The 5 Key Stages of a PAS 2035 Retrofit Project

Successful retrofit is about more than installing insulation, replacing windows or upgrading heating systems. For housing providers, each home needs to be considered as a whole, with the condition of the building, resident needs, risks and interaction between measures all taken into account.

PAS 2035:2023 provides a framework for managing domestic retrofit from initial assessment through to design, installation and evaluation.

Here are five key stages of the process.

1. Initial Engagement and Planning

Every retrofit project starts with understanding the property, its occupants and the objectives of the project.

This can include reviewing:

• Property age, construction and condition
• Existing insulation and heating
• Ventilation
• Damp, mould and moisture issues
• Energy performance
• Occupancy and resident requirements
• Planned maintenance and asset-management priorities

The aim is to establish a clear understanding of the property before retrofit measures are considered.

2. Retrofit Assessment and Risk Management

A detailed assessment helps determine which measures are appropriate and identifies potential risks before work begins.

This may include assessing the building fabric, heating, ventilation, moisture, condensation, existing defects and the interaction between proposed measures.

For example, improving airtightness without considering ventilation could create unintended moisture or indoor-air-quality issues.

For housing providers, this assessment is particularly important when managing different property types across a larger housing stock.

3. Design and Coordination

The assessment findings are used to develop the retrofit strategy and, where applicable, a Medium-Term Improvement Plan (MTIP).

Potential measures could include:

• Insulation
• Airtightness improvements
• Window and door upgrades
• Heating and hot-water improvements
• Low-carbon heating
• Ventilation
• Renewable technologies

The key is that measures are considered together rather than as individual interventions.

The Retrofit Coordinator plays a central role in overseeing the process and coordinating the relevant parties throughout the project.

4. Installation, Quality Assurance and Handover

Good design needs to be matched by good installation.

Works should be delivered in accordance with the relevant design, standards and requirements, with appropriate quality assurance and management of any issues identified during installation.

Unexpected defects or changes to the property should be properly assessed rather than simply dealt with on site without considering their wider impact.

Handover should also provide the housing provider and resident with appropriate information about the completed works, particularly where new heating, ventilation or controls have been installed.

5. Evaluation and Monitoring

Retrofit doesn’t necessarily end when the installation is complete.

Evaluation and monitoring can help determine whether the intended improvements have been delivered and identify any issues requiring further attention.

For housing providers, the information gathered can also help inform future retrofit projects, maintenance programmes and wider decarbonisation strategies.

Good record keeping throughout the project provides an important evidence trail for future maintenance, review and further improvements.

Why PAS 2035 Matters

PAS 2035 provides a structured approach to domestic retrofit based on a simple principle:

A home is a system, and changes to one part can affect another.

For housing providers, following a coordinated approach can help identify risks, improve quality, support resident outcomes and provide better oversight of retrofit programmes.

PAS 2035 should therefore be more than a compliance exercise. It can provide a framework for making informed decisions about how existing homes can be improved safely and effectively.

Retrofit Compliance Support for Housing Providers

At Assura Consultancy, we provide retrofit compliance consultancy and support to housing providers, helping organisations navigate PAS 2035 requirements and manage the complexities of domestic retrofit.

Our services include PAS 2035 compliance, Retrofit Coordination, project reviews, quality assurance and retrofit programme support.

If you are planning or delivering a retrofit programme, get in touch with our team to discuss how we can support your organisation.