Building Regulations Guide

There has been a lot of serious changes within the Building Regulations and Building Control over the last 5 years, this will impact people differently. Homeowners extending, builders, developers etc all face new challenges and responsibilities.

Building Regulations are the legal standards that set minimum requirements for the design and construction of buildings in the UK. They cover areas such as structure, safety, energy efficiency, fire protection, ventilation, and accessibility to ensure buildings are safe, sustainable, and fit for use. Building Control is the system that checks these rules are followed. It involves local authority or private inspectors reviewing designs, inspecting work on site, and issuing approval or completion certificates. Together, regulations set the rules, and building control enforces them, ensuring that construction work meets required standards before, during, and after completion.

1 – Detailed Building Regulations drawings are created by the principal designer aka architect, architectural technician.

2 – The detailed drawings, specification and any required consultant information are submitted to building control and checked for compliance. Amendments or supporting information may be requested and then approved via full plans approval.

3 – Building Control are then notified by the builder who takes on the role of principal designer and principal contractor throughout the build in line with the duty holder roles

4 – Building Control Officers will by required to visit the site and sign off key stages

5 – The building certificate is issued once all key stages are signed off, along with gas and electric certificates.

You can forgo the full plans submission and build under a building notice, this replies purely on the builder’s knowledge and onsite inspections. This increases risk and only suitable for very basic low risk, low-cost projects.

Construction of any new building such as houses, outbuildings etc

Extending buildings will generally require Building Control, this covers things like rear and side extensions, roof extension such as dormers.

Alteration and conversion of buildings such as lofts, garages and barns removing any structural or thermal elements.

Installation or extension of services and fittings such as drainage connections, utility connections, solar panels, changes to heating appliances. Windows require either FENSA approved installer or building control

Certain changes of use also trigger Building Control like changing type, function or occupancy and changing a shop to residential.

Any alteration to public buildings/site or places of work

There are low risk buildings and structure that can be done without Building Control applying the Regulations. These are typically small, temporary or not occupied such as:

Detached single storey buildings with floor area’s under 30Msq, more then 1M from a boundary, without sleeping accommodation and primarily non-combustible material. Could be garden room, garage, sheds. Note adding fixed heating will often trigger building control due to increased fire risk and potential loss of energy efficiency.

Building under 15Msq can be heated and more habitable, check with local building control before commencing

See the Government Building Regulations Approval for more information

Building regulations are UK legal standards that set minimum requirements for how buildings are designed and constructed, covering safety, health, energy efficiency, accessibility, and fire protection. They apply to new buildings, extensions, alterations, and installation of services. The compliance to the approved documents must be demonstrated via technical design on Building Regulations drawings and or onsite through the build process and documented by the duty holder principal designer.

Compliance is demonstrated using Approved Documents, which provide technical guidance. The main sections are:

A – Structure: Ensures buildings are structurally safe and stable.

B – Fire safety: Sets requirements to prevent fire and enable safe escape.

C – Site preparation and resistance to contaminants and moisture: Protects buildings from damp, gas, and ground contaminants.

D – Toxic substances: Controls the use of hazardous materials in construction.

E – Resistance to sound: Limits noise transmission between buildings or rooms.

F – Ventilation: Ensures adequate airflow for health and comfort.

G – Sanitation, hot water safety and water efficiency: Covers plumbing, water supply, and hygiene.

H – Drainage and waste disposal: Sets standards for foul and surface water drainage.

J – Combustion appliances and fuel storage systems: Ensures safe installation of boilers, stoves, and fuel systems.

K – Protection from falling, collision and impact: Covers stairs, guarding, and safety glazing.

L – Conservation of fuel and power: Sets energy efficiency requirements.

M – Access to and use of buildings: Ensures buildings are accessible to all users.

O – Overheating: Limits overheating risk in buildings.

P – Electrical safety: Ensures safe installation of electrical systems.

Q – Security: Improves resistance to unauthorised access in dwellings.

R – Infrastructure for electronic communications: Requires provision for broadband connectivity.

S – Infrastructure for electric vehicle charging: Requires EV charging provision.

T – Toilet accommodation: Sets standards for provision of toilets in buildings.

There is a significant shift in the process, document driven by net-zero carbon target and post Grenfell safety reforms

Building Safety Act 2022 – complete overhaul of safety regulation and accountability, this has changed the responsibility for compliance to the duty holder / principal designer role.

Part L upgrades + Future Homes Standard – massive tightening of energy/carbon rules, this has increased insulation values/costs, push towards electrification and renewables

Fire safety reforms (Part B + Fire Safety laws) – stricter requirements and enforcement

New Parts O, S + updated F – overheating, EV charging, and ventilation introduced/expanded

Stronger compliance regime – more inspections, documentation, and legal responsibility

This is a very key change that has increased the responsibility for homeowners to appoint a competent person as both principal; designer and contractor throughout the build phase. It causes a lot of confusion as builders and homeowners don’t understand the design phase principal designer hands over responsibility to the client and builder. So, unless the architect or designer is involved through the build process and retain the principal design role the ownness is on the builder. More concerning is building control will not sign off any project without the principal designer signing off the onsite compliance to building control. This requires a full document of the golden thread of relevant information, changes, notes and photographic evidence by a competent person. For a full guide see link.

