Building Safety Act

History of the Building Safety Act and the Building Regulations.

The building regulations have been a part of the UK construction industry to some extent for hundreds of years (At least 800 years since London’s buildings had initial legal oversight and control). Fire and sanitation were the big hitters in the day and the most risk to society. Spread of flame from one crowded city thatched house to another was all too common and soon chimneys and thatching were being controlled. As ‘late’ as 1666 things remained crowded and timber framing was still the most common construction, then later in that year the Great Fire of London ravaged most of the city, destroying thousands of houses, and hundreds of civic buildings and churches. Similarly multiple fires burned in Edinburgh around the same time. This gave birth to the buildings regulations more closely as we know them with careful specification of distances between, materials to be used on buildings and the like. Over time the controls were expanded to wider areas and other cities applied their own controls. By 1774 a detailed Act was in place in London, with similar detailed controls in other cities across the country. A national building act was proposed in 1841, but not until the early 1960’s did a nationalised and coordinated set of regulations fully materialise.

Today’s regulations are divided into parts, such as structure, drainage, fire, sound etc. To accompany these fairly brief paragraphs that form the legal Acts are a set of documents called the ‘Approved Documents’ which correspond to these separate parts, labelled, A, B, C, D…. etc. The Approved Documents list out in more detail, and sometimes illustrate how something can meet the legal requirement.

Approved Docs

They are the accepted norm for compliance, although are not the only way to meet the regulation if other methods can be proven to be acceptable. However on most householder projects they are complied with as there has to be a very good reason to alternative design criteria, usually also requiring specialist input. (Fire engineer, Acoustician, PassiveHaus registered designer etc).

Typically dramatic new regulation or change is driven by disaster or outbreak (Although thermal performance has incrementally increased over the years). For example the Great Fire of London, or the Cholera outbreaks all resulted in significant changes, improvements or greater control of new buildings. Much more recently the devastating fire at the Grenfell Tower has been a key driver in recent change. Following investigation into this disaster, not only have regulations adapted but there has been a shift in responsibility that has come into force as the ‘Building Safety Act 2022’.

What is the relevance and importance of the Building Safety Act to my project?

Buildings and their methods of procurement are considerably more complicated than they ever used to be and the building regulations more in-depth accordingly. Juggling thermal performance, moisture control, acoustic separation, fire safety, structural integrity, air quality, ventilation, ground contaminants, heating systems and flues, drainage, access constraints, stairs and fall risks, solar gain and security is a day-to-day business for an architect or building designer, and the trades on-site constructing.

Accordingly on more complex buildings a whole design team is usually assembled, with different bodies responsible for a number of aspects of the larger project. The control and co-ordination of this team was lost at the Grenfell Tower refurbishment, without clear lines of responsibility or authority and this is one of the main discoveries from the investigation and what has led to the new Building Safety Act.

Like many complex projects and also many cautionary tales of design failures there were several overlapping issues all at once at the Grenfell Tower fire that was made worse by these layers of errors/oversights. These individual issues may not have resulted in disaster by themselves, it was the sum of the parts that resulted in disaster. The Building Safety Act intends to limit the chance of a similar failure occurring by ensuring more clear lines of authority over the design. By having a formalised responsibility pyramid, rather than all design parties being equal, but also blinkered to their own aspect, better co-ordination and compatibility should be achieved with this oversight.

Project Scale

The Building Safety Act, and the Building Regulations apply to all building projects (even fitting out a bathroom falls under the regulations). However under the Building Safety Act, there are two categories of building type. ‘Normal’ and ‘Higher Risk Buildings’ or HRB’s. HRB’s are typically tall buildings, hospitals or large complexes. It’s not a firm definition, but any building that requires thought to how an evacuation would take place, is likely to be a HRB. The remaining building types still fall under the Act but without the extra legislation ‘gateway’ requirements of an HRB.

Tom Spriggs Architect Ltd, does not work on HRB buildings and this post’s target audience is an owner of a dwelling starting their journey to make alterations and extension(s), not anyone who manages or designs larger commercial work or HRBs.

Building Safety Act Changes

Within the Act there are a few defined roles in the design team. These are: The ‘Client’, the ‘Principal Designer’, ‘Designers’, the ‘Principal Contractor’ and ‘Contractors’. In a typical small scale project this might be assembled as the The owner, architect, structural engineer, the builder and any subcontractors.

The main duties of all the designers (principal and otherwise) is to not design an unsafe building. This includes during construction, use and for maintenance afterwards.

In parallel to the Building Safety Act there is also the Construction (Design and Management) Act(s) or CDM for short. This primarily addresses the health and safety of building users and those involved in the design and construction of buildings.


