Transforming two derelict houses into six energy efficient, future proofed flats for use as emergency accommodation
The Cityzen team was appointed post planning for technical design through to tender, and overseeing the works through the construction stage. There were several challenges presented by this project, not least an existing building being held to new build planning conditions.
Existing Building Challenges
One of the first challenges with this project was that no measured survey had been undertaken prior to the planning permission being obtained, due to the presence of asbestos. As soon as COVID-19 restrictions allowed, asbestos was removed and a 3D survey was obtained.
The survey established that achieving the council goals for occupancy was not possible within the existing planning approval. At the same time it was noted that the planning design showed most of the internal structure being removed. The council had a commitment to reusing as much original structure as possible, while also needing to meet National Housing Standards for funding requirements.
Thus a redesign was undertaken to achieve the council goals, and due to project timescales while a revised planning application was under consideration, we continued the technical design of the revised scheme at risk. We were able to issue the architectural construction package for tender just 12 weeks after the survey was received.
In the meantime Adur and Worthing planning were pragmatic and approved the revised scheme as an amendment to the existing planning permission.
The existing planning approval included a block of new build flats, and thus the refurbishment was subject to the same planning conditions as the new build. A stretching requirement in terms of performance (acoustic and overheating) but one the council did not wish to shy away from.
Achieving Design Goals
Due to the site being on a busy coast road with the railway line behind it, the acoustic specifications that were part of the approved planning conditions, were not able to be easily met within a social housing refurbishment budget, or through the use of refurbishment products on the market. The project had to therefore show that all practicable mitigations had been undertaken and demonstrate the improvements. Cityzen worked with specialist consultants across the project to provide additional expertise in order to achieve the best possible thermal and acoustic results.
The council policy goal of no gas, budget, and ongoing maintenance requirements, led to an employer’s requirement for electric storage heating. As this was to be temporary accommodation a key design team goal was therefore to ensure the future occupants of the properties had relatively lower running costs, and this was achieved through developing a design specification with low heating demand.
The existing overheating risk arising from existing south-facing large format bay windows was increased by the acoustic planning condition. Environmental night time noise required windows to remain closed. The structure of the buildings and the budget didn’t allow for the favourable solution of a ducted ventilation system.
To ensure the specification was optimised the design was interrogated as it was developed by iterative SAP energy assessments by SEA Compliance, and iterative overheating TM59 assessments by XDA Consulting enabling the design team to develop a suitable way forward that addressed the need for high thermal performance and reduction of overheating risk.
Anderson Acoustics then interrogated the preferred design specification and were able to confirm that it should address the acoustic needs they had identified, subject to on-construction re-assessment.
The final specification of solar control glazing, blinds, system 3 ventilation and purge fans in heat sensitive rooms removed the overheating risk in 25% of the bedrooms and, in the most-at-risk bedrooms, the total overheating hours were reduced by 74%.
Throughout the project, the design and constructive teams worked closely together to ensure the project was delivered in the most cost-effective way possible. With the main contractor, Cheesmur, being proactive in not only addressing problems on site, but also drawing on past experience from previous council projects to suggest new ways of achieving the desired results.
The cost plan by MGAC (RLF at the time) was firmed up prior to tender thanks to a period of strip out, and further existing condition investigation by ourselves and QED Structures.
Above and Beyond Results
Acoustic and air permeability assessments were desired to demonstrate the performance of the detailing and build. We are very pleased to say that the acoustic assessment demonstrated that the night-time noise risk had been completely removed. A fantastic result given the location of the properties. The air permeability assessments showed that air permeability averaged 7.6m3hr/m2 an excellent result given 15 would have been acceptable for an existing building, and given that air tightness detailing was not part of the original brief..
After the build, we produced ‘how to’ videos for use within the council welcome package to assist occupants with learning how to use the heating, hot water and ventilation fans. As well as covering health and safety aspects such as hob safety and how to ensure the fire and smoke alarms are working.
The council successfully applied for funding through Homes England’s Affordable Homes Programme (AHP) and Rough Sleepers Accommodation Programme (RSAP) and residents from the emergency housing list are now living in the properties. A fantastic result from all of the hard work put in by everyone involved.