Changes to Building Regulations - From June 2022
Part L for Extensions Pocket Guide
In June 2022, significant revisions to approved documents Part L and F, as well as the introduction of a new document called Part O, were released in England. These changes are likely to impact the projects of tradespeople and self-builders, and it is expected that there will be additional updates in the future.
This guide will provide an overview of the changes that have occurred, the reasoning behind them, and helpful information to help clarify any confusion and guide you in the right direction.
Reasons Behind The Change
These updates have been made with sustainability in mind, with the goal of protecting the planet and creating better homes. The UK government, specifically the Department for Levelling Up, Housing and Communities, has implemented these changes in order to help the country reach its Net Zero target by 2050.
These changes, known as the stepping stone towards the introduction of the Future Homes Standard in 2025, mainly focus on improving the heating and power systems of homes in England, with similar updates also taking effect in Scotland and Wales.
Heating and powering homes in the UK accounts for approximately 40% of the country's total energy usage, so any improvements in this area can significantly reduce our carbon footprint. The Future Homes Standard, which will significantly alter the way residential properties are built in England, aims to ensure that all new homes will have 75% to 80% fewer carbon emissions than those built in 2019.
Some existing homes and retrofit projects will also be subject to higher standards. These regulations updates are preparing us for even bigger changes in 2025, which will require a 30% reduction in carbon emissions in new dwellings and a 27% reduction in existing ones. It is important to understand these updates and stay informed about them.
The Changes
It is important to be aware that these updates apply to new builds, existing homes, extensions, and non-domestic projects. All projects submitted for building control will now need to meet these new standards.
Part L
One of the most significant changes is the consolidation of the document, which now covers newly built homes, extensions, renovations, and change of use buildings in one document. The energy efficiency of new homes will be assessed using a new Standard Assessment Procedure (SAP) calculation called SAP10, which will be conducted twice, once at the design stage and once upon completion of construction. Previously, this assessment was done using SAP 2012, but SAP10 has higher requirements for CO₂ reduction, aiming for a 31% improvement compared to previous standards. The SAP10 assessment will measure two figures: the Dwelling Emission Rate (DER) and the Target Emission Rate (TER). These figures will determine whether a new dwelling passes or fails this part of the assessment. The DER and TER can be improved by making changes to the building fabric in accordance with new minimum fabric efficiency standards, such as using better insulation and more efficient windows and doors. The new regulations also prioritize the use of renewable and low-carbon energy sources, such as heat pumps and solar panels.
New Build - Insulation Changes
One of the main changes to new build properties is that cavity wall, below ground level, and between ceiling rafters and floor insulation must now have a minimum thickness of 150mm. Previously, the minimum requirement was 100mm. Alternatively, high-performance insulation can be used to reduce the cavity size.
For sloping ceilings, 150mm insulation must be used between rafters and 50mm underneath. For horizontal ceilings, 400mm mineral/glass wool products must still be used.
New Build - Windows
In the new regulations, windows in new build properties must have a minimum U-Value of 1.2w/m2K. For renovation and extension projects, the minimum U-Value is 1.4 w/m2K (this was previously 1.6 w/m2K).
Extensions & Renovations - Insulation Changes
When completing a renovation or extension project, ask yourself the following questions:
- Are you replacing more than half of a surface such as a wall, floor, or roof?
- Are you adding a new layer by dry lining an internal surface?
- Are you replacing an existing layer by stripping down an element to expose structural components?
- Are you replacing the waterproof membrane on a flat roof?
- Are you adding new cavity wall insulation?
If you answered yes to any of the above questions, you will need to ensure that the following requirements are met:
- The floor insulation has a minimum thickness of 100mm (previously 75mm).
- The horizontal ceiling insulation has a minimum thickness of 300mm (previously 270mm).
- The insulation in a sloping ceiling is 150mm between rafters and 30mm underneath.
Part L Compliant Products:
Renewable Energy
Solar panels have been around for a while, but with the Part L regulations now requiring more renewable forms of power, they are becoming more popular.
