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Building Regulations Changes: Explained

Today is the BIG day (if Building Regulations are what get you up in the morning.)

Today is when the new changes to the Approved Document Part L, Conservation of Fuel and Power, Approved Document Part F, Ventilation and the creation of Approved Document Part O - Overheating - come into force.

It is a really positive change which will see buildings built more sustainably, ensuring they harm the planet less and are also cheaper to run for homeowners. The Department for Levelling Up, Housing and Communities have set out the changes, to shift towards a new standard in building, known as the Future Building Standard' which pushes to achieve a mandatory 30% cut in carbon for all new homes and a 27% cut in all other buildings.

The changes are being dubbed a 'stepping stone' towards further reductions in carbon within the built environment, all in the pursuit of the zero-carbon goal.

We have put together a brief summary of the changes and what they will mean for us as designers and specifiers, but also developers and self builders.

But before we dive in - it is worth noting, that if you have a Building Notice or an initial notice, or deposits of full plans have been made or given, these changes will not apply to those developments, providing the building work is commenced by 15th June 2023 (so, basically, you have a year, generally speaking.)

So what are the changes?

Part L

What is Part L: Conservation of Heat and Power?

Part L lists the methods which must be used to ensure buildings are efficient in their energy performance - through the correct specification of materials and their U-Values (U -Value for the newbies, is thermal transmittance, the rate of transfer of heat through a structure... Basically how well a material transmits heat, a low value is good for insulation for instance, as it keeps the heat in and doesn't allow it to transmit through it to the outside, thus being wasted.)

So what are the changes?

Let's start with non-domestic buildings.

The changes to Part L introduce a new principal to measure the efficiency. 'Primary energy' will now be used in combination with CO2 metrics to assess the compliance. The primary energy metric will take into account the method of heating, how efficient the power station is for the electricity as well as the energy used to produce the fuel and deliver it to the property. These will all have an impact on the Primary Energy metric, as for instance, mains gas requires infrastructure and energy use upstream of the property, whereas a ground source heat pump does not, giving them differing primary energy figures.

Additionally, the changes include increases in the minimum efficiency standards for new and replacement thermal elements, windows and doors. For example - walls now need to achieve 0.26W/m2K opposed to the previous 0.35W/m2K. Windows will need to achieve 1.6 opposed to 2.2 as previously - that is the same with roof lights and curtain walling, too.

The efficiency requirements of lighting circuits has been updated, with a minimum efficacy set to 95 luminaire lumens per circuit watt for general lighting, and 85 for display. You can however offset a lower lumens per circuit in one area by having more in another.

New non domestic buildings must have an automated control system if they have a heating system over 180kW.

For domestic dwellings, the fabric efficiency standards are being uplifted, for instance a more strict U Value for walls, from 0.28W/m2K to 0.18W/m2K, there are also uplifts in the U Value requirements for windows, but this is dependent on the type of window.

The new domestic minimum standards of heat transmittance (U-Value)

A big change to the regulations is that extensions will now need to adhere to the SAP10 method of compliance for metrics of the buildings fabric energy efficiency and primary energy, so if you're planning an extension - please bear in mind it must now have SAP calcs which comply, but your appointed Architect can help with this.

On the subject of SAP calcs, thermal bridging details will now be taken into account when compiling SAP calculations, opposed to standard government details.

One final change across all of Part L, is the shift to using a single testing methodology for airtightness - CIBSE's TM23 methodology.

'The changes are bringing us one step closer to decarbonation.' - RIBA

Part F

What is Part F: Ventilation?

How we ventilate our buildings is crucial to how efficient and pleasant they are to be in. For instance, it would be no use having a fully air tight home, with fantastic insulation as you are going to end up in a sealed, hot box slowly filling with nothing but your own breath. Not ideal.

Therefore, we utilise fantastic technology, such as Mechanical Ventilation Heat Recovery systems, which take that precious warm air and swap it with cool fresh air without losing the heat, meaning we get the best of both worlds - the fresh clean area, but also the existing heat, thus not wasting the energy used to heat it.

