One of the reasons I started this blog is due to the dearth of information about riad design and floorplans, in addition to the relative opacity of trim costs such as retractable roofs and carved plaster. This trend continues with my research into achieving thick walls (30 -60 cm) composed of Rammed Earth, Compressed Earth Blocks (CEB), or Insulated Concrete Forms (ICF).
Thick walls are a key design requirement not only for aesthetics, but for energy efficiency, durability, and longevity. I recently came across some information about CEB and Rammed Earth, however the information is one-sided and makes no mention of the disadvantages, true cost, or how to find experienced builders. I managed to find a few notes on disadvantages of CEB and compiled a rough list below:
Compressed Earth Blocks
Advantages
- Longevity
- Fire, Storm, and Insect Resistance
- Thermal Mass
- Potential Local source of supply
- Passive Cooling/Heating
- Breathable/Moisture Equilibrium
Disadvantages
- Cost +10-15% over traditional walls
- Lack of building codes/city certification
- Lack of Insulation
- Lack of discussion on 2 story structures
- Potential of conduit corrosion between layers
- Labor intensive (Rammed Earth requires molds)
The most detailed presentation I have seen on CEB dates from 2014 on Youtube and highlights a lot of the benefits. This presentation does not discuss disadvantages, so I must continue my research and talk to the city. The University of Oklahoma did a research study in 2014 comparing CEB with a home built using traditional walls and I have requested a copy of the results. The next step is reaching out to the local government to see how they view CEB and Rammed Earth and find a regional vendor to discuss the finer points. On a positive note, this seems like a potential pathway to obtaining thick walls and building a resilient house that lasts over a century. Hopefully it is not too good to be true….
-Mike
Project Riad 