Installing solar PV is a good way to meet SAP10 measures and comply with Part L and the Future Homes Standard for both new build and existing properties. Solar panels are popular with homeowners and housebuilders, and their demand is expected to increase leading up to 2025. If a new build project has a traditional gas heating system or an electric boiler, solar panels must be installed, or the home must use a ground or air source heating system to meet SAP10 requirements.
The latest solar panels are easy to install and maintain, and are highly efficient. Solar PV systems can increase property value by thousands of pounds and reduce running costs by over £300 per year.
At Tippers, we are here to help with renewable technologies. Our branches are here to help and advice on the right technologies for your home. We work with Grant UK to offer a free specification service for their Aerona3 Air Source Heat Pump Range. We also offer a Free Underfloor Heating design and specification service. Click here to find out more.
Wastewater Heat Recovery
One of the significant changes in the updated regulations is the recommendation that wastewater heat recovery systems be used in any new build projects.
The inclusion of wastewater heat recovery systems in new build projects is a significant advancement in reducing heating costs for customers. These systems, which can recover around 60% of the heat lost down the drain for use in heating new water, are relatively easy to install but can make a big impact. It is important to remember that showers, including those over baths, should always be connected to the wastewater heat recovery system.
Lighting
If you are an electrician, you should be aware of the changes to lighting requirements. As of June 2022, you will need to submit your full lighting designs to Building Control before starting the work. You will also need to consider the efficiency of the lights by measuring the amount of light produced per Watt of energy. For fixed lighting, you must ensure that there are 185 lumens per m² of total floor area and that each lamp has a minimum efficiency of 80 lumens per watt.
Click Here to see our range of lighting.
Part O: Preventing Overheating
As homes become more efficient in the coming years, it will be important to keep them warm and comfortable, but not too hot. Part O of the regulations has been added to help prevent overheating in buildings.
Part O requires that the risk of overheating in each room of a home be evaluated and that adequate cooling measures be included to prevent occupants from getting too hot. Rooms with large glass windows, such as conservatories, are particularly at risk.
Part F – Ventilation
Ensuring proper ventilation in a property is essential for sustainable building, energy efficiency, and occupant well-being. Adequate extract ventilation is required in wet rooms, and whole dwelling ventilation is needed to supply fresh air either mechanically or through background ventilators. Many fans may meet Part F requirements, but they must be tested in situ with ducting attached to be considered valid. A commissioning certificate must be provided to Building Control. If working on an older house that may not have sufficient ventilation fans, the existing ventilation system may need to be evaluated and potentially replaced to meet the requirements.
There is a recommendation that all replacement windows be fitted with trickle vents unless there is an alternative form of ventilation, such as air bricks or whole house Mechanical Ventilation with Heat Recovery (MVHR). MVHR systems provide better energy efficiency and less heat loss compared to traditional home ventilation systems. These systems are compact and can be retrofitted into conventional masonry, even in older buildings, or incorporated into the masonry of new build properties. Including an MVHR unit in new builds can improve indoor air quality and reduce the risk of condensation damp forming in areas with poor circulation.
Documenting Your Work
You are now required to take photos of your work at specific points in the project. These will need to be uploaded to Building Control for approval.
Jargon/Questions Explained:
- What’s a U Value? - The U-Value of a structure is a measure of the rate of heat transfer through it, expressed in units of W/m²K. A lower U-Value indicates better insulation.
- What do I do if I’ve already started a project and not complied to the new regulations? - There is a short grace period for Part L 2013 notices submitted by June 2022. Under the transitional arrangements, customers have until June 15, 2023 to begin work on a dwelling-by-dwelling basis. Projects where work has not started by June 2023 must comply with the new Part L regulations.
- How can I ensure I’m specifying and using the correct compliant materials for my projects? - Our helpful branch teams are on hand to offer help and advice on suitable materials for your projects. We are also able to offer SAP calculations, Air Source Heat Pump system design and more.
