Planning drawings show the council what your extension will look like and where it will sit. Building regulations drawings show a builder and a building control officer how it will be constructed, in enough technical detail to prove it meets the standards. They are two different packs, for two different approvals, and most extensions need both. Even a project that needs no planning application still needs building regulations sign-off.
This guide explains what each set contains, who reads it, which comes first, and what changes if you are building under permitted development.
TL;DR
- Planning drawings cover appearance, size, position and impact on neighbours. Building regs drawings cover structure, insulation, fire safety, drainage and ventilation.
- One approval never replaces the other. Planning concerns appearance and land use, building control concerns safety, health and comfort.
- Planning drawings usually come first. Technical drawings are often produced after consent, because the planners may ask for changes.
- Permitted development removes the planning application, not the building regulations or the Party Wall Act.
- A Full Plans building control submission needs detailed drawings, calculations and a specification. A Building Notice needs no plans at submission but gives you no formal approval decision.
Table of Contents
- The core difference in one minute
- What planning drawings show
- What building regulations drawings show
- Side-by-side comparison
- Which comes first?
- Do you need drawings under permitted development?
- When building control approval is needed
- Full Plans or Building Notice: how drawings change
- What happens at the end
- Common mistakes with the two drawing sets
- Our perspective
- Let us handle both sets of drawings
- FAQ
- Sources
The core difference in one minute
Think of it as "what" versus "how".
Planning asks: is this development acceptable on this site? The council looks at the height, depth, materials, the relationship with neighbouring homes and the street. Building regulations ask: will this building be safe, healthy and energy efficient once it is built? The officer looks at foundations, beams, insulation, escape routes, drainage and ventilation.
A planning drawing can be accurate and still tell a builder almost nothing about how to construct the wall. A building regs drawing can be perfectly detailed and say nothing about whether the council will like the roof shape. You need both, produced in a sensible order, and ideally by one team so the two sets agree with each other.
What planning drawings show
For a householder extension, councils generally ask for a standard set. Derby City Council's guidance is a typical example. It lists a location plan, a block plan, existing and proposed floor plans, a roof plan, elevations and sections, plus site photographs. The council also says the drawings must be accurate and detailed enough to be accepted and validated.
In practice that means:
- Location plan: your property outlined in red on an Ordnance Survey base, so the council knows exactly which site is involved.
- Block plan: the house, the extension, boundaries and neighbouring buildings, drawn to scale.
- Existing and proposed floor plans: what is there now and what you want, side by side, so the change is easy to read.
- Elevations: every face of the house as it will look, showing windows, doors, roof pitch and materials.
- Sections and roof plan: heights, ridge lines and how the new roof meets the old.
These drawings are a communication tool for a planning officer, neighbours who comment, and sometimes a committee. They need to be clear and to scale. They do not need to show the depth of the foundations or the thickness of the insulation.
What building regulations drawings show
Building regs drawings are the construction detail. Homebuilding & Renovating explains that they demonstrate compliance with standards including structure, fire safety, security, electronic communications and thermal efficiency.
A typical set for a rear or kitchen extension includes:
- Foundation details: type, depth and width, usually informed by the ground conditions and nearby trees.
- Structural information: steel beam and lintel positions, with the structural engineer's calculations alongside.
- Wall, floor and roof build-ups: each layer annotated with its insulation and how it achieves the required thermal performance.
- Fire safety: escape routes from upper floors, fire-resisting construction where needed, smoke and heat alarm positions.
- Drainage: where new foul and surface water pipes run, and how they connect to existing drains or sewers.
- Ventilation: extract fans, trickle vents and the airflow expected in new rooms.
- Electrical and security details: where relevant, such as window and door standards.
- Specification notes: materials and workmanship standards, shown on the drawings or in a separate document.
These drawings are read by building control and by the builder on site. The more complete they are, the fewer surprises and variations arise during construction.
