materials. It includes all the extraction, transport and manufacturing processes required before products are ready at the factory for delivery to the customer – such an assessment is known as “cradle to gate” Sequestered carbon (aka biogenic carbon) is carbon locked up in the material for its lifetime of the build, such as carbon in timber, locked into the material this carbon is prevented from entering the atmosphere as a gas and although there are complex accounting reasons to exclude this from an LCA the fact that the carbon is locked away and that replacement trees are planted ends up with sequestered carbon being able to more than offset much of the upfront carbon emissions at completion of the project where natural materials are used, especially when obtained from renewable resources. 4. Build off site or use modular elements The embodied carbon of a building element includes its material footprint and the waste that was generated during its construction. Prefabrication under controlled conditions allows reduction of waste and its associated carbon emissions. Similarly, modular elements permit the efficient use of materials and facilitate the industrialisation/ prefabrication of these elements. 5. Set energy and carbon targets Setting carbon performance requirements or other measures can help you to compare options. And, while the overall goal is finding solutions with lower impacts, these options must perform in a similar fashion to make the comparison valid. 6. Buy local materials Transportation of materials from the manufacturing facility to the building site adds to the account of your building. By buying from local sources, you are reducing the emissions produced during transportation and support the local economy. 7. Design for long life The building envelope is critical for the energy performance of the building. The retrofit of building elements is one of the major strategies in reducing operational energy consumption. Yet, the walls and roof are under constant wear from natural elements that can lead to frequent repairs and maintenance. By using durable materials, you not only reduce the cost and frequency of refurbishment but also reduce the use of material replacement and its associated carbon footprint.
9. Watch out for the effects of paints and finishes Finishes have many purposes, as they can help with the acoustics and thermal conditions inside living spaces.
10. Build with flexibility in mind Space planning can benefit from centralised mechanical, electrical, and plumbing services that can easily be branched out to serve the areas based on need. Also, removable partitions make it easier to reconfigure the space for new uses, design elements to be adaptable and multifunctional. 11. Consider the life cycle cost of the materials you use Cheap now can be quite expensive later as you need to replace more frequently, adding to your operational costs. Also, every time you replace a material, you add carbon emissions to your building account. Examine environmental information provided by different suppliers – such as EPD or carbon footprints. Will their products have lower impact in your building? 12. Design building elements for re-use or disassembly When possible, the building should be designed to be easily taken apart by sections or as a whole. This reduces the impact on other elements when
ABOVE A 1930s detached house dep retrofit to passive standards using wood fibre insulation and natural materials for internal wall insulation and a replacement roof.
Efficient recovery of materials makes it easier to preserve the value of the material for future use. Faay flax core partition wall system uses a flax core located using wooden tracks, the wall can be plastered with lime or clay plaster. Flax is a carbon wonder product, strong, durable and during growth sequesters carbon, each HV84 wood fibre faced panel (at 3m2/panel) sequesters 90Kg of CO2. The wall is demountable for relocation or reuse. BELOW
recovering the building component, it also avoids additional wastage. Efficient recovery of materials makes it easier to preserve the value of the material for future use. The refurbishment or retrofitting of buildings is a necessity in our aging building stock and will continue to be so in the future. The refurbishment can be a result of physical upkeep, the need to improve their energy performance, and/or changes in its use. Regardless of the reason, by incorporating new materials/systems into a building, you are increasing its embodied carbon. Only a life cycle perspective allows you to measure these impacts in time in a holistic way. So, by accounting the embodied carbon, and operational carbon if energy use is impacted, it is possible to measure the trade-offs from environmental and financial perspectives. The key takeaway is that to facilitate the process of refurbishment and retrofitting it is crucial to design the building and its systems for easy disassembly. That way materials can be easily recovered and reused, thus, reducing the extraction of raw materials and preserving the value of the existing ones.
Website: www.ecomerchant.co.uk Acknowledgements and references LETI Climate Emergency Retrofit Guide – A Blueprint on how to retrofit our existing domestic buildings. https://circularecology.com/carbonfootprint-calculators-for-construction. html - Tools for calculating carbon. https://www.oneclicklca.com/ one click LCA life cycle assessment software that helps you calculate and reduce the environmental impacts of your building. Inventory of Carbon & Energy database - The ICE database is a useful source of embodied carbon data, use the link to download the most recent version. UCL Refurbishment & Demolition of Housing. Embodied Carbon: Factsheet
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8. Design a building shell that is easy to maintain It is not enough that you use durable materials in your façade, you need to be able to service it, and replace elements when necessary. This can only be done when the system can easily be taken apart. In this way, you guarantee a longer life and fewer future emissions.
They also have an important aesthetic function, that can translate into our overall wellbeing. Yet, they are amongst the elements that have the shortest lifespans in commercial buildings. For example, internal spaces are reconfigured frequently, eliminating partitions and flooring, and changing the ceiling layout. The aggregated impact of replacing these elements several times during the lifecycle of a building can have a significant overall impact. So, finishes should include low-carbon materials, and allow for the easy recovery of those materials for recycling or reuse.
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