We all know and love that famous children’s tale, of the three little pigs and their respective homes. And we all remember the outcome – the strongest, most stable house, that the wolf just couldn’t blow down. (We may also recall the violent demise of the wolf, but that part isn’t particularly relevant to this blog). What is relevant, is the use of the particular materials that the third little pig cleverly built his house with. Bricks! And although I don’t remember this being detailed in the story, we can assume these were held together with mortar. For those that get confused with the intricacies of building materials (myself), mortar is the ‘glue’ that holds other building materials together, and is composed of cement and sand.
Cement is a big enemy of the environment. Enemy number three in fact: it is the third ranking producer of man-made CO2 in the world, after transport and energy generation. The production of this one construction material accounts for 4% of all Greenhouse Gases, when broken down by industry, so imagine the percentage of emissions for the entire Construction Industry. For some perspective, Air Travel accounts for 3% of all Greenhouse Gases. CO2 is produced at two points during the cement making process, all of this even before the mixing for cement clinker and concrete, the transportation…etc. Not only are emissions at a record-breaking high, the extraction of raw material for cement causes landscape degradation, noise and visual pollution, and the usage of potable water throughout the manufacturing process.
The above image shows the complete process of cement production, with the required inputs and resulting waste outputs, highlighting the extreme wastefulness and inefficiency of the system. [Source] Increasingly, we are seeing other options available to substitute cement in building practices. Such materials include by-products such as ‘fly ash’ or silica fume, from coal-burning power stations, the iron and steel industries and silica manufacturing. Other options include lime and limecrete. By using either an industry by-product, or a cement-free product, wastage is reduced, thereby creating a more circular economy for the construction industry.
Obviously, our needs for construction aren’t going to change, but perhaps the way in which we meet these needs can. Step outside of a developed city, and you can begin to see a variation in construction techniques and materials. Travel to another country, and you may be surprised at the prevalence of buildings that are constructed with environmentally-friendly materials. Bye-bye bricks.
Hello earth, rock, plants…
Whilst travelling, I have come across many different building techniques, and I have been lucky enough to help out with a couple of construction projects. My first taste of bio-construction was with a Belgian family living in the south of Spain. They had reclaimed an old shepherd’s cave dwelling and had turned it into a simply beautiful home. I actually slept in a cave separate from the main cave, which had previously housed the carrier pigeons! I stayed for two weeks, during which I worked on drilling out another cave to create more living space. Using a jackhammer to drill out a mixture of limestone and other rock was a sure-fire way to quickly build up my physical strength, but more interestingly for me, allowed for a real up-close and personal experience with the building material (something that you don’t quite get from bricks!). The main cave maintained a constant toasty 22 degrees, due to the natural absorbency of the rock, meaning less heating and insulation requirements!
Another foray into bio-construction saw me assisting the build of a small house in the village of Purmamarca, which lies above 2300m in northern Argentina. Much of the village is constructed with the traditional methods of adobe – a mixture of earth and other organic materials (think hay, cut expertly with a machete by yours truly!) which can be shaped into bricks, or smoothed on to create finished walls. It is the same in principal as cob, or the ‘daub’ of wattle and daub! After machete-swinging, my biggest task was helping to finish the walls, which meant I had to learn the fine art of applying barro (earth mixed with finely chopped hay). This process was explained to me as “con FUERZA, y con amor” [with FORCE, and then with love], meaning throw a lump of mud as hard as you can at the wall so it sticks, and then you smooth it over with your hand. Needless to say, I ended up wearing a fair bit more mud than the wall! Not only were the building materials natural, but the whole construction site felt more…organic. Several times I found myself wobbling up a ladder, which was balanced on a plank, propped up by a couple of rocks, bucket between my knees, stretching to shove mud into a hole half a metre above my head with one hand, bottle of water to wet the walls in the other, with a plasterers’ trowel clenched between my teeth. Health and Safety inspectors from the UK would have had a field day!
By lessening the usage of heavily processed construction materials, emissions are immediately reduced with the removal of the production cycle. Local materials eliminates the need for transport, and working within resource availability means preventing resource depletion and landscape destruction. By constructing with materials from the locality, buildings are less likely to be so visually intrusive, enabling us to maintain our natural planet without physically altering landscapes.
With the global population ever-growing, and the need for housing more and more apparent, perhaps it is time we started looking to alternative building techniques, in order to create more sustainable housing options. Natural materials offer a solution with minimised impact on the environment, whilst also allowing for architecture and design to sit more readily within the surroundings. So, perhaps straw and stick houses won’t hold up to the wolf’s breath, but slap some mud on top and you’ve got the beginnings of an eco-friendly home.
If you think these techniques are only applicable for non-city dwelling, keep an eye out for our upcoming blog on sustainable cities!
Author: Rachel Calnan