As one of the most sustainable building materials available today, it’s no wonder rammed earth is making a comeback.
Oliver Petrovic, managing director of Olnee Constructions that specialises in rammed earth construction, says rammed earth construction in Australia usually refers to stabilised rammed earth (SRE). SRE is essentially a blend of raw materials, mixed with a small percentage of cement, water and waterproofing. The material offers low embodied energy, high thermal mass, strength and durability, zero maintenance, sound insulative qualities, fire resistance, and of course, inherent beauty.
‘If designed well, a home incorporating rammed earth can feel warm inside during cold weather, and cool inside during hot weather, without relying on active heating or cooling systems,’ says architectural designer Zana Wright, whose own home features rammed earth. ‘Another important pro is that earth doesn’t burn, which makes rammed earth a great choice for bushfire-prone areas. After such a horrific bushfire season, it is becoming increasingly obvious that we need to build for a changing climate.’
Due to the fairly specialised and labour intensive process, Zana says rammed earth can be more costly than other wall systems, at approximately $300-$400 per square metre of wall face. ‘However, as it incorporates all the elements of a wall in one, its total cost is not a great deal more than a more complex conventional wall which involves building a structural frame, installing insulation, sarking, exterior cladding boards, interior lining boards, and painting both inside and out,’ Zana says.
Experts hope that with more education, rammed earth will become a more widely used material in Australia. ‘If there were any cons, it would be that it can’t always be built on very small properties or properties with poor access, due to the nature of the construction system,’ says Oliver.