This does not account for the CDM regulations 2015 and further confuses the roles of Principal Contractor and Designer. Though the titles are the same the responsibilities and role changes significantly with duty holder under the building act 2022 being responsible for Building regulations compliance. CDM Duty Holders are more responsible for health and safety throughout the build process.

Your architect*, competent design technician or technologist are the essential part of producing Building Regulations drawings. There will often be the requirement for specialist consultants who loosely relate to the approved document sections.

Structure (Part A) will often require a structural engineer to design, calculate and provide details for altering structural walls, roofs, design foundations, beams, columns etc

Conservation and fuel and power (Part L) This can trigger an energy assessor for SAP (Standard Assessment Procedure) calculations. They will design the insulation requirements against the heating source to hit efficiency and heat loss targets.

For more complex projects like new buildings and commercial you would need

Mechanical Engineer (Part P, O, F, L) They would design electrical elements, ventilation, heating etc

Acoustic Engineer (Part E) design resistance to the passage of sound, this can be between flat or building to building. Any commercial activities that could cause noise pollution

Drainage/Civil Engineer (Part H Drainage) are necessary for dispersing and removal of rainwater and foul waster from site.

Fire Engineer / Officer (Part B Fire safety)

There are several more for unique circumstances, sourcing and collation of information is the responsibility of the principal design aka architect or designer prebuild and builder during the build.

*this implies architects are competent but do ensure they have the relevant post grad experience as some are more design and planning led experts.

The CDM Regulations 2015 (Construction Design and Management) set out legal duties to ensure health, safety, and welfare are properly managed on construction projects in the UK. They apply to all construction work and place responsibilities on clients, designers, and contractors. Key requirements include appointing duty holders (such as a Principal Designer and Principal Contractor), planning work safely, managing risks through design, and providing clear information. The aim is to reduce accidents by embedding safety throughout the project lifecycle.

Local Authority Building Control is provided by the local council and acts as the official regulator, with legal powers to enforce Building Regulations and take action if rules are broken. Private inspectors (now called Registered Building Control Approvers) are independent companies hired by the client to check compliance. They carry out the same inspections but cannot enforce the law directly and must refer serious issues to the local authority.

In practice, local authorities combine inspection and enforcement, while private inspectors offer a more flexible, customer-focused service. Both ensure buildings meet regulations, but they differ mainly in authority, accountability, and who appoints them.

One consideration is the impartiality of the local authority and local knowledge, they are a recognised authority non for-profit council employee. Private inspectors are in business to earn profit (more expensive) and often recommended by builders regularly which could lead to confliction of interest. Being in business does mean a level of customer service obligation that the local authority does not need.

Our recent experience across the UK has identified some real pain points for our clients.

Duty Holder sign off – Some builders have refused to sign off and take responsibility for the onsite Principal Designer role. This has left some projects without signoff and clients unsure who needs to sign it.

Not signed off – if the building certificate is not issued then the home insurance will not be valid, it is essential all supporting documentation is provided on time for this to gain the building certificate.

Build over agreements – This common oversite of the legal drainage requirement can lead to big delays on site. The water authority will need to confirm H4 compliance or if a build over agreement is required. H4 compliance means building control can sign off the work, build over agreements need technical drawing and sometimes engineer support. In extreme case building works cannot be achieved. Overcome this by inspecting the drains early on and contacting the water authority as far in advance as possible. Some architecture practices do this, and some don’t (we do)

Building notice compliance failures – Some builders will persuade clients they can build without drawings and full plans support. If this is backed up by a very detailed quotation, full due diligence regarding drains, structure, up to date insulation knowledge etc but most builders are excellent at building and not so good at management and document control which is now essential.

Not Planning approved – Building control approval does not mean planning approval and unlawful building work could require changes, see our planning guide

Working off the wrong plans – Building Regulation drawings will have revisions on them and the full plans approval will reference the revision that was approved. Ensure your builder is working from them and documenting any deviations.

Collation of consultant’s information – in some cases Building Regulations drawings are issued with consultant information like Structural Engineering. This must not be assumed to tie in with the drawing details and ownness is on the builder to apply it.

On-Site-Design – The builder will sometimes have better methods and materials that deviate from the approved plans. This is fine but if they are noted, approved by building control and documented properly for sign off.

Understanding the limit of Building Regulation drawings – Most Building Regulations drawing packages are aimed at compliance, they do not form a construction or Working Drawing pack. The builder must measure, check and apply on-site-design along with this and precheck the variable elements. Homeowner, developers and builders must know what level of detail and responsibility the drawing package assumes.