They insulate well, and take about a quarter of the energy to make that fired bricks or concrete blocks do.
Similar range to cast hempcrete, 100+ years if kept dry, same binder chemistry, different forming method
Embodied carbon
Low
Space / material use
Medium
Output timing
None
Skill to repair
Basic
Regulation (FR example)
New construction falls under RE2020, which sets thermal and carbon performance thresholds for the building as a whole rather than approving individual materials.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Compressed hemp block (dry-molded, distinct from cast hempcrete) (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want hemp-lime walls laid like bricks, with no wait for a cast mix to dry.
Wood wool insulation board Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want rigid boards that also cut noise.
Straw or hay-based insulation blocks Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Intermediate · Upkeep: Light · Change to daily life: None · Works without the grid: Yes Choose it if straw grows near you and you want insulation that costs very little money or energy.
Sheep's wool insulation Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want insulation that is pleasant to handle and keeps working through damp.
Hemp-lime (hempcrete) wall infill Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want a seamless, breathable wall cast or sprayed around the frame.
Cellulose (blown-in) insulation Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want the cheapest way to fill existing walls, floors or a loft without opening them up.
Cork insulation Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want insulation that does not rot and that pests leave alone, even in damp spots.
Light straw-clay infill (torchis leger) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Intermediate · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want a warm, healthy wall made from clay and straw found nearby.
Vacuum insulated panel (VIP) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Specialist · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you need strong insulation where there is almost no room for it.
Mycelium (fungal) insulation panel Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want to grow your own insulation at home.
Lime-hemp (chaux-chanvre) insulating render Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Light · Change to daily life: None · Works without the grid: Yes Choose it if you have old masonry walls and want them warmer and drier while they keep breathing.
We don’t list sizing or quantities, as the yield of each technique depends on the quality of its build. The catalogue compares options but doesn’t dimension them. Regulatory notes are indicative, with a French example, and need to be confirmed locally.