Planning Permission vs Building Regulations: What Do You Need Before Renovating?

Planning permission and Building Regulations are often discussed together, which makes it easy to assume they are two stages of the same approval. They are not.

Planning permission considers whether development is acceptable. Building Regulations deal with how building work is designed and constructed to meet applicable technical standards.

A renovation may need both. It may need Building Regulations approval without needing a planning application. In some cases, work can proceed under permitted development but still needs to comply with Building Regulations. There is a third issue that often becomes relevant during extensions and major renovations: structural engineering. Structural calculations are not planning permission and are not a separate substitute for Building Regulations approval. They provide technical evidence and design information where the work affects load-bearing parts of the building and may form part of the Building Control submission.

The distinction became particularly important on AC Design Solution’s real Finchley Road, South Hampstead project. The period property involved earlier work carried out without the necessary planning consent, a new 38 sqm single-storey extension and significant internal structural alterations. Planning, technical compliance and structural design all had to be addressed, but they solved different problems.

This guide explains those differences and what homeowners should check before starting a renovation in England.

Planning Permission vs Building Regulations: The Simple Difference

The Planning Portal summarises the distinction clearly: planning deals with whether development should be allowed, while Building Regulations set standards for the design and construction of buildings. Many projects require separate approval under both systems. For a homeowner, the easiest way to think about it is:

Planning permission is therefore largely about what development can take place. Building Regulations are about how the work is designed and constructed.

GOV.UK expressly confirms that Building Regulations approval is different from planning permission and that a project may need both.

What Does Planning Permission Actually Control?

Planning permission is administered by the Local Planning Authority, normally the relevant council. The authority considers the development in its planning context. Depending on the proposal, this can include its size and appearance, effect on neighbouring properties, relationship to the street, use of the land or building, access and the wider environment.

For a house extension, the planning drawings might show the existing and proposed floor plans, elevations, roof form, dimensions and materials.

Those drawings help the planning officer answer questions such as:

Will the extension be too dominant in relation to the existing house? Could it significantly affect a neighbour? Is its design appropriate to the property and area? Does it comply with relevant local and national planning policy?

AC Design Solution’s house extension drawings service covers planning drawings as well as the later technical information needed for Building Control. Its current guidance also distinguishes planning drawings from Building Regulation drawings rather than treating them as interchangeable.

Receiving planning permission means the planning authority has accepted the development subject to the decision and any conditions.

It does not mean Building Control has checked how the extension will be constructed.

What Do Building Regulations Control?

Building Regulations address technical standards. GOV.UK identifies construction, extensions and many types of alterations as work that can require Building Regulations approval. Relevant requirements can include structural safety, fire safety, ventilation, energy efficiency and other aspects of building performance.

This means a Building Regulation drawing package generally contains much more construction information than a planning set.

For example, planning drawings may show the location and overall dimensions of a rear extension. The Building Regulation drawings then develop information such as wall and roof build-ups, insulation, foundations, drainage, ventilation and structural coordination where required.

Building Control is therefore not reconsidering whether the extension looks appropriate in the street. It is assessing whether the relevant technical requirements have been addressed.

This is why planning approval but no Building Regulations approval can still leave an important part of a project unresolved.

Real Project: How the Difference Applied at Finchley Road

Finchley Road in South Hampstead is a useful example because planning, Building Regulations and structural engineering all arose within the same renovation.

AC Design Solution’s project evidence records a period property where previous owners had already carried out building work without the necessary planning consent. The subsequent project involved resolving the planning position, adding a 38 sqm single-storey rear extension and undertaking major structural alterations.

Those activities can be separated into three different questions.

1. Was the development acceptable in planning terms?

Earlier work had to be addressed through the planning process, while the new extension also had its own architectural and planning considerations. That is the planning question.

2. How should the extension and renovation be technically constructed?

The new work required detailed construction information and coordination with Building Regulations requirements. That is the Building Regulations question.

3. How could load-bearing walls be altered safely?

The renovation included the removal of load-bearing walls. The engineering team calculated where structural support and steel beams were required so that loads could be transferred safely. That is the structural engineering question.

The project evidence supplied by AC Design Solution states that retrospective planning applications were approved, structural steelwork supported the revised layout, and Building Control inspections formed part of the compliance process. It does not establish that the three processes were one approval; they were coordinated parts of the same project.
That distinction is exactly what homeowners need to understand.

