The need for sustainable building methods has never been more important
We’ve heard about the shortage of gypsum plaster due to Covid19 but have you heard about the global shortage of sand?
Sand is becoming an increasingly scarce resource and as the second most used natural resource behind water, it has a significant impact on the world economy. Increased building has meant that world demand is now outpacing natures ability to make more. To put this into context, between 2011 and 2013, China used more concrete than the United States used in the entire 20th century.
But it is not only the shortage of sand that needs addressing. The production of cement, in particular the glue that combines the materials, Portland cement, contributes 8% of the worlds CO2 emissions. This figure is predicted to grow to 25% by 2050. Without a significant change in the management of sand and a change in attitude to building we may well run out far sooner than we think.
The good news is that this shortage doesn’t mean we have to stop building or restoring. We just need to look at our methods to find alternatives.
The heritage building sector has always been a champion for looking to the past for proven building methods and it could be the heritage sector that comes to the rescue in this global peak sand shortage.
Scientists across the world have been researching alternative materials to use as a partial or full replacement for natural sand in cement and lime plasters. Materials such as fly-ash, quarry dust or limestone and siliceous stone powder, construction waste, sheet glass powered, filtered sand, and copper slag; many of which are already used in the heritage sector. There are many potential alternatives but just as many obstacles with their use. It is often assumed that well graded, washed sand is the only option however historically builders would have used local aggregates ‘as it came’. This would mean that additives may have been added to make a mix workable. The same will be the case with any new alternative materials. It is unlikely that there can be straight swap and therefore builders will need to have a deep understanding of how materials can change the properties of a final mix.
A further obstacle is that despite there being some significant advantages to these alternatives, there isn’t the volume of them locally to substitute sand completely.
If you have been to one of our talks or courses, you will have heard us say over and over that ‘one sizes doesn’t fit all’. This is certainly the case with sand alternatives meaning more research needs to be carried out. In the short term, as building contractors and professionals, we should always be mindful of building in a sustainable way.
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