Natural Building Materials


This is a list of natural materials that can be used in construction  

(page under development - many more materials to come)

Straw Bales

Use: Structural walls and insulation

Image credit: Strawbuild

Straw bales used for construction are approximately 1m x 0.45m x 0.36m and are usually made from waste straw from cereal crops such as wheat or barley (not hay). They can be used either as loadbearing up to two storeys, or infill within a frame structure. Straw bale buildings are very durable when they have a 'good pair of boots and a good hat', and are not flamable due to being compressed. 


  • Excellent insulation, U-value = 0.13-0.20W/m2K

  • Acoustic performance is very good

  • Breathable (vapour permeable) 

  • Very fire resistant

  • Structural up to two storeys

  • Very durable with evidence of lasting over 100yrs

  • Very good airtightness when designed and built correctly

  • Locks up (sequesters) CO2

  • Compostable

  • Very low embodied energy

Source: Available directly from farms that use a small baling machine

Hemp-Lime or 'Hempcrete'

Use: Insulation

Image credit: Hemp-LimeConstruct

Hemp-lime or 'hempcrete' is made from wet-mixing hemp shiv with a lime binder which provides a natural insulation material with a uniquely effective thermal performance. Hempcrete is usually cast around a structural frame (such as timber), and is either "hand-placed" into temporary form-work or spray applied. It is then left to dry for several weeks before finishes can be applied. It can also be laid in pre-dried blocks. 


  • Highly insulating

  • Good thermal mass

  • Very good air tightness

  • Breathable (vapour permeable)

  • Hygroscopic (naturally regulates humidity)

  • Helps prevent damp & mould

  • Hemp locks up (sequesters) CO2

  • Growing hemp benefits soil, without the need for agrochemicals or pesticides 

  • Lime deters rodents 

Recycled Denim Insulation

Use: Thermal & acoustic insulation

Image credit:

Inno-therm or Métisse are a brand of insulation consisting of 80% recycled denim/cotton, reducing landfill waste. It has a low embodied energy and contains no chemical irritants so is easy and safe to handle without causing allergic reactions. It performs well in conditions of high humidity and helps regulate humidity. It usually comes in rolls or semi-rigid batts which are installed between a standard timber frame, but is also available as loose flock to be blown-in.


  • Excellent insulation, k value = 0.039 W/mK

  • Acoustic performance is very good

  • Breathable (vapour permeable)

  • Helps regulate humidity

  • Fire resistant

  • Resistant to moths and mould fungus

  • Safe to handle and easy to install

  • Recyclable 

  • Low embodied energy


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