Tower Hamlets Extension Guide 2026: Planning Permission, Costs & Conservation Areas
Tower Hamlets has some of the most varied planning conditions in east London — from free-and-clear Victorian terraces in Bow to tightly controlled Georgian streets in Spitalfields. Here is what you need to know before extending.
Quick Answer
Tower Hamlets has active conservation area controls and Article 4 directions across much of the borough. Permitted development applies in non-designated areas. Costs run 10–15% above the London average due to access constraints. Planning takes 8–13 weeks for standard applications.
£60k–£90k
Rear extension (3m×5m)
8–13 weeks
Planning time
14+
Conservation areas
Check your specific property constraints
Free Property CheckTower Hamlets: The Borough and Its Housing
Tower Hamlets is one of the most densely populated boroughs in England. It stretches from Spitalfields and Whitechapel in the west through Stepney, Mile End, Bow, and Poplar, to the Isle of Dogs and Canary Wharf in the south. That geographical range means the housing stock — and therefore the planning context for extensions — varies enormously.
The Victorian terraced housing concentrated in Bow, Mile End, Stepney Green, and Bethnal Green forms the bulk of the borough's residential stock. These are the properties most commonly extended — single-storey rear extensions, side returns, and loft conversions. Georgian terraces in Spitalfields and parts of Bethnal Green sit within some of the most closely controlled conservation areas in London. Post-war housing estates occupy large parts of Poplar, Limehouse, and Shadwell — these are typically leasehold flats where extensions are not possible and the planning rules for householder works are less relevant.
The density of the borough matters for extensions in practical terms. Access to rear gardens is frequently via an archway through the terrace or a narrow side passage, which increases scaffold and materials costs. Shared rear courts — common in denser Stepney and Whitechapel streets — mean more party wall notices and more neighbour engagement at the planning stage.
Housing stock by area
Tower Hamlets Local Plan 2031
Tower Hamlets submitted its new Local Plan to the Planning Inspectorate for independent examination in February 2026. The plan covers the period to 2031 and will, once adopted, replace the current Tower Hamlets Local Plan (2031) adopted in 2020. Until adoption, the existing adopted plan remains the primary policy document.
The key policies for householder extensions under the current adopted plan are:
Policy D.DH4 — Design Quality
Extensions must preserve or enhance the character of the existing building and the surrounding area. This applies regardless of whether planning permission is required. In practice, the council uses this policy to assess material choices, massing, and relationship to neighbouring properties.
Policy D.DH5 — Heritage Assets
Extensions affecting listed buildings, conservation areas, or their settings must demonstrate that the proposal preserves or enhances the significance of the heritage asset. Heritage statements are required for all conservation area applications. This policy underpins the council's detailed design guidance for sensitive areas.
Policy D.DH6 — Residential Amenity
Extensions must not cause an unacceptable loss of light, privacy, or outlook to neighbouring properties. The council applies the BRE 45-degree rule and daylight/sunlight guidance when assessing applications next to existing windows. Given the density of the borough, this is frequently a determining factor in decisions.
The emerging Local Plan 2031 continues these policies and places additional emphasis on sustainable design, biodiversity net gain, and sustainable drainage systems. Applicants in the borough should be aware that conditions requiring green roofs, permeable surfaces, and drainage attenuation are increasingly common on planning permissions.
Conservation Areas in Tower Hamlets
Tower Hamlets has over 14 designated conservation areas. These cover a significant proportion of the older residential housing in the borough. If your property is within a conservation area boundary, permitted development rights for most external works — including extensions, roof alterations, and cladding — are removed automatically by law, without the need for an Article 4 direction.
| Conservation Area | Main Streets / Character | Design Scrutiny |
|---|---|---|
| Spitalfields | Folgate Street, Elder Street, Fournier Street | Very high — many listed buildings |
| Victoria Park | Gore Road, Approach Road, Bonner Road | High — Victorian villas |
| Bethnal Green | Teesdale Street, Cyprus Street area | Moderate–high |
| Bow | Tredegar Square, Fairfield Road | Moderate–high |
| Limehouse Basin | Canal-side terraces, Commercial Road | Moderate |
| Stepney Green | Stepney Green, White Horse Lane | Moderate |
| Isle of Dogs | Narrow Street, Coldharbour | Moderate |
What conservation area designation means for extensions
- No permitted development for single-storey rear extensions, side extensions, or roof alterations — full planning permission is required for all of these
- Materials must match the original building — stock brick, lime pointing, and timber windows rather than render, uPVC, or Crittall. The council will specify this by condition
- Extensions must not project above or forward of the original building line at the front
- A heritage statement is required with any planning application in a conservation area, explaining how the proposal preserves or enhances the area's character
- For listed buildings, listed building consent is required in addition to planning permission. Unauthorised works to a listed building are a criminal offence
Spitalfields note: Spitalfields is exceptional even by conservation area standards. Many properties on streets like Folgate Street, Elder Street, and Fournier Street are Grade I or Grade II* listed. The council's conservation team expects the highest standard of heritage evidence and design quality. Pre-application advice is not optional here — it is essential.