The Act recognises that not all construction and design can be risk free, and therefore the key H&S document from the design stage is the Pre-Construction Information document(s), or a ‘residual risk register’ if you will. Basically what is risky about the project.¬† This records the known risks with the project that haven’t managed to be designed-out (such as a long, heavy steel beam, or risks that are site-specific, such as a gas main or adjacent school access). Fairly recent changes to legislation have streamlined this to ensure risks are front-and-centre of such documentation and not lost deep in reams of paper. This means that the designers themselves need to flag any unusual risks on their drawings or separately. On an extension this might be unusually deep foundations, or awkward construction techniques or uncharacteristically long beams etc. It shouldn’t be raising more common generic risks such as tool safety or PPE as this is not usually a design risk.

These roles and names of the dutyholders (Client, Designer, Contractor etc) have been used for several years now under the CDM regs and should be familiar within the industry. However the new Building Safety Act builds upon these already established roles and uses the same terminology.

Still in the infancy of the act (2024 as of writing), this has led to a little confusion across the board. However this will become more clear as time progresses. For example there are duties under the Building Safety Act for the Principal Designer, and parallel but different duties for the Principal Designer under the CDM regulations. Confusingly, this need not be the same person or persons, but it might make sense that it is, certainly that is the way the legislation has been intended.

Risks and pitfalls for a domestic extension

If a competent and experienced team have been assembled then the new Act and it’s duties will not cause too great an issue.

On small scale works it has been common for the Designers, (Architect and structural engineer for example) to complete their design drawings and issue to the Client to see through the build with their builder by themselves. The engineer and architect only being contacted should any question or changes arise. Under the new BSA, the Principal Designer role needs to be fulfilled, and if the architect or engineer is not retained during the site stage, this role has to be assigned to either the Client, the Contractor or another 3rd party. All 3 of the Client, The Principal Designer and the Principal Contractor have to be named and counter-sign the building control compliance certificate upon completion.

While some things remain uncertain and/or professional guidance hasn’t yet covered them effectively, some of the more likely risks foreseen for small scale domestic works are therefore:

  • Contractors unwilling to be labelled as a ‘Principal Contractor’

Any contractor who has sub-contractors working ‘under’ them will be considered a Principal Contractor by default by the act, so this is more about understanding and communication upfront than anything else. Any contractor who is unaware of the recent changes should be considered with caution, what else have they misunderstood or missed? In the event that all trades are appointed to the Client directly, then there is a real risk that the Client will be considered as the Principal Contractor (with the overall responsibility for H&S on site), and in most cases this should be avoided, as their competency for site safety and co-ordination would generally be questionable.

  • Contractors unknowingly taking on design work without competency or insurance cover.

This is most likely where a trade is appointed directly and that is the extent of the project (eg a heating engineer specifying, designing and installing a new heating system). There is every chance they have missed the update of the Act and are by default acting as both Principal Designer and Principal Contractor.

Take this alternative simplified example: a roofer comes and renews a flat roof to a bathroom, part of the project includes stripping it out and adding new insulation and layers. Who has designed the roof? Is it compliant? If it goes wrong, who is responsible? Clearly in this example it is the roofing contractor who is solely responsible, which may not necessarily be an issue or a risk, but does the roofer know the risks? For more complex projects, the lines of responsibility become more complex very quickly – something the Act intended to clear up.

  • Building Control not issuing a final certificate as no Principal Designer has been appointed to sign off upon completion (and the original one is no longer involved or was never appointed)

This is a likely to be common one, and one that might lead to significant fallings out, and/or completed buildings without Building Regulations approval. If a small scale design firm, like Tom Spriggs Architect Ltd, is appointed only to do planning drawings or even planning and detailed design drawings, but then to ‘walk away’. Then who is going to be Principal Designer for the final construction stage? The law states one must be appointed, and if the designer is no longer engaged, then it will default to either the Principal Contractor or the Client. However if this is not understood early, it might well be too late to do anything about it, leaving someone having to sign off the design work without knowing what went on. The industry will adapt, and firms like TSA Ltd will begin ensuring that precautions are taken, with a competent person to take on the role for the construction period. This might be the Client, one of the Designers or the Contractor but needs to be upfront to avoid problems.

  • Designers less willing to allow specification changes, which may lead to cost rises

Builders often swap ‘like-for-like’ products to suit availability or price (often guided by their building merchants). This can continue, but better co-ordination is key. Each change needs to be run by the Principal Designer for co-ordination and inclusion into the design (before it is installed!). Without site inspections a PD will rely on the builder informing them of such changes. As this has gone on for years without notification, this will be a difficult habit to adapt. Therefore it is more and more likely that the architect will be retained for the construction phase to act as Principal Designer and to co-ordinate and oversee design changes/details, see below.

  • Architect/Designers needing to remain on the project during construction phases to act as Principal Designer, and wanting to make regular site inspections to verify co-ordination and construction. This may lead to additional time-charge fees.

Due to site changes (see above), or site solutions, it is hard or even impossible to co-ordinate all design work (which don’t forget includes construction layering, their order, and individual product specification) without either very reliable honest updates, or more likely regular site visits by the architect.

This is a small background introduction to a complex and evolving piece of legislation and is intended to expand upon client’s knowledge and understanding to help avoid pitfalls or concerns. For more exhaustive guidance, or the original legislation, additional reading will be necessary.