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Planning & Permissions

Everything you need to sort before a single brick is laid

17 tasks in this phase

Five-step planning permission process: check permitted development, prepare drawings, submit application, 8-week waiting period, decision notice received
1
Do You Need Planning Permission for Your Extension?
How to tell whether your extension needs a planning application or falls under permitted development. Covers the two routes, when PD rights don't apply, and how to check your property.
Free
The seven permitted development conditions for UK house extensions: property type, depth limit, overall height, eaves height, curtilage 50%, materials, and exclusions
2
Permitted Development Rules for Extensions
The exact PD limits for single-storey rear extensions in England. Depth, height, curtilage, materials, and how to confirm your extension qualifies with a £274 Lawful Development Certificate.
Free
Infographic showing the Planning Portal's role as an intermediary between homeowners and local council planning departments, with the service charge and submission flow
3
The Planning Portal: What It Is and How to Use It
What the Planning Portal does, what it costs (£91 service charge), and how it differs from your council's planning website.
Free with email
Six-stage architect pipeline infographic showing the journey from initial consultation through outline drawings, detailed plans, planning submission, building control documents, and BC submission, with typical fees and timeline at each stage
4
Finding an Architect for Your Extension
How to find, appoint, and manage an architect for your extension. Covers fees (typically £1,500 – £2,500), what each stage costs, and the questions to ask before you commit.
Free with email
The 42-day prior approval timeline showing submission, 21-day neighbour consultation window, council assessment period, and decision outcomes
5
Prior Approval for a Larger Home Extension
The prior approval process for extending beyond standard PD limits (up to 6m or 8m). Covers the £249 fee, 42-day timeline, neighbour consultation, and what to do if refused.
Free with email
Side-by-side comparison of a 1:1250 location plan and a 1:200 site plan, annotated with the required elements: red line boundary, north arrow, scale bar, and OS licence number
6
Purchasing OS Maps for Your Planning Application
Where to buy the Ordnance Survey maps required for your planning application, which scales to order, and how to avoid the location plan errors that invalidate 22% of submissions.
Free with email
Planning application timeline from submission to decision: validation, neighbour consultation, site visit, officer assessment, 8-week determination, decision notice
7
Submitting a Planning Application: The Full Process
How to submit a householder planning application in England. Covers the £548 fee, required drawings, Planning Portal submission, the 8-week decision timeline, and what to do if refused.
Free with email
Process infographic showing the structural engineer's involvement across the extension project lifecycle, from initial calculations through mid-build revisions to building control sign-off
8
What Does a Structural Engineer Do for Your Extension?
Your structural engineer calculates the steels, foundations, and load paths that stop your extension falling down. Expect to pay £500 – £1,500 for initial calcs, plus £45 – £135 per revision.
Free with email
Timeline showing the neighbour conversation process from informal doorstep chat through council consultation to planning decision
9
Talking to Neighbours About Your Extension
How to discuss your extension plans with neighbours before submitting planning. Covers what to say, what not to say, and how to handle objections.
Free with email
Triage diagram of the four channels a neighbour can act through against an extension, showing which can stop, delay, or carry no weight
10
Can a Neighbour Stop Your Extension? What They Can and Can't Do
An objection is not a veto. How to tell a toothless complaint from a real legal lever: planning objections, the Party Wall Act, right to light, restrictive covenants, and oversailing trespass.
Free
Party wall timeline flowchart showing notice periods, 14-day response window, consent and dissent paths, and minimum wait before construction can begin
11
Party Wall Agreements: What You Need to Know
The Party Wall Act 1996 can delay your extension by months if you don't handle it early. Covers when it applies, the notice process, costs (nothing to thousands if disputed), and how to protect yourself.
Free
Timeline infographic showing the building control application process from document preparation through to conditional approval, with realistic durations at each stage
12
Building Control: How to Apply and What to Expect
Building control is separate from planning permission and costs £300 – £900 for the plan check alone. Here's how to apply, what the documents contain, and realistic timescales.
Free with email
Infographic dashboard showing extension cost breakdown by category with proportional bars, total cost range, and contingency buffer highlighted
13
Budgeting for Your Extension: What It Really Costs
Learn how to budget properly for a single-storey extension, why builder quotes cover only part of the total, and how to protect yourself from overruns.
Free with email
Infographic showing the seven building control inspection stages for a UK single-storey extension: commencement visit, foundations, drainage, oversite and DPC, structure and roof, pre-plaster, and completion
14
What Building Control Inspects at Each Stage
Your BCO checks foundations, drainage, structure, and fire safety across 5-7 visits. Know what they look for so you can hold your builder accountable.
Free with email
Process infographic comparing the five main UK extension funding routes across speed to draw down, indicative rate band, secured vs unsecured, FCA protections, and the build size each route suits best
15
Financing Your Extension: The Real Options for Homeowners
How to pay for a UK extension. Further advance vs remortgage vs second-charge vs personal loan, MCOB stress test, Section 75 deposit protection, and the products to avoid.
Free with email
Three-layer regulatory stack diagram showing the bottom layer Building Act 1984 plus Building Regulations 2010 statutory instrument, the middle layer Approved Documents A through T plus AD 7 official guidance, and the top layer BS, EN, and NHBC technical standards, with a labelled arrow showing the BCO checks against the middle layer and a sub-arrow showing they drill down to the top layer when a Part is contested
16
The Standard Building Control Follows
The Building Regulations 2010 plus the Approved Documents are the standard your building control officer enforces. Here's the full map for an extension.
Free with email
Planning appeal timeline showing key stages from refusal through appeal submission, council response, inspector site visit, and decision
17
Appealing a Planning Decision
How to appeal a refused householder planning application. Covers the 12-week deadline, written representations procedure, what the inspector looks for, realistic success rates, and when resubmitting makes more sense.
Free with email

