This technology was developed in the 1930s, and the building panels made using it have been marketed internationally for 50 years. It has been used in 350,000 houses in the UK.The technology enables internal construction panels and loadbearing elements to be made solely from compressed straw. The fibres are bound by their own resin. The straw is covered by a recycled paper, bonded to the straw by a thermosetting resin such as natural casein. The panels can be finished with plaster, wallpaper, paint etc.
The products have very competitive performance properties, in terms of strength, ability to accommodate any fixing method, fire and fungal resistance (for some products boron and similar chemicals are mixed in, but this is not absolutely necessary; some problems in the 1970s with mould have long since been remedied). The product is made to BS4046. Boards are typically sold in panels 2400×1200 and any thickness from 25mm to 75mm.
The sustainable engineering features lie in:
- Use of surplus and recycled materials
- Use of an annually renewable material; carbon-positive by locking up carbon
- Use of bioresin
- Recyclability
- Very competitive thermal conductivity of 0.101 W m2 C, an excellent base for associated insulating products. Lower u-values than 2006 Part L easily achievable
- High performance and materials points under Sustainable Code for Homes.
Strawboard is a viable replacement in construction for products such as gypsum board, timber and timber products, clay bricks, and lightweight concrete bricks. Because it is loadbearing it is possible to build an entire structure out of strawboard, and these do exist in the UK. The installed cost ranges from cost-neutral compared to standard build systems to less than 10% extra.
The East of England company behind the technology licenses plants around the world.