Check your Tower Hamlets planning constraints
Enter your address to see conservation area designation, Article 4 directions, and listed building status for your property.
Article 4 Directions in Tower Hamlets
Article 4 directions allow councils to remove permitted development rights in specific areas beyond those already removed by conservation area status. Tower Hamlets has Article 4 directions in place across several parts of the borough, notably covering:
Victoria Park area
Article 4 directions covering the Victorian villa streets around Victoria Park remove PD rights for extensions, alterations to windows and doors, and cladding. Any external alteration requires a planning application.
Bow conservation area and surrounds
The Bow Conservation Area covers Tredegar Square and the formal Victorian streets north of the square. Article 4 applies to the conservation area boundary and some streets immediately adjacent.
Spitalfields and Whitechapel
Article 4 directions across the Spitalfields Conservation Area reinforce what conservation area law already requires. The key practical effect is that even works which might be permitted development in principle (such as very minor outbuildings) need a formal application.
How to check
Tower Hamlets publishes its Article 4 direction maps on the planning portal. The most reliable check is to use the council's online constraints map or our tool below, which pulls live planning data for your address.
Permitted Development in Tower Hamlets
Permitted development rights apply to the portions of the borough that are not within conservation areas and not subject to Article 4 directions. This covers a significant area, particularly in Bow, Mile End, Stepney, and the residential streets of Poplar outside the conservation area.
The national permitted development limits apply without modification in these areas:
- Terraced and semi-detached: up to 3m depth from original rear wall
- Detached houses: up to 4m depth
- Maximum height 4m (or 3m eaves if within 2m of boundary)
- Materials must be similar in appearance to the existing house
- Terraced and semi-detached: 3–6m depth (Neighbour Consultation Scheme)
- Detached: 4–8m depth
- Submit to Tower Hamlets planning (£120 fee). 42-day decision window.
Single-storey side extensions can be permitted development in non-conservation streets if they do not exceed half the width of the original house. Check carefully — many Tower Hamlets terraces sit on narrow plots where a side extension would either be physically impossible or require planning permission due to width limits.
Hip-to-gable loft conversions and rear dormers can qualify as permitted development in non-conservation streets. Dormer volume must not exceed 40m³ (terraced) or 50m³ (semi/detached). No changes to the front roof slope facing a highway.
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When a full planning application is required — whether because you are in a conservation area, exceeding PD limits, or building a two-storey extension — Tower Hamlets processes householder applications through its Development Management team.
Decision timescales
Tower Hamlets has a target of deciding 80% of householder applications within 8 weeks. In practice, straightforward applications in non-conservation areas are typically decided within 8–10 weeks from validation. Applications in conservation areas take longer — 10–13 weeks is typical — due to the additional consultation with the council's conservation officer.
Validation can add 2–4 weeks if documents are missing on first submission. Tower Hamlets' validation checklist requires accurate plans, a design and access statement, and a heritage statement for any application in a conservation area. Submitting incomplete applications is the most common cause of delay.
Application fees (2026)
Neighbour consultation
Tower Hamlets notifies adjacent neighbours by letter when a householder planning application is received. The standard consultation period is 21 days. In conservation areas, local amenity societies (including the Spitalfields Trust and the Victorian Society for Victoria Park area applications) are also consulted and frequently submit detailed responses. It is worth being aware that objections from these bodies carry significant weight with officers.
Design Requirements
Tower Hamlets planning officers apply the same design policies across the borough, but the practical requirements differ significantly between conservation and non-conservation areas.
In conservation areas
Materials
London stock brick is the default requirement for extensions to Victorian and Georgian properties in Tower Hamlets conservation areas. The council will specify the exact brick type and bond pattern by condition if necessary. Render is generally refused on brick-fronted terraces. Crittall-style steel windows are acceptable in some contexts; uPVC is not. Timber frames are appropriate where original windows were timber.
Height and building line
Rear extensions must not project above the existing eaves line of the main house. The extension ridge should be clearly subordinate to the main roof. Extensions must not project beyond the established rear building line of the terrace — that is, they should not protrude further into the garden than adjacent extensions already approved on the street.
