Planning Permission or Building Regs: Which You Need

Planning permission and building regulations are separate systems asking different questions. A job can need one, both or neither. This guide sets out what common projects usually need in England, who signs them off and which certificate to keep for the day a buyer asks.

Planning permission decides whether you may build something at all. Building regulations decide whether it is built safely. They are run by different teams and applied for separately. One never implies the other, so a job can need both, either or neither.

Most of the confusion comes from both being loosely called "getting it signed off". Plenty of extensions have planning permission and no building regulations certificate, which is the worse of the two to be missing when you come to sell.

This guide covers England in detail, with the main differences for Wales, Scotland and Northern Ireland near the end. The tables give the usual answer for common projects. Your own home can be the exception, so treat them as the start of a conversation with your council rather than a ruling.

The short version

Planning permission decides whether you may build something, while building regulations decide whether it is built safely.
Permitted development is planning permission granted nationally within set limits; it does nothing about building regulations.
Flats and maisonettes have no householder permitted development rights, while listed buildings, conservation areas and Article 4 areas have fewer.
Building regulations work ends with a certificate, either a completion certificate from building control or a compliance certificate from the installer's competent person scheme.
The planning rules for heat pumps changed on 29 May 2025 and for solar panels on 27 August 2026, so older guidance on both is out of date.
In England a council has 10 years to act on planning breaches completed since 25 April 2024 and 10 years to require faulty building work to be put right.

Two systems, two questions

Planning permission is decided by your local planning authority. It is about the effect of a building on everybody else: its size, its position, how it looks, what it is used for and what it does to the neighbours' light and privacy. A planning officer is not checking whether your beam will hold the roof up.

Building regulations are enforced by building control, which is either the council's own team or a private registered building control approver. They cover whether the work is safe and sound: structure, fire safety, insulation, ventilation, drainage, glazing and electrics.

The two do not talk to each other. A rear extension usually needs building regulations approval and often needs no planning application. A new boiler needs building regulations and never planning permission. Changing what a building is used for can need planning permission even when no building work is done. Being told you did not need planning is not the same as being told you needed nothing.

Permitted development is permission you already have

Permitted development rights are a planning permission granted nationally, so long as the work stays inside set limits and conditions. You are not escaping the planning system; you are using a permission it has already given. They do nothing at all about building regulations.

For a house in England, the main limits for a single-storey rear extension are:

3 metres beyond the original rear wall for a terraced or semi-detached house and 4 metres for a detached one, with a maximum height of 4 metres
Up to 6 metres and 8 metres respectively under the larger home extension scheme, which needs a prior approval application so the council can hear from the neighbours first
Materials similar in appearance to the house, with nothing forward of the front (principal) elevation
No more than half the land around the original house covered by extensions and outbuildings together, where "original" means as first built, or as it stood on 1 July 1948 for an older house

Loft conversions have a volume allowance of 40 cubic metres for a terraced house and 50 cubic metres for other houses, with nothing higher than the existing roof and nothing on the roof slope at the front.

These limits change. Heat pumps changed on 29 May 2025 and solar panels on 27 August 2026, so GOV.UK's householder technical guidance (last updated in September 2019) predates both. The Planning Portal and your council carry the current rules. Our free home lookup shows what the national planning data records over an address in England, such as a conservation area or an Article 4 direction; the council's own records are the final word.

Your home may not follow the usual rules

Everything in the tables below assumes an ordinary house with its permitted development rights intact. Flats and maisonettes have no householder permitted development rights at all. Listed buildings need listed building consent for works affecting their character, inside or out. Conservation areas, National Parks, National Landscapes, the Broads and World Heritage Sites have many rights cut back. A council can withdraw rights across an area with an Article 4 direction. Many newer estates lost theirs through a condition on the original planning permission. None of this is visible from the pavement. Before you start, ask your council's planning team whether the work needs permission and its building control team what the regulations require. If you want the planning answer in writing, a Lawful Development Certificate for proposed work gives a legally binding decision for half the normal planning fee. Leaseholders may need the landlord's consent as well.

Common projects: extensions, conversions and outbuildings

In these tables "often" means many projects of that kind need it, "usually not" means most do not, "depends" means the answer turns on the details underneath and "yes" means expect it. They describe an ordinary house in England.

