Sustainable construction

Portsmouth City Council is mandated by central government to build around 800 new homes every year, till 2036, yet it also intends to reach net-zero carbon emissions before then. The only way the carbon neutrality target can be met is by building eco-homes sustainably.

The national goal is for the Dutch economy to be fully circular by 2050, using 50% fewer primary raw materials by 2030. In response, Amsterdam municipal authorities have defined criteria for sustainable construction to help, yet also challenge, the private sector. This applies to all demolition, renovation, transformation and new construction of buildings, as well as civic and hydraulic engineering within the city boundaries. The chain of subcontractors also falls within scope, even if they are located outside Amsterdam. These criteria cover materials, energy, water, ecosystems and resilience. Results so far include:

• These criteria included when leasing public land for three housing developments (up to 1,500 homes) and a business park
• Circular construction training was provided for large contractors, and a city-wide network developed to promote the recycling of concrete.
• The municipality will reuse old baked bricks for 100% of public realm works – saving money and materials.
• A reduction of 500,000 tonnes of CO2 per year (around 2.5% of current emissions) in the construction chain alone.

Southsea Coastal Defence scheme is aiming to be a zero waste project so is reusing concrete and stone from the existing sea defences as fill materials for the new structures. Normally these materials would be taken away in lorries to landfill and then new materials brought in, also by road. It is estimated that reusing and processing materials on site will save 24, 600 lorry movements, and nearly 4000 tonnes of CO2. That is a 98% reduction of CO2 compared with landfilling these materials. It will also save the scheme and taxpayer over £2m.

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