What the planning phase decides

Planning is where a kitchen extension stops being an idea and becomes a fixed set of dimensions that other people have agreed to. Nothing gets dug. What gets settled is the legal permission to build, the drawings every trade will later price from, the structural numbers the build has to satisfy, and the budget you can honestly commit.

Four questions get answered here, and they are not interchangeable.

How big can it be, and under which route? Your house sits on one of three paths: build inside the national permitted development rules with no application at all, use the prior approval route for a larger single-storey rear extension if the depth overruns those limits, or make a full householder planning application. Establish the route before you spend on anything else, because it sets the depth, height, roof form and materials you are designing to.

Who draws it? Someone has to produce existing and proposed drawings that a council will accept and a builder can price. That might be an architect, an architectural technologist or a designer working to the same standard. The choice affects cost and how much hand-holding you get through the application. Finding an architect covers how to judge one.

Will it stand up? Removing a rear wall to open the kitchen into the extension means a beam, and a beam means calculations. A structural engineer produces the numbers that size the steel, the padstones and the foundations under them.

Can you pay for it, and when? The phase ends with a budget that includes a contingency and a payment plan matched to the build programme rather than to hope. Budgeting and contingency sets out how to build that number without kidding yourself.

The order these tasks run in

The route decision comes first because it is the cheapest thing to change and the most expensive to get wrong. Design to permitted development limits and you may never file an application. Design a shape that needs consent and you have committed yourself to the council's timetable.

Design follows the route. Drawings produced before anyone has checked the limits get redrawn.

The structural engineer runs alongside the design rather than after it. Beam positions change internal layouts, and the calculations have to exist before building control assesses the structure, so bringing the engineer in early stops the design being reopened later.

Only then does the application go in. Submitting a planning application walks through the documents, the site and location plans, and the validation checks councils apply before the clock even starts. How long the decision then takes depends a lot on where you live: our council planning league table shows how quickly your council decides householder applications, and links to its planning search.

Two things run in parallel with all of this and have their own clocks. Building control notification is a separate approval from planning, and it applies even where no planning application is needed. And if you will excavate near a neighbour's foundations or build off a shared wall, the statutory notice periods under party wall agreements have to run their course before anyone starts. Both are started during planning, not when the groundworker is already booked.

What getting this phase wrong costs you later

Errors here are the only ones in the whole build that can stop work entirely rather than just slow it down.

Guess the route wrong and you either lose months resubmitting or finish an extension that has no lawful permission behind it. A conveyancer will find that. It becomes a price reduction, an indemnity policy or a stalled sale, years after the plasterer has left.

Skip the engineer until the application is drafted and you submit incomplete, get invalidated, and rejoin the queue.

Serve party wall notice late and the build stalls on day one with trades booked and a skip on the drive.

Set a budget without contingency and the first thing that changes on site, and something always changes on site, is funded by cutting something else. Usually insulation or glazing, the two items you will live with longest.

None of this is bad luck. It is a phase that was rushed because nothing visible happens in it.

Start here

Work out which route your house is on. Everything else in this phase depends on that answer, and it costs nothing but the reading. Begin with do you need planning permission, then work down the tasks above in order.