Side-by-side comparison
| Planning drawings | Building regs drawings | |
|---|---|---|
| Question answered | Is the development acceptable? | Is it built safely and efficiently? |
| Reader | Planning officer, neighbours | Building control officer, builder, engineer |
| Focus | Size, position, appearance, materials | Structure, insulation, fire, drainage, ventilation |
| Level of detail | Scaled plans and elevations | Construction details, notes, calculations |
| Typical timing | First, before work starts | After planning consent, before work starts |
| Needed under permitted development? | No application, but see below | Yes, almost always |
Which comes first?
Usually planning. Homebuilding & Renovating notes that after planning approval the focus shifts to detailed construction drawings. It also says technical drawings are often commissioned after consent, because planners may require design changes or reject the application.
The logic is simple. If you pay for a full technical pack and the council then asks you to reduce the depth or change the roof, part of that work has to be redone. Sequencing the work avoids it.
There is one nuance. A good designer thinks about construction while drawing the planning set. A beam that will be needed, a drain that cannot move, or a roof that cannot be built economically should be spotted early. That is the main benefit of having design and build under one team: the planning drawings are drawn by people who know what the builder will face.
If you are budgeting, our guide to extension planning drawings and the two packs covers how to plan for both sets from the start.
Do you need drawings under permitted development?
This is the question many people ask, and the answer has two halves.
Planning side. In England, permitted development rights grant planning permission for certain works without a planning application, subject to conditions and limitations. So no planning application and no planning drawing pack is required by law. A proposal must meet all the limitations and conditions under each relevant class to benefit.
The Planning Portal's single-storey extension guide gives the standard limits. A rear extension can go up to 4 metres beyond the rear wall of a detached house, or 3 metres for any other house. Larger limits of 8 metres and 6 metres respectively may be available outside designated land, but require prior approval. Extensions and other buildings must not cover more than 50% of the land around the original house.
In practice, you still want scaled drawings. You need them to check you are within the limits, to brief a builder, and to price accurately. Many owners also apply for a lawful development certificate, which gives written confirmation from the council that the work is lawful. That application normally needs accurate existing and proposed plans and elevations, much like a planning application. It is optional, but it is useful evidence when you later sell. See our guide to permitted development extension rules for the limits in detail.
Building regulations side. Permitted development does not remove other obligations. GOV.UK's technical guidance states that rights do not remove duties under building regulations and the Party Wall Act. So the technical drawing pack is still needed.
Permitted development rights also do not apply everywhere. Householder rights do not apply to houses created through certain commercial-to-residential rights, or to flats. Conservation areas and other designated land bring tighter limits too, which our conservation area extension guide explains.
When building control approval is needed
Building control approval must be obtained before work on projects such as extensions begins, as West Northamptonshire Council's building control guidance puts it. The rules are the same whether or not planning permission was needed.
A word on jurisdiction: planning rules differ between England, Scotland, Wales and Northern Ireland, and the permitted development figures above are for England. Our work is in the West Midlands, so that is the framework this guide assumes.
Full Plans or Building Notice: how drawings change
The route you choose for building control decides how many drawings you need at the start.
Full Plans. A detailed submission that is reviewed before construction and, if approved, receives a formal approval notice. It needs comprehensive architectural drawings, specifications and plans. In practice that means plans, elevations and sections, structural engineer's calculations and a location or block plan, with specifications either on the drawings or separate, as Homebuilding & Renovating describes.
Building Notice. Suited to small domestic works, it requires no plans at submission and results in no formal decision. It cannot be used for non-residential work, certain work within three metres of a public sewer, or buildings subject to fire safety legislation.
For a larger extension such as a kitchen-diner with structural openings, a double-storey addition or a wrap-around, Full Plans is the sensible route. You get a decision before work starts, and the builder works from approved drawings. A Building Notice leaves the detail to be agreed on site, which is hard to manage on anything with steelwork or drainage changes.
