Planning Approval vs. Building Control: why your project needs both (and why they don't talk to each other)

At MESH Engineering, we’re often asked to explain the difference between planning approval and building control approval. And it’s a fair question. After all, they’re both run by the same local authority, both deal with construction projects, and both are crucial for getting a building out of the ground and standing up safely. So surely they talk to each other? Not quite…

Despite sounding like two sides of the same coin, planning and building control are completely separate processes, handled by different departments, with different aims, different rules, and, often, even different timelines. 

So we’ve put together some key information about these processes here for you, all in one place, to save you a heap of time googling.

Planning Approval AKA the "what" and the "where"

Planning approval is all about the big picture. It focuses on what you want to build and where you want to build it. The local planning authority looks at your proposed development in terms of how it will affect the surrounding area. 

They take into consideration the following things:

• The size and scale of the development (particularly in relation to neighbouring buildings)

• Design and visual impact 

• Use and zoning (e.g. residential, commercial, agricultural)

• Access and traffic implications

• Landscaping and tree protection

• Environmental impact and flood risk

In essence, you could say that the planning sets the stage. 

For structural engineers like us, this stage defines the parameters we have to work within: the footprint, height, form, and overall design concept. If your building exceeds a certain height, extends too close to a boundary, or alters the look of a listed property, planning officers will want to know. 

To get planning permission they’ll need to give your plans the green light.

Building Control AKA the "How"

Once you’ve got your local authority saying, "yes, you can build this", giving you planning permission, that’s when building control steps in to ask: "but can you build it safely?"

Building control approval ensures that your building complies with the technical requirements set out in the UK Building Regulations. This is where MESH Engineering really gets involved. We help demonstrate that the proposed structure is not just permissible, but robust, safe, and fit for purpose.

The key areas building control will review include:

• Structural integrity and stability (our domain)

• Fire safety (working closely with architects)

• Energy performance and insulation

• Ventilation and overheating

• Accessibility and disabled access

• Drainage and waste disposal

Our role is to prepare the detailed engineering calculations, foundation designs, and construction drawings that prove the building meets all relevant standards. It's not just about ticking boxes, it's about making sure the structure actually stands up, keeps people safe, and performs as intended over time. 

The crossover issue of drainage 

Drainage is one of those grey areas that sits across both systems. They want to know you’ve given some problem-solving thought to drainage in the planning stages, and that there’s some well-planned and realistic designs in the building control approval stage.

From a planning perspective, drainage is about environmental impact: will this development cause surface water flooding? Will it affect nearby watercourses? What happens during heavy rainfall? Planning authorities are particularly interested in sustainable drainage systems (SuDS), permeable surfaces (allowing water to drain through), and water attenuation (essentially combating floods by slowing down rainwater run-off).

From a building control point of view, it's about performance and compliance with Part H of the Building Regulations. This looks at everything practical, from pipework design to dealing with sewage. It means ensuring that internal and external drainage systems are properly sized, correctly installed, and don’t put the building at risk of damp or structural issues. 

At MESH, we often design both foul and surface water drainage systems for our clients as part of the structural work we do.

Why early engagement matters so much

Here’s where we see projects go wrong: planning approval is granted, everyone celebrates, and then the structural team is brought in too late. And it can all begin to unravel. 

Planning approval is often granted based on a conceptual design, but if structural input hasn’t been factored in early, it may turn out that parts of the proposal are impractical or non-compliant when the time comes to prepare the building control approval. That might mean structural spans that aren’t viable, insufficient wall support for proposed openings, or a foundation solution that doesn't suit the site's ground conditions.

These issues may require changes to the layout or construction method, and if they impact the building's footprint, height, or external appearance, you may find yourself back in front of the planning department with a minor amendment request. None of this is impossible to resolve, but it takes time, costs money, and can delay your build.

Bringing a structural engineer on board at the planning stage means we can spot and flag potential issues early. This gives the team the opportunity to make small, strategic adjustments, such as aligning openings with structural lines, creative solutions for potential drainage issues, or optimising the relationship between superstructure and foundation. 

These early design decisions often have a big impact on cost, programme, and buildability later on, so having structural engineering expertise on hand sooner rather than later can save you so much hassle in the long run.

Working with both systems

Planning and building control might live under the same council umbrella, but they have different remits, different teams, and different points of entry. It’s up to you (and your design team, if you’ve got one!) to join the dots.

For planning, we support you with feasibility studies and early-stage concept design, as well as site appraisals and input on structural constraints. We can also offer advice on foundations, retaining walls, and drainage risk.

For building control, we produce structural calculations and specifications, foundation and superstructure drawings, and detailed drainage design when it’s needed. We can also ensure construction details for compliance with all relevant Parts of the Building Regulations. 

Together, all these puzzle pieces form a full construction pack, enabling contractors to build with confidence and ensuring compliance every step of the way. 

To summarise: Planning permission decides if you can build it. Building control approval checks that you are going to build it properly.

So how can MESH help you?

Most projects need both of these approvals in order to get the go-ahead for building. And yet they are completely separate and fairly complex applications. 

At MESH Engineering, we work with clients across residential, commercial, heritage, and public sector projects to guide them through both systems. We help you understand what's required at each stage, avoid expensive mistakes, and ensure that your building not only gets planning permission and building controls approval but stands up to scrutiny for years to come. 

Have a project on the horizon? Let’s make sure your vision is both buildable and compliant. Get in touch to discuss how we can support your planning approval and building control journey.