Where Does Structural Engineering Fit?

Structural engineering is often confused with Building Regulation drawings because structural calculations are commonly submitted to Building Control. But the two are not identical.

A Building Regulation package considers the wider technical compliance of the project. Structural engineering concentrates on the safety, stability and load-bearing performance of the structure.

If a renovation involves removing a load-bearing wall, installing a large opening, altering a roof or designing foundations for an extension, the engineer may need to prepare calculations and structural drawings.

AC Design Solution’s structural drawings and calculations cover components such as beams, foundations, floors, roofs and structural connections, with the resulting information used to support Building Control assessment where required. A useful way to think about the relationship is:

Planning: Can we make this change?
Structural engineering: How will the changed structure safely carry its loads?
Building Regulations: Does the overall technical design and construction meet the applicable requirements?

On a well-coordinated project, those questions inform one another without being confused as one approval.

If I Have Planning Permission, Do I Still Need Building Regulations?

Often, yes. The fact that planning permission has been granted does not remove a separate Building Regulations requirement.

For example, imagine a homeowner receives planning permission for a new rear extension. The planning decision may confirm that the proposed size and appearance are acceptable. The builder still needs technical information addressing how the foundations, external walls, roof, insulation, drainage, ventilation and structural openings will work.

Planning drawings alone generally do not contain enough construction information for that purpose. AC Design Solution’s current extension guidance makes the same distinction: planning approval and Building Regulations are separate systems, and planning drawings do not provide the technical information Building Control needs to assess construction.

So planning permission should not be treated as permission to build without considering Building Regulations.

What If My Project Does Not Need Planning Permission?

This is another common source of confusion. Some residential work can fall within permitted development rights, meaning a full planning application is not required if the proposal satisfies the relevant conditions and the rights apply to that particular property.

That only answers the planning question. It does not automatically remove Building Regulations requirements.
For example, a qualifying loft conversion or house extension might proceed under permitted development while still requiring structural design and Building Control involvement.

Before relying on permitted development, the property and proposal should be checked carefully. Conservation areas, Article 4 Directions, flats, previous development and other circumstances can change the planning position.
AC Design Solution’s permitted development checker can be used as an initial screening tool, while the Planning Portal provides the current national planning framework and guidance.

Can You Need Building Regulations Without Planning Permission?

Yes. Internal alterations provide a common example. Removing an internal load-bearing wall in an ordinary unlisted house may not require a planning application purely because the internal layout is changing.

But the structural alteration can still need Building Regulations approval because the stability of the building is affected.
Planning Portal specifically notes that some internal alterations may require Building Regulations approval even where planning permission is not needed. The same principle can apply to other types of work.

That is why the question should never simply be: “Do I need permission?” Instead ask: “Which approvals or technical requirements apply to this particular work?”

What if I Have Planning Approval but No Building Regulations Completion Certificate?

Planning permission does not substitute for a Building Regulations completion record. For applicable work, Building Control is involved through the technical approval and inspection process. Under the Full Plans route, GOV.UK states that a completion certificate will usually be provided after completion where the work complies with the relevant requirements.

If you are reviewing an older renovation and cannot find a completion certificate, first establish what Building Control application was made and what records exist.

Do not immediately assume that the absence of a certificate proves that the construction is unsafe or that no Building Control process ever took place. The records need to be checked.

If work was carried out without the necessary Building Regulations approval, a different process such as regularisation may be relevant in eligible circumstances. GOV.UK states that regularisation is a retrospective Building Regulations route available through local-authority Building Control for qualifying work carried out after 11 November 1985.
That is separate from retrospective planning permission.

Planning Permission and Building Regulations for an Extension

A typical house extension demonstrates why both systems often matter. At the planning stage, the drawings establish the proposed footprint, height, elevations, roof form and relationship with the original house and neighbours.

Once the planning position is established, technical design develops the construction. The Building Regulation package might then address foundations, wall and roof construction, insulation, drainage and ventilation. Where the new opening into the existing house is structural, an engineer may design the beam or structural frame.

The three sets of information should coordinate. If the structural beam requires more depth than the architectural design allowed for, the ceiling or opening may need to change. If the roof build-up changes, the approved external dimensions may need to be checked. If drainage affects foundation design, the architectural and engineering information may both need revision.

This is why treating planning, structural engineering and Building Regulations as separate appointments with no coordination can create avoidable redesign.

