Concrete accounts for 8% of CO2 emissions, far higher than aviation at 2.5%. So if we are to help stop climate change we need to stop using concrete. Even the ‘more sustainable’ forms of concrete that replace some of the Portland cement with alternatives such as granulated blast furnace flag and fly ash have their CO2 omissions reduced by less than 50%.
Finding an alternative to concrete for the ground floor construction of buildings can be difficult, especially if the internal floor level is near the external ground level. Otherwise a suspended timber floor is the preferred option.
However for my own 6m x 9m garden shed there is no excuse. Concrete can be avoided. The base of the shed is made of a recycled plastic grid system (which themselves can be recycled or even better reused). These are pinned to the ground using timber stakes. The trays were then filled with gravel. We laid a ply floor over the grid at the end with the workbench.
The roof is held up using timber scissor trusses where our kayak can be stored. The lintel over the door was salvaged from our
previous shed and all the larch cladding came from Abbey Timber – a local sawmill.