Homes within pre-war social housing estates are typically small and do not meet today’s nationally described minimum space standards. Any work to improve the insulation or air circulation would therefore typically result in a smaller flat size.

External insulation is an effective solution but it presents a planning challenge in historically significant estates where brick detailing is valued. The principle of brick slips added to external insulation offers a compromise acceptable to all parties. Some LPAs do not support them due to outdated perceptions, despite recent advancements making them aesthetically pleasing, cost-effective and low carbon.

Restrictive planning policy presented a challenge at the start of the pre-application processes but collaboration with the LPA and its Design Review Panel (DRP) overcame the initial concerns. Whilst the detailed design of the brick slips will need to be agreed, the provision of material samples and fixing details provided much reassurance to the DRP and the LPA.

Adding electric and renewable technologies to improve energy efficiency may require altering internal layouts, such as relocating boilers or boiler rooms. While internal changes do not need planning permission, adjustments such as altering window arrangements or adding external ventilation might do so. When done across a whole block, the cumulative effect of lots of small changes can be quite significant on the building’s external appearance and may require planning permission.

The need for external alterations needs to be carefully articulated to the planners in the context of the overall retrofit plan so they understand why such changes are required and the benefits that local residents will enjoy from better living conditions.

Adding external insulation to buildings can reduce the width of public circulation spaces, potentially breaching building regulations. It can also impact on open and private amenity space provision.

Many pre-war social homes lack private amenity space, and where there are existing balconies, these often do not meet current standards. Adding external insulation further reduces the balcony size.

Larger balconies with supporting pillars can be provided if the existing structure cannot support them, although these can be resisted because of restrictive design policies, especially in historically sensitive areas. Ultimately a well-designed scheme supported by a well evidenced argument can overcome these challenges.

One of the key purposes of retrofitting works is to improve the energy performance of the buildings and ultimately benefit the lives of existing residents. Notably, and in a cost-of-living crisis, anything which could impact on the provision of a consistent and low service charge for residents would face considerable opposition.

This presents policy challenges as developments are expected to follow the energy hierarchy in the Local Plan 2021 which seeks to reduce greenhouse gas emissions and minimise both annual and peak energy demand under the banner of ‘Be Lean, Be Clean; Be Green; and Be Seen’. Policy SI2 of the Local Plan 2021 relates to the delivery of development in accordance with the energy hierarchy; but our view is that the requirements are largely aimed at new development rather than retrofitting schemes which may include, for example, seeking to improve dated communal energy systems (typically gas based). Delivering in accordance with the hierarchy may not be practical or realistic and is likely to result in unacceptable increases in costs for residents. Tackling this challenge requires early engagement and collaboration with the sustainability/energy officer to agree alternative solutions.

The historic nature of pre-war estates can limit the types of external work that may be considered acceptable and bespoke solutions take time and cost more to develop. Carefully balancing energy performance, design, the needs of residents and historical conservation is crucial.

There is often an absence of policy relating to decarbonisation through retrofit. Whilst there is some emerging policy, this is often focussed on the principle of retaining buildings rather than solutions to decarbonising existing buildings. Those that do encourage decarbonising do not provide a mechanism to help LPAs deal with other competing policies or are focused on retrofitting individual homes and do not address the complexities of doing so for large estates.
 
New targeted policy focussed on a presumption in favour of approving decarbonising schemes through retrofit would be beneficial. This would enable LPAs to cut through competing policy requirements. In the absence of this, it is important to chart a pathway through policy requirements based on a deep understanding of what retrofitting entails and why.

Early engagement with LB Islington officers (Planners, Design, Conservation, and Building Regulations Officers) at Old Barnsbury was crucial to success and built the ongoing liaison with local residents. Workshops and a DRP facilitated a collaborative effort to address the in-principle challenges and competing policies associated with decarbonising the estate. Overall, the concept was praised by the DRP and the LPA and is considered by them to be a pioneering solution which can be a blueprint for other estates facing the same issues to follow. Effective engagement from the outset to delivery is usually at the centre of successful estates renewal projects of this nature.

Careful phasing is critical to minimise disruption to residents and allow works to be carried out in a timely fashion in accordance with project budgets. Planning permission need to include embedded flexibility to accommodate change that may arise from testing and monitoring of completed works and that may lead to better ways of doing things. This flexibility should also allow for technological advancements in the fast-moving world of energy performance and retrofitting and changes to regulations and legislative requirements. Such flexibility helps minimise resident disruption, manage costs, and ensure optimum performance of a scheme over time.

Retrofit works, especially those meeting standards like Passivhaus, are expensive. This is exemplified by the LB Islington’s Draft Retrofit Handbook which estimates (pg.65) that for the comprehensive retrofit of an individual early 20th century flat costs approaching £60,000 per home. Note this cost estimate excludes external wall insulation or improvements to balconies.

Unfortunately, RSLs including Newlon will find it challenging to afford to progress such a pioneering concept without government support or cross-subsidy from wider development work.

The previous government supported social housing improvements through the Social Housing Decarbonising Fund (SHDF), with two waves of funding aimed at bringing existing social housing below EPC band C up to that standard. However, many RSLs struggled to match fund the SHDF programme and commit further funds for a complete retrofit solution. The current EPC rating calculations, at Old Barnsbury is already rated at an of ‘C’ and is therefore ineligible for funding. This is why many other larger, older blocks elsewhere have not used SHDF. Further, SHDF funding on a large-scale estate is also challenging where decant is not possible.