What Documents Might You Need?

The exact documents depend on the project rather than a universal checklist. For a typical extension or substantial renovation, the project may involve planning drawings and supporting planning documents, detailed Building Regulation drawings, structural calculations where load-bearing work is involved and specialist information where required by the design.

A useful comparison is AC Design Solution’s guide to planning drawings vs Building Regulation drawings, which shows the different level and purpose of information within the two packages. The important point is not how many drawings you have.

It is whether the correct information has been prepared for the correct approval process.

Which Comes First: Planning Permission or Building Regulations?

For projects that need planning permission, detailed Building Regulation design is often developed after the planning position is sufficiently established. There is a practical reason for this.

A planning authority may require changes to the size, appearance or layout of a proposal. Developing every construction detail before those planning matters have been settled can create unnecessary technical redesign.

That does not mean structural or Building Regulations considerations should be ignored during planning.
A design still needs to be feasible. If a large opening, unusual roof or complex foundation arrangement is fundamental to the proposal, early structural input can identify whether the architectural concept is realistic before it is submitted.
The best workflow is therefore not:

Planning first, think about structure later.
It is:

Develop a feasible architectural proposal → establish the planning route → coordinate structural and technical design → obtain the relevant Building Control approval → construct and inspect.

Which Building Control Route Applies?

For ordinary domestic projects in England that are not higher-risk building work, Building Regulations approval can generally be dealt with through the local authority or a private Registered Building Control Approver. GOV.UK confirms that Registered Building Control Approvers is the current private-sector Building Control route.

For eligible projects, common routes include Full Plans and Building Notice. GOV.UK describes Full Plans as the more thorough route, with technical information assessed before a formal decision. A Building Notice is intended for smaller projects and does not provide the same formal plans approval in advance. The appropriate route depends on the work.
For substantial extensions or renovations involving structural coordination, detailed technical drawings before construction can provide a clearer basis for the owner, contractor and Building Control team.

Common Mistakes Homeowners Make

One of the most common mistakes is assuming that the council has “approved the project” because a planning decision notice has been issued. That is only the planning approval.

Another is assuming that permitted development means no regulatory approvals are needed at all. A third is asking a structural engineer to design a beam and assuming the structural calculation alone covers every Building Regulations requirement for the renovation.

Finchley Road shows why those assumptions can create problems. One property could simultaneously have an existing planning issue, a new planning proposal, structural alterations and Building Regulations requirements. Each issue needed to be identified and dealt with under the appropriate process.

What Should You Check Before Starting a Renovation?

A practical sequence is:

1. Define exactly what you want to change. An extension, loft conversion and internal wall removal can trigger different requirements.

2. Check the planning route. Establish whether the work needs planning permission, falls under permitted development or is affected by additional controls.

3. Review the existing property. Check whether earlier alterations match the available planning and Building Control records.

4. Identify structural work early. Load-bearing walls, roof alterations, large openings and foundations may require engineering input.

5. Develop the Building Regulation package. Coordinate the architectural technical drawings with structural and other specialist information.

6. Confirm the correct Building Control process before construction. Do not rely solely on the planning decision notice.

This sequence is particularly valuable for older London properties, where previous work may have changed the building long before the current renovation was proposed.

Do You Always Need Both?

No. Some projects need planning permission and Building Regulations approval. Some need Building Regulations but not a planning application.

Some may not require either formal application, although other requirements can still apply. And some properties may also need additional permissions or procedures, such as Listed Building Consent or Party Wall notices, depending on the building and proposed work.

There is therefore no reliable answer based only on the project name. Two “rear extensions” can have different planning circumstances. Two internal renovations can involve completely different structural work. The approvals should be established from the property and proposal rather than from a generic checklist.

Planning a Renovation in London?

Planning permission, Building Regulations and structural engineering work best when they are coordinated from the beginning. AC Design Solution’s architectural services cover the project lifecycle from feasibility and planning applications through to technical design and Building Control, while structural engineering can be coordinated where the proposal affects load-bearing elements.

The Finchley Road project demonstrates the practical advantage of that approach: existing planning issues, a new extension, major structural changes and technical compliance were considered within the same renovation rather than as unrelated pieces of paperwork.

If you are unsure whether your renovation needs planning permission, Building Regulations approval, structural calculations or a combination of all three, contact AC Design Solution for a project-specific review.