Developing Low Carbon Build Specifications (Sunderland City Council)

Developing a suite of zero carbon specifications for refurbishing the council’s current properties and building new ones.

At a glance

Housing Advisers Programme case study

2020/21 cohort 

What went in

Priority area addressed:  Driving forward carbon reduction, energy efficiency and the use of zero carbon technologies.  

Budget: £20,000 

Time taken to achieve outcomes: Seven months 

Resource required: External Architect and SAP consultant 

What came out

Deliverables: 11 specifications produced to address the priority area and meet 2021 changes to Parts L and F of the Building Regulations, and the principles of PAS 2035.


Executive Summary

The aim of the project was to develop construction specifications for future refurbishment projects and new build developments, to help drive down carbon emissions throughout the city. A fabric first approach was required with alternative low / zero carbon heating technologies explored where possible. 

A project brief was developed, and a mini competition tender process was completed through Sunderland City Council’s professional services framework. The project contract was awarded to BDN Architects to produce the specifications, along with Dewpoint Energy Services Ltd who supported BDN with the SAP calculations. 

Two existing Sunderland City Council housing stock dwellings were chosen to survey. These two properties are of typical construction type and style to Sunderland City Council’s housing stock, and were used as baseline specifications, to determine specification requirements to achieve an EPC C rating and zero carbon. 

New build specifications were also produced to determine specification requirements to achieve an EPC B rating and zero carbon. Different types of construction were explored for future development, including traditional cavity construction, timber frame and insulated concrete formwork (ICF). 

A total of 11 specifications were produced as follows: - 

New Build Specifications:  

Timber Frame – EPC B rating  

Timber Frame – Zero Carbon 

Traditional Cavity Wall Construction – EPC B rating 

Traditional Cavity Wall Construction – Zero Carbon    

Insulated Concrete Formwork (ICF) – Zero Carbon   

Existing Specifications: 

Dormer Bungalow (1.5 storey) – EPC C rating 

Dormer Bungalow (1.5 Storey) – Zero Carbon 

Semi Detached – Cavity Wall Construction – EPC C rating 

Semi Detached – Cavity Wall Construction – Zero Carbon 

Semi Detached – Solid Wall Construction – EPC C rating 

Semi Detached – Solid Wall Construction – Zero Carbon 

The specifications are for guidance only due to all properties being different in construction style, size and type, occupancy level, state of repair and current energy efficiency. All the specifications have been produced to meet the requirements of 2021 Parts L & F of the Building Regulations, and the principles of PAS 2035 have been considered. 

What's Next?

We will use the specifications as guidance for future new build developments and retrofit projects. We plan to expand on the specifications and provide estimate costs for each specification scenario.   

The specifications were revisited in March / April 2022 when the new SAP software was updated, to ensure they still met the Building Regulation requirements through SAP.