You can also choose between the local authority and a private approved inspector. Our guide to building control versus an approved inspector sets out the differences.
What happens at the end
Your building control body inspects at key stages: foundations, drainage, structure, insulation and completion. You will usually get a completion certificate within eight weeks of completing the work, provided it complies.
Keep that certificate safe. Buyers' solicitors ask for it when you sell, and its absence can hold up a sale. Councils also have longer to act on non-compliant work than they once did: section 39 of the Building Safety Act 2022 extended the enforcement periods, which previously stood at 12 months for notices and two years for prosecutions. Doing it properly the first time is the cheaper route.
Common mistakes with the two drawing sets
- Treating planning consent as building approval. It is not. Work started on planning drawings alone has no building control sign-off.
- Buying technical drawings too early. If the planning outcome is uncertain, a full technical pack can be wasted effort.
- Drawings that disagree. If the planning set shows a window the technical set omits, the builder will not know which to follow. One team drawing both prevents this.
- Forgetting the neighbours. The Party Wall Act applies separately. Shared walls and nearby excavations are common triggers, as covered in our semi-detached extension guide.
- Changing the design mid-build. If you change the layout after approval, the drawings and sometimes the approvals need updating.
Our perspective
Most homeowners we meet assume there is one set of plans. There are two, and the gap between them is where projects go wrong: a design that planning approved but nobody has worked out how to build, or a technical pack drawn by someone who never saw the planning scheme.
That is why we run design, planning, building regulations and construction as one managed process with one team. The person drawing your planning set knows what the builder will need, so the technical drawings follow naturally and nothing is redrawn.
We also give realistic budget guidance before any site survey, so you know what the drawings, approvals and build are likely to involve before you commit. And because we work locally across Birmingham, Solihull and the surrounding West Midlands, we can supervise closely and respond quickly during the build.
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Let us handle both sets of drawings
If you would rather not coordinate designers, planning consultants, engineers and builders yourself, that is what we do. Extension Kings designs and builds bespoke extensions across the West Midlands, including single-storey, double-storey, kitchen, rear, side-return, wrap-around and over-garage extensions. We manage planning and building regulations from first consultation to handover.
To discuss your project, start at Extension Kings. If you are considering a garage conversion upward, our page on over-garage extensions and West Midlands costs is a good next step.
FAQ
What is the difference between planning drawings and building regulations drawings?
Planning drawings show the council what the extension looks like, how big it is and where it sits. Building regulations drawings show how it is constructed, covering structure, insulation, fire safety and drainage. They go to different bodies for different approvals.
Do I need building regulations drawings if I have permitted development?
Yes. Permitted development replaces the planning application, not building regulations. GOV.UK's guidance confirms that these rights do not remove building regulations or Party Wall Act obligations, so you still need technical drawings for building control.
Can I use my planning drawings for building control?
Not on their own for a Full Plans application. Planning drawings lack construction detail such as foundations, beam sizes and insulation build-ups. Technical drawings usually build on the planning set, adding detail and engineer's calculations.
Which should I get first, planning or building regs drawings?
Planning drawings first in most cases, because planners can request changes or refuse. Once consent is granted, the technical pack is produced and submitted to building control before work starts.
Do I need drawings for a lawful development certificate?
Yes, typically. The council needs accurate existing and proposed plans and elevations to confirm that the work falls within permitted development. The certificate is optional but gives you written proof of lawfulness.
Sources
- An expert guide to building regulations drawings, Homebuilding & Renovating
- Building control: Frequently Asked Questions, North Norfolk District Council
- Planning Drawing Guidance, Derby City Council
- When is permission required? GOV.UK
- Permitted development rights for householders: technical guidance, GOV.UK
- Single-storey extension mini guide, Planning Portal
- Before you apply for building control, West Northamptonshire Council
- Building control FAQs, Oxford City Council
- Building regulations approval: How to apply, GOV.UK
- Building Regulations Enforcement Periods: Section 39, Boyletts Law