Project	Planning permission?	Building regulations?	Who certifies it	What to keep
Single-storey extension	Depends: often permitted development	Yes	Building control	Plans, completion certificate
Two-storey extension	Often	Yes	Building control	Decision notice, plans, completion certificate
Loft conversion	Depends: often permitted development	Yes	Building control	Plans, engineer's calculations, completion certificate
Garage conversion	Usually not	Usually yes	Building control	Completion certificate
Conservatory	Depends: treated as an extension	Usually not, if it meets the exemption	Building control, if not exempt	Glazing and electrical certificates
Garden office or outbuilding	Usually not, within limits	Depends on size, use and position	Building control, if needed	Plans, electrical certificate

Extensions. A rear extension of more than one storey can go 3 metres beyond the rear wall under permitted development and must be more than 7 metres from the boundary opposite. A side extension must be single storey, no more than 4 metres high and no wider than half the original house. Building regulations apply to every extension: structure, fire safety, insulation and drainage.
Lofts. The extension must be set back about 20 centimetres from the original eaves, with no balconies or raised platforms. Side windows must be obscure glazed and, if they open, more than 1.7 metres above the floor. Building regulations cover the structure, the stairs, fire safety and insulation. If you share a wall with a neighbour, the Party Wall etc. Act 1996 may also apply in England and Wales.
Garage conversions. There is usually no planning application where the work is internal and the building is not enlarged, though some estates have the rights removed by condition. Turning a garage into a room you live in normally needs building regulations approval.
Conservatories. For planning, a conservatory follows the same rules as any other extension. For building regulations it is normally exempt if it is at ground level, under 30 square metres and separated from the house by external-quality walls, doors or windows, with independent heating on separate controls and compliant glazing and electrics. A new structural opening into the house needs approval. Taking out the separating doors later can bring it back under the regulations.
Garden offices and outbuildings. Permitted development allows an outbuilding behind the front of the house for incidental use (not a self-contained home) with eaves no higher than 2.5 metres; a total height of 4 metres with a dual-pitched roof or 3 metres with any other; 2.5 metres overall within 2 metres of a boundary. Building regulations do not normally apply under 15 square metres with no sleeping accommodation. Between 15 and 30 square metres they do not apply if there is no sleeping accommodation and the building is at least 1 metre from any boundary or built substantially of non-combustible materials. A new electrical circuit to power it is notifiable either way.

Common projects: work inside the house

Project	Planning permission?	Building regulations?	Who certifies it	What to keep
Removing an internal wall	Usually not	Often; yes if load-bearing	Building control	Engineer's calculations, completion certificate
Chimney breast removal	Usually not	Yes	Building control	Engineer's drawings, completion certificate
Bathroom refit	Usually not	Depends on the work	Building control or the installer's scheme	Electrical certificate, any completion certificate
Bathroom where there was none	Usually not	Usually yes	Building control	Completion certificate
Electrical work	Usually not	Depends on the work	Registered electrician's scheme or building control	Electrical Installation Certificate, compliance certificate
New gas boiler	Usually not	Yes	Gas Safe Register, via the engineer	Gas Safe certificate, Benchmark checklist

Walls and chimney breasts. Building regulations normally apply to removing or opening up an internal wall. A load-bearing one needs approval and a structural engineer's calculations for whatever replaces it. Removing a chimney breast always needs building regulations approval, with an engineer's drawings and calculations, because whatever sits above has to be supported. A listed home needs listed building consent for internal changes too.
Bathrooms. Refitting with new units generally needs no approval, but new drainage or electrical work in the refit may. Putting a bathroom where there was none is likely to need approval for ventilation, drainage, structure, electrics and fire safety. Every new bathroom also needs extract ventilation.
Electrics. In England three kinds of work are notifiable: a new consumer unit (fuse box), a complete new circuit and alterations to existing circuits around a bath or shower. A registered electrician self-certifies the work and notifies it; anybody else has to tell building control before starting. Like-for-like replacement of a socket or a switch is not notifiable, though it is still a job for a qualified electrician.
Boilers. A Gas Safe registered engineer must notify the installation within 30 days. Gas Safe then posts a Building Regulations Compliance Certificate to the address, usually within 10 to 15 working days. Gas work is never a DIY job. What a boiler service includes covers looking after it afterwards.

Common projects: roofs, windows, energy and driveways

Project	Planning permission?	Building regulations?	Who certifies it	What to keep
Replacement windows and doors	Usually not, if similar in appearance	Yes	FENSA or CERTASS installer, or building control	FENSA or CERTASS certificate
New roof covering	Usually not, if it looks the same	Depends on how much is replaced	Building control or a registered roofer	Certificate, guarantee
Solar panels	Usually not, within limits	Usually yes	MCS installer and electrician's scheme	MCS and electrical certificates
Air source heat pump	Usually not, within limits	Yes	MCS installer	MCS certificate, commissioning records
EV charger	Usually not, within limits	Usually yes	Registered electrician's scheme	Electrical certificates
Driveway	Depends on the surface	Usually not	Council, for a dropped kerb	Kerb approval, invoice