What are the changes?

Let's kick things off again with non-domestic. The changes are broadly all to do with stopping the ingress of external pollutants, specifying changes around trickle ventilation, Co2 monitoring and air supply rates. As a developer, this is certainly something you can leave your appointed design team to deal with.

The changes for domestic buildings in Part F include an addition of a mandatory checklist to be completed to ensure the developer is aware of the impacts their historic or future work will have on the ventilation.

Recommendations on trickle ventilation are also included in the domestic changes, as well as changing to recommendation regarding mechanical extract ventilation.

Part O : Overheating

What is Part O?

Well, you may never have heard of it before, because it is brand new. It details methods to avoid overheating in domestic dwellings and residential like commercial properties, like student residential, care homes and children's homes.

What does it include?

Part O simply contains routes to compliance based on the building minimising solar gain and removing any excess heat. It includes standards on how buildings are ventilated, taking into account orientation of the state and also dictates the maximum amount of glazing in a single room, meaning rooms like below might no longer be achievable - however, there are ways to work around this, and an Architect will be able to discuss the methods available to retain the glass design you want, without compromising the overheating prevention.

The guidance takes into accounts elements such as security, noise pollution and use-ability of windows, however it does not allow for tree shade or internal blinds, as these can be taken down.

What do you have to do about it?

For domestic residential developers/self builders, this all depends if you have appointed a specialist to work with you on the project, such as a Chartered Architect ...

If you haven't, these changes will all need to be taken into consideration in your building design to ensure it gains building approval. If you don't do this, you run the risk of a Local Authority Building Control Officer inspecting your project and telling you lots of changes are required, which will be time consuming and possibly extremely expensive need to be made to make it compliant. This is why we always advise you speak to an Architect or Technician to ensure it is approved before the spades start flying.

If you have appointed a Chartered Architect, firstly, congratulations on making a fantastic decision. Secondly, you needn't worry too much about these changes as they will all be incorporated into the buildings regulations package of information your Architect will be lovingly preparing for you. If any of the regulations (both generally and those mentioned in this article) create an issue in your project, we are sure that your Architect will be on the phone to discuss. If they don't, maybe look for a new one...

For non-domestic projects, again - this will all be handled by your Architect and/or wider Design Team to ensure you are receiving a fully compliant building in-line with the new changes, leaving you with a more efficient, cost effective building on completion. Any issues which arise which dramatically impact the project, you can discuss these with your design team and react accordingly on their advice.

One change which directly impacts the developer for all projects is that during the project, more evidence is to be required that the building is being constructed to comply with the SAP calculations, with developers also now being required to complete a BREIL Compliance Report (Building Regulations England Part L) along with the SAP assessor to confirm the building's compliance.


To close off this article, (hoorah you might say) it is worth mentioning the reaction across the industry to these changes.

The Royal Institute of British Architects (RIBA) President Simon Alford described the changes as 'bringing us one step closer to decarbonation.' He then called for further tightening of regulations, to ensure the built environment decarbonises at the required rate.

Some commentators feel the changes do not go far enough, but they are certainly a stepping stone towards the Future Building Standard .

Decarbonisation is important and at TFQ we see these changes as a positive move towards buildings being more efficient to run, therefore cheaper on your pocket in the long run, but also, perhaps crucially - less harmful to the environment.

We also see it as further proof that self builders especially should appoint an professional designer early on in the project, to ensure these regulations are met, avoiding the need for costly changes or delays. A swift building regulations approval normally results in a smooth project.

As our built environment continues to grow, we have a responsibility to build with the environment in mind.

Whilst views on climate change may differ, we do have a responsibility to minimise our impact on the planet - and if it means your energy bills are lower each month, with happier, healthier occupants in the process, it is a win-win.

If you would like to discuss the Building Regulations changes in more detail, or discuss your own project's Building Regulations needs, please click the button below and get in touch.



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