Trustmark Approved Retrofit of a 40 Flat Hostel

• The properties averaged an EPC rating of D
• Heating was provided by aged night storage heaters which were inefficient, difficult to control with no incentive for user behaviour change with regards to operation.
• Hot water was provided by hot water calorifiers heaters via electric immersion heaters augmented by a gas fired CHP system which was at the end of its life cycle.
• The building structure was subject to roof leaks, structural defects, and poor thermal performance.
• Hot and cold water delivery to water outlets was poor due to low system static pressure and aged galvanised distribution pipework.

In response, Waltham Forest Council seized the opportunity to improve Southfield Court’s fabric further and install more efficient and sustainable energy sources. This aligned with their work towards reducing emissions and enabled them to take advantage of funding from the first wave of the Social Housing Decarbonation Fund (SHDF).

Funding
This project was funded by Social Housing Decarbonisation Fund £500K (SHDF Wave 1) and Carbon Offset Fund £460K (COF) and the Council’s Capital funds.

The Solution

ASHP
Air source heat pumps are in place and Southfield Court is no longer reliant on gas. Its burden on the local power grid has also decreased thanks to its more efficient use of electricity and the power generated by the solar panels. Aston Group will be keeping a close eye on the system’s efficiency thanks to the remote monitoring system.

The ASHP’s were all located at roof level following an Acoustic Assessment and Planning Approval with a louvred compound installed to reduce the breakout noise to surrounding residential buildings.

With these models, 4kWh of heat is produced from just 1kWh of electricity. Thanks to the plan to introduce solar panelling to the property, the heat pumps would also be powered predominantly by renewable energy, making them even more efficient and carbon-saving. This would also allow Southfield Court to remove itself from the gas grid.

In this case, both air source heat pumps operate on a ‘wet’ system.

All of the pumps were installed on the roof to keep noise disruption to a minimum and to save on space. These air source heat pumps required a large plant, which was more easily accommodated on the roof than elsewhere on the property’s grounds. To reduce noise further, a surround was erected. This surround also hides the units from view and assists in wind deflection – if wind blows against the heat pump’s fans, they will not work effectively.

Solar PV
To equip Southfield Court with solar panels, we selected products from Trina Solar, a well-known and reputable brand. Their panels are included on the BNEF (BloombergNEF) Tier 1 list thanks to their efficiency and reliability, making them a perfect choice for this project.

We also took the finished aesthetic of the solar panels into consideration so that they would be in keeping with the new outer rendering of the finished building. We subsequently chose all-black panels, which would be laid out in blocks. This not only provides a more pleasing final appearance but ensures space on the roof is maximised.

In total, 62 modules were installed and they are already exceeding expectations: our estimates stated that the panels would produce 19,485 kW/h, but early data has revealed that this figure is actually in excess of 20,000 kW/h.

Resident Considerations
The project to improve Southfield Court required extensive work to both the exterior and interior of the property. Access to its 40 flats was therefore absolutely essential. However, the flats would not be empty. As a key part of Waltham Forest Council’s accommodation provision for vulnerable people, the flats remained occupied throughout the renovations.

Protecting residents from as much disruption as possible, and keeping them fully informed of the work that would be happening, was a priority for the team at Aston Group. But given the particular circumstances of Southfield Court’s residents, it was even more important to keep them as comfortable as possible throughout the process.

Communication with residents was key to the project success, this was achieved by our site dedicated RLO resource. Retrofit provides major energy efficiency boost for tenants — Aston Group

Added value was also provided by designing an independent steel beam structure to the roof area to enable the roof mounted ASHP’s and Solar PV panels to be installed negating the need to disturb residents with intrusive roof works and potential temporary rehousing. Due to the borough housing pressures, the works needed to be undertaken whilst all the residents remained in occupation.

Ventilation
At Southfield Court, there wasn’t a discernible issue with moisture or condensation within the 40 flats. However, some of the ventilation was found to be installed incorrectly. One resident, also reported that she had a “humid smell” in her bathroom. In addition, we recognised that the addition of external wall insulation would effectively ‘seal’ the fabric of the building. Without effective ventilation, there could be damp issues in future.

To prevent this, we installed a system of mechanical ventilation featuring Greenwood CV3 extractor fans. These were chosen because they are easy to set up and control, and they boast airflow-sensing technology. This allows each unit to react to moisture and alter its performance accordingly.

Trustmark Accredited
We worked closely with ECO Surv’s Retrofit Services, our retrofit Coordinator who examined our work throughout and certified that the PAS 2035 processes had been followed and succeeded in achieving the TrustMark accreditation.

Throughout all stages of the project the Department for Energy Security and Net Zero (DESNZ) were consulted and informed of the progress and the measures installed.

The succuss of this consultation is reflected in DESNZ visit to site (DESNZ visited our SHDF Wave 1 project — Aston Group) and our subsequent invitations from DESNZ to support their Retrofit Information Support and Expertise (RISE) featuring the project in a webinar to various Local Authorities and other stakeholders to demonstrate how such projects can succeed. We talked through the works, challenges, and lessons learnt. Aston Group have also been invited to take part in IBM/DESNZ research to support the design of a potential new reporting system to improve grant recipients progress reporting.

We embarked on this transformative journey to not only elevate living standards but to improve energy efficiency through the strategic implementation of retrofit solutions, backed by SHDF Wave 1 funding.

Fire Safety
In addition to passive fire protection, such as re-compartmentalising the building, we also installed new alarm systems and updated escape plans. Our works included:

• Updated records for the Premises Information Box (PIB), which detail vital information for the fire services, such as the position of fire exits and possible sources of heat
• Installation of automatic opening vents (AOV) in stairwells.
• Upgraded fire safety doors
• New fire escape plans and signage
• Upgraded emergency lighting
• Upgraded lightning protection, with new conductors fitted beneath the external wall
• insulation
• Installation of a sprinkler system.
• Painting of walls in fire-resistant paint
• New fire detection system on the roof to monitor the new equipment positioned there

The Results

The transformation has been remarkable. Poorly performing flats now boast EPC ratings of at least a C. Top floor flats were scoring EPC ratings of F before the work. Upon its completion, these have largely been raised to a rating of B due to the new structure and insulation on the roof.

No waste was sent to landfill while 84.67% was recycled and 15.33% used in energy recovery.

As a result of this combined action, our work has been nominated for four awards at the Unlock Net Zero Awards, Collaboration of the Year Award and the Green Homes Upgrade Award and the Inside Housing Development Awards for Best Partnership and Best Healthy Homes Development.

These works were completed with minimum disruption to building users, on time and within budget. On completion we conducted a customer satisfaction survey scoring 97%.