Windows and doors. Building regulations have applied to all replacement glazing since 1 April 2002. An installer registered with FENSA or CERTASS certifies the work; otherwise it goes through building control. Repairs such as replacing broken glass are normally exempt. For planning, a bay window counts as an extension. New upper-floor side windows must be obscure glazed and either fixed shut or opening only more than 1.7 metres above the floor.
Roofs. Re-roofing that does not materially change how the house looks usually needs no planning permission. Rooflights must not stick out more than 150 millimetres from the roof slope. For building regulations, no application is normally needed if the work affects less than 25% of the whole building envelope and less than 50% of the roof. Beyond either, or if the structure changes, the fire performance changes significantly or the new covering is 15% or more heavier, you need approval. Renovating more than half of a roof can also mean bringing its insulation up to current standards where that is technically, functionally and economically feasible.
Solar panels. On a pitched roof, panels may stick out no more than 0.2 metres and must not rise above the highest part of the roof (chimneys aside). On a flat roof they may rise no more than 0.6 metres above its highest part. A new order in force from 27 August 2026 added limits for equipment on walls and balconies, 0.2 metres where it adjoins a highway and 0.4 metres elsewhere. Plug-in solar is not permitted development on wooden walls, balconies, enclosures or timber-clad sections. A listed home needs consent and conservation areas have extra limits. Building regulations normally apply because the roof has to carry the weight and the electrics are new.
Heat pumps. Since 29 May 2025 an air source heat pump at a house in England is permitted development if the unit is no bigger than 1.5 cubic metres, is the only one on a semi-detached or terraced house (two are allowed on a detached house), is not on a pitched roof and meets the MCS 020(a) noise standard. The old rule keeping units 1 metre from the boundary has gone. Listed buildings are excluded. In a conservation area a unit cannot go on a wall or roof that fronts a highway. Building regulations apply to every heat pump installation; an MCS certified installer is the usual route.
EV chargers. A wall-mounted charger is permitted development if it is no bigger than 0.2 cubic metres, sits in an area lawfully used for off-street parking and is outside the grounds of a listed building. A freestanding charging post can be up to 1.6 metres high at a house. The old restrictions on distance from a highway were removed on 29 May 2025. Fitting a charger usually means a new circuit, which is notifiable electrical work.
Driveways. A new or replacement driveway of any size needs no planning permission if it is permeable (gravel or permeable blocks) or drains onto a lawn or border. A traditional impermeable surface over 5 square metres with no drainage needs permission. This applies to houses, not flats or maisonettes. Driving across the pavement needs a dropped kerb, which the council approves separately.

Who signs it off and what you actually get

There are three routes to building regulations approval in England. Each leaves different paperwork behind, which matters when you go looking for it years later.

Your council's building control. You submit full plans (a decision within five weeks, or two months if you agree to it) or, for smaller jobs, a building notice, which lets you start two days later. An inspector visits at stages. The council issues a completion certificate within eight weeks of the work finishing, as long as it complies.
A registered building control approver. A private firm does the same job and tells the council through an initial notice. At the end it issues a final certificate; ask for it by name before you pay the last bill.
A competent person scheme. For windows, boilers, electrics, roofing, heat pumps and more, a registered installer certifies their own work, tells the council if needed and sends you a certificate within eight weeks. It also shows up in a buyer's solicitor's searches. It is very easy to bin as junk mail.

Two rules follow from that. Ask before the work starts who is notifying building control, because if the answer is a shrug, the answer is you. And treat the certificate as the proof, not the invoice: an invoice shows you paid somebody, not that the work met the standard.

How to prove work was done on your home goes through every certificate and how to replace a lost one. How to check a tradesperson covers checking an installer's registration before they start.

If the work is already done

Unapproved work is common and rarely a disaster, but the time limits are longer than a lot of older advice says.

Planning in England. A council can take enforcement action within 10 years of a breach substantially completed on or after 25 April 2024. For building work completed before that date the limit was 4 years, which is why so much informal advice still says four. Which rule applies to an older breach is a question for a solicitor rather than a guess.
Building regulations. A council can serve a notice requiring non-compliant work to be removed or altered up to 10 years after it was completed. That has applied in England since 1 October 2023 and in Wales since 1 July 2026.

There are ways to put it right:

Retrospective planning application. Asks for permission after the event.
Lawful Development Certificate for an existing use or development. Asks the council to confirm that something already built is lawful, for example because it was within permitted development or the time for enforcement has passed. It is optional and the answer is legally binding.
Regularisation certificate. Building control can certify unauthorised work carried out on or after 11 November 1985. Parts of the work may have to be opened up, tested or sampled. The certificate is evidence of compliance, though not conclusive evidence.

The real cost is delay, usually six weeks into a sale when the buyer's solicitor asks a question nobody can answer; the documents needed to sell a house include the consents for any work done. Where the worry is safety rather than paperwork, have the work looked at by a qualified professional whatever the paperwork says.

