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THE BRIEF
Retrofit practices lie at the core of sustainable development. It’s estimated around 7 million new homes will be needed across the UK by 2050. Simply building new homes isn’t the answer. We must also look at upgrading our existing housing stock so they are liveable, affordable and efficient. This is where retrofitting comes in.
Cambridge City Council has an ambitious goal of being carbon neutral by 2030. This project looked at existing housing stock on Ross Street and Coldhams Grove as a ‘Net Zero Retrofit Pilot’. All households volunteered for the pilot, a testament to the engagement led by Cambridge City Council.
The pilot focused on semi-detached and terraced housing as well as four flats. The bulk of these were built in the 1930s. The core aim of this project was to improve the occupant’s well-being, through warm homes that are efficient and affordable to heat.
During the planning phase, Cambridge City Council gathered information on the required level of retrofit. This was done on two key factors; the existing level of energy performance and potential disruption to residents. For most housing, a deep retrofit was chosen, allowing residents to stay in the property reducing council costs of rehousing. At all stages, communication was extremely important.
OUR WORK
Spatial Dimensions were instructed on-site by ECD architects as the project’s geospatial surveyors. Survey data would play an essential role in providing ECD with exact information and consequently confirm which retrofit measures were required.
46 of the 50 homes were occupied. Our project management team needed to be in contact with each household before our visit. During these calls, we checked access dates, routes of access and answered any questions to put their minds at ease. Prior to being on-site, our survey teams were briefed on potential issues. As a company, we are aware that entering a home for some residents may be daunting. It’s our responsibility to make these individuals feel comfortable, whilst also being professional and safe.
Measured building surveys were carried out with RTC laser scanners to create exact floorplans and elevations. The floorplans were specified by our client at the level of detail (LOD) 2. The were 10 archetype properties identified for floor plans. Once scanned, these layouts were utilised across the 50 properties. This ensured the project was working to challenging timeframes whilst maintaining the accuracy of data. Elevations for all properties were produced at LOD 3.
Following our initial surveys, 3D models were created in Revit using laser-scanned data at LOD 3. Several companies were working on this project. Utilising digital 3D models ensures collaboration between them is easy. It also meant informed decisions could be made without being physically on-site, saving time towards pressing deadlines.
Topographical information also played a key role in the project planning stages. A 3D topographical survey was conducted at LOD 3. This details the existing footprint of buildings, trees, basic drainage and other information.
The elevation and topographical surveys were external surveys. Whilst contacting the residents we asked private areas were left unlocked whilst carrying out these surveys.
THE OUTCOME
All survey information was delivered on time and within budget. Spatial Dimensions and ECD architects have worked on a number of retrofit projects. Our continued work of this nature is a testament to our great working relationship.
The heat demand on properties was reduced by a huge 600% on the last recordings. As a pilot, findings within this project will inform the next stages of development work within Cambridge. All initial readings are extremely positive.
In a recent article with the Architects Journal, Marion Gray (Senior Architect at ECD Architects), highlighted the importance of national retrofit work. ECD’s measures of building fabric, MEP and renewables have led to these Cambridge homes being net zero. He highlights the importance of public perception, too. In conclusion, as an industry, we must highlight the positives of retrofit at every chance!
