The embodied carbon connected to the materials used for construction can be a significant impact when looking at the whole life cycle of a building, as described in the RICS Professional Statement “Whole life carbon assessment for the built environment”.
We can take a Stage 2 cost plan, or quantities from BIM information, and quantify the material impacts of the current specification. This would allow for visualisation of the impacts of each of the building elements, and can be used to identify opportunities for reducing the total, compared to the LETI and RIBA 2030 challenge metrics for Net Zero Carbon.
Case Study – Rammed Earth Classrooms
Working for East Sussex County Council, ECE were appointed as Architect to deliver 3 Creative Learning Centres, using rammed earth, green roofs and Air Source Heat pumps for heating.
The CLCs use load bearing rammed earth walls reclaimed from local sites, exposed internally, as the primary structure. Dry mixed from chalk and aggregate and then poured into shuttering, the material is pneumatically rammed to form a strong durable wall. As there is no cement in the mix the amount of CO2 and energy used in the construction in minimal.
The rammed earth is insulated by sheep’s wool, a natural fibre from a fully renewable resource, placed between timber studs and clad in locally sourced cedar. The rammed earth structure supports the green roof which is built up from a layer of cork insulation, a rubber based membrane and topped with a sedum blanket which reduces C02 and other pollutants from atmosphere and slows water runoff, helping mitigate localised flash flooding. Rainwater goods will be zinc or rain-chain downpipes, able to be reused or recycled.
Insulation for the floor is provided by warm-cell recycled paper insulation, a cellulose fibre extracted from 100% recycled newspaper, thus reducing waste to landfill. Where appropriate the concrete for the foundations will use recycled aggregate.