A wide range of plasters exist that are suitable for use with bare walls. They vary in finish from very hard minimum maintenance to softer plasters like earth and gypsum which are pleasing to the touch, easy to repair and have good acoustics. You can have very straight flat walls, softly curving walls, float finished grainy walls or you can texture them by hand to produce beautiful patterns. The beauty of self building is the ability to personalise, possibly incorporating wind and solar power and maybe a composting toilet to make it a truly eco-friendly house. Because of the insulating qualities of straw the bale house is highly energy efficient.
Insulation is rated by R-value, the resistance to heat flow.
The R-value of wood is 1 per inch, brick is 0.2 and fibreglass batts are 3.0. The higher the value the better the insulation. That is two to three times better than the wall systems of most well insulated homes and five to ten times better than some older houses. Most peoples' worries about building and living in a bale house are its' strength, its' fire resistance and bugs. In America where bale houses have been tested since the early seventies they have passed all tests with flying colours and are even showing positive results when tested for seismic resistance.