Wales, Scotland and Northern Ireland

Wales. The planning system is similar but the permitted development rules are Welsh, with their own guidance. The air source heat pump rules changed on 1 June 2026: the 3 metre boundary rule went, units can be up to 1.5 cubic metres, two are allowed on a detached house, air-to-air units are included and all must meet MCS 020(a). Building regulations are set by the Welsh Government. More electrical work is notifiable than in England: everything except replacing fittings, repairs and a few small additions.
Scotland. Most building work needs a building warrant from the council before it starts. When the work is finished you submit a completion certificate, which the council accepts or rejects within 14 days. New work cannot be occupied until it is accepted. Unauthorised work goes through a late completion certificate. Scotland has its own permitted development rules, so the English limits above do not carry over.
Northern Ireland. Planning and building control are both run by the 11 councils, building control under the Building Regulations (Northern Ireland) 2012. Permitted development is restricted for listed buildings, conservation areas and Areas of Outstanding Natural Beauty. Extensions to flats need permission. A Certificate of Lawful Use or Development gives a formal ruling, for a fee.

What to keep afterwards

The paperwork from a job is worth most the day it arrives and gets harder to replace every year. For each project, keep:

Planning. The decision notice, the approved drawings and any letters discharging conditions, or the Lawful Development Certificate.
Building regulations. The completion, final or competent person certificate, with the application or notification reference.
Design. The structural engineer's calculations and drawings, which the next person to touch that wall will want.
Neighbours. Any party wall notices, agreements or award.
The trade. The quote, contract and invoice; the firm's details and registration numbers; any guarantee with its insurance backing.
Photographs. Before, during and after, especially anything about to be covered up.

A buyer's solicitor will ask about alterations and consents, usually years after anybody remembers the details. If the work was done before you owned the house, building your home's service history covers getting the paperwork back.

homehogs keeps the planning reference, the building regulations number and the certificate against the job itself, so the extension and its paperwork stay together.

Sources

Last fact-checked 5 October 2026.

Keep the certificate with the job it belongs to

homehogs records each job with its planning reference, building regulations number and certificate, so the paperwork stays attached to the extension rather than loose in a drawer.

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Alex Wilson

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Common questions

What is the difference between planning permission and building regulations?

Planning permission decides whether you may build something at all, looking at its size, position, appearance, use and effect on the neighbours. It comes from your local planning authority. Building regulations decide whether the work is built safely, covering structure, fire safety, insulation, ventilation, drainage and electrics. Building control checks those. A job can need one, both or neither.

Does permitted development mean I do not need building regulations?

No. Permitted development is a planning permission granted nationally for work that stays within set limits, so it only removes the need to apply for planning permission. Building regulations still apply in full. A rear extension built under permitted development still needs building regulations approval and should end with a completion certificate.

Do I need planning permission for an air source heat pump?

Often not. Since 29 May 2025, one air source heat pump on a semi-detached or terraced house, or two on a detached house, is permitted development in England if each unit is no bigger than 1.5 cubic metres, is not on a pitched roof and meets the MCS 020(a) noise standard. The old rule keeping units 1 metre from the boundary no longer applies. Listed buildings and some positions in conservation areas still need permission. Building regulations apply to every installation.

Do I need planning permission for solar panels?

Usually not on a house in England, within limits. Panels must not stick out more than 0.2 metres from a pitched roof or rise more than 0.6 metres above a flat one. Since 27 August 2026 there are also limits for panels on walls and balconies and restrictions on plug-in solar. Listed homes need consent and conservation areas have extra restrictions. Building regulations normally apply because of the roof load and the electrics.

Do replacement windows need building regulations approval?

Yes. Building regulations have applied to all replacement glazing in England since 1 April 2002. An installer registered with a competent person scheme such as FENSA or CERTASS certifies the work and you receive a certificate; otherwise the work must go through building control. Planning permission is not usually needed for a house if the new windows look similar to the old ones, but flats, listed buildings and some conservation areas are different.

How long can a council take enforcement action over unapproved work?

In England the planning time limit is 10 years for breaches substantially completed on or after 25 April 2024. Before that date the limit for building work was 4 years. For building regulations, a council can require non-compliant work to be removed or altered for up to 10 years after completion, a rule in force in England since 1 October 2023 and in Wales since 1 July 2026. A solicitor can tell you which rules apply to older work.

What is a Lawful Development Certificate?

It is a legally binding decision from your council that a use or a piece of building work is lawful. A certificate for proposed work confirms in advance that it falls within permitted development, for half the normal planning fee. A certificate for existing work confirms that something already built is lawful. It is optional and does not replace planning permission where permission is needed.