Domestic refurbishment - upgrading the existing building stock

21 January 2020 Kingspan Insulation UK

In 2019, the government set new legislation for net-zero targets, including the requirement that net-zero emissions be met by 2050. Given that approximately 40% of the UK’s energy consumption and carbon emissions come from the way we light, heat and use our buildings, Energy Efficiency Measures (EEM) must be considered - with the focus on the thermal efficiency of the 29 million existing homes in the UK in order to achieve net-zero by 2050. A major factor in achieving this goal is the successful refurbishment of aging buildings in the UK.

It is widely acknowledged that a building’s fabric should be made more thermally efficient and airtight before other EEMs are considered. This is logical considering there are an estimated 7.8 million uninsulated solid walled homes in the UK. This highlights a significant area for improvement. In this blog we will give an overview of building refurbishment, including the various standards in place and explain the ways in which it could be approached.


Guidance on how to meet the energy efficiency requirements of the Building Regulations / Standards, when refurbishing or renovating existing dwellings in the UK, is detailed in the 2013 edition of Approved Document L1B for England, 2014 edition of Approved Document L1B for Wales, and the 2019 edition of Technical Handbook Section 6 for Scotland.

In addition to the requirements outlined in the national regulations, alternative and more stringent guidance for the refurbishment of existing buildings is available, such as EnerPHit, which was born out of the Passivhaus standard. The EnerPHit standard recognises the potential limitations and possible design restrictions of refurbishment work due to the nature of existing buildings, meaning that achieving the energy performance levels stated in the Passivhaus standard would be unrealistic. This standard puts emphasis on achieving minimal energy consumption whilst still providing comfortable conditions for the occupants of the building. Following the EnerPHit standard requires strict attention to detail from design to project completion.


Incentives are in place to encourage refurbishment, for example the Green Deal. The Green Deal scheme is no longer Government funded, however loans are still available through the Green Deal Finance Company for home renovation work that will improve the energy efficiency of a building. Alternative incentives such as the ECO 3 scheme are available, which also support the funding of refurbishment projects.

New standard in retrofit design

Due to the diverse nature of older buildings, adopting a universal approach to all refurbishment projects is unrealistic. A solution to this issue can be found in PAS 2035: 2019 (retrofitting dwellings for improved thermal efficiency) – under the framework of the Each Home Counts review.

PAS 2035: 2019 establishes a suitable method that can be applied to the refurbishment of individual dwellings. Following this standard will determine areas for improvement, identify any design changes and specify any EEMs required. The framework also specifies that the project is monitored and that any lessons learned are fed back to all parties involved in the project. PAS 2035: 2019 extensively advises building occupants on all elements of the refurbishment – even proposing suitable maintenance for the completed project. 

Following the guidelines established in PAS 2035: 2019, a retrofit advisor will discuss refurbishment options with the building occupants in order to identify the most effective improvements that can be made. Priority is given to improving the thermal efficiency of the building as this factor significantly affects the overall energy performance. If the building occupants are satisfied with the suggested work, a full retrofit assessment will be carried out. A retrofit coordinator will use the results gained from the assessment to establish a Medium Term Improvement Plan, which covers the next 25 years. Once the retrofit coordinator is fully satisfied, property improvements can commence - initiating long term benefits for the building occupants and, subsequently, the environment. 

Solutions for retrofit 

Refurbishment plans are specific to each dwelling. Options such as modernising the windows and installing solar energy solutions may be considered, however addressing a building’s envelope, for example by increasing levels of insulation, is often a fundamental step in improving the energy efficiency of a building.

Applying external wall insulation, such as Kingspan Kooltherm K5, is an effective way of improving the thermal performance of a building. External wall insulation offers a number of benefits, including:
•    no reduction of internal floor space;
•    building occupants can be left in-situ; and
•    an opportunity to improve the appearance of the property.

However, applying external insulation to a building is not always the best solution. Internal wall insulation, such as Kingspan Kooltherm K118, can be a practical and efficient solution to improving the thermal performance of a property. The benefits of internal wall insulation include:
•    no impact on the external appearance of the building (which can be especially critical in conservation areas or where local planning constraints exist); and
•    ideal for buildings where external space constraints exist, for example where a property is adjacent to another property or public space.

Refurbishing an existing building may require new solutions to be incorporated into the existing structure; this can result in issues - especially when it comes to the availability of space. Kingspan’s insulation products can help combat this issue, for example the Kingspan Kooltherm 100 range offers the thinnest commonly used insulation products. 

When space is at an absolute premium, products in the Kingspan OPTIM-R range offer our thinnest possible insulation solution, making these products particularly useful when keeping an existing floor to ceiling height is a requirement, or when maintaining a level transition from internal to external areas is important.

What results can be expected as a direct consequence of a refurbishment?

The final aim of refurbishing a building is to significantly improve the overall energy performance, by meeting the requirements of the national standards or any relevant voluntary schemes. The refurbishment of a building should result in decreased energy consumption and heating bills, whilst maintaining comfortable conditions for building occupiers. Other benefits of building refurbishment can include modernised property aesthetics and better overall airtightness. It is clear that making the relevant modifications to existing buildings is vital to the UK achieving net-zero emissions by 2050.

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