Glazing
Large glazed rear elevations (bi-fold doors, roof lanterns, and skylights) are generally acceptable on rear extensions in conservation areas provided they are not visible from public space. The key test is whether the extension affects the character or appearance of the conservation area as seen from streets and public viewpoints.
Outside conservation areas
Design scrutiny is lower for extensions in Bow, Mile End, and other non-conservation streets. The main tests are the relationship to neighbouring amenity (light, privacy, outlook) and the visual relationship with the host building. There is more flexibility on materials — grey render, zinc cladding, and glazed structures are all approved in appropriate contexts. The council's design guidelines still require extensions to be "sympathetic" to the host building, but this is interpreted more loosely than in conservation areas.
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Extension Costs in Tower Hamlets 2026
Tower Hamlets extension costs run 10–15% above the inner London average. The main reasons are access — rear gardens often accessed only through the house or a shared archway — and the density of the borough, which increases scaffold hire, materials delivery, and waste removal costs. All figures below include VAT at 20%.
| Extension type | Typical size | Cost inc VAT | Notes |
|---|---|---|---|
| Rear extension | 3m × 5m (15m²) | £60k–£90k | All-in including architect, SE, building regs |
| Side return extension | 2m × 6m (12m²) | £50k–£80k | Higher per m² due to access and narrow working space |
| Loft conversion | Dormer or mansard | £60k–£95k | Mansard required in some conservation area streets |
| Wrap-around (rear + side) | Combined 20–28m² | £90k–£140k | Single project cost efficiencies apply |
Conservation area premium
Extensions in conservation areas — particularly in Spitalfields and Victoria Park — add significant cost beyond the base build. The main contributors:
Access constraints add-on costs
Specific to Tower Hamlets' dense urban environment:
Common Extension Types by Area
Victorian terraces in Bow and Mile End
The Victorian terraces on streets like Roman Road, Tredegar Road, and Rhondda Grove in Bow, and the streets around Mile End Park, are the most active area for extensions in Tower Hamlets. Most of these properties sit on plots with a clear rear garden and access via a side passage or rear gate. Rear single-storey extensions and loft conversions are both viable.
For properties outside the Bow Conservation Area, permitted development applies for rear extensions up to 3m depth and — under prior approval — up to 6m. A dormer loft conversion to the rear is usually achievable as permitted development. The result is a 3-bedroom terrace that can be extended to effectively 4 bedrooms with a proper family kitchen-diner without requiring a planning application.
Georgian properties in Spitalfields
Extending a Georgian property in the Spitalfields Conservation Area is a different project entirely. Most properties here are listed — many at Grade II*, which places them in the top 6% of listed buildings. Even minor internal works require listed building consent. External extensions are almost always refused unless they are genuinely reversible and subordinate.
Where extensions are possible, they are typically to the rear at low level (single-storey glazed extensions reading as clearly modern additions). The council and Historic England both expect a design approach that is legibly contemporary rather than pastiche, but using traditional materials. These projects require specialist architects with conservation experience and typically cost £120k–£200k+ for even modest schemes due to the level of documentation and specification required.
Victorian terraces in Bethnal Green
Bethnal Green sits between the strict control of Spitalfields and the relative freedom of Bow. The conservation area covers parts of the area, but a large proportion of the Victorian terrace streets are outside it. Side return extensions are popular here — many Bethnal Green terraces have a narrow side return that can be infilled to create a full-width kitchen-diner. Costs for side returns run £50k–£80k all-in.
Planning Tips for Tower Hamlets
Use pre-application advice
Tower Hamlets offers a pre-application advice service for householder applications. The fee is £75–£250 depending on the complexity of the scheme. For conservation area applications and any project where you are uncertain about the council's likely position, pre-application advice pays for itself. It reduces the risk of a refused application (and the wasted architect fees that come with it) and often results in faster decision-making when you do submit.
Commission a heritage statement early
For any application in a Tower Hamlets conservation area, a heritage statement is a validation requirement — not an optional extra. Commission this from your architect or a specialist heritage consultant before you finalise the design. A good heritage statement shapes the design rather than justifying it after the fact, and significantly improves the chances of a positive officer recommendation.
Design Review Panel for larger schemes
Tower Hamlets refers significant or sensitive applications to its Design Review Panel. For householder applications this is rare, but for larger two-storey extensions or schemes in sensitive conservation areas (particularly Spitalfields), a voluntary design review before submitting can be useful. The Design Review Panel's support is noted by officers and can tip a borderline application towards approval.
Establish the original rear wall position
In Tower Hamlets, many Victorian terraces have an existing outrigger or Victorian WC extension at the rear. Permitted development depth is measured from the original rear wall of the house, not from the end of any existing extension. Your architect should establish the original building footprint before finalising the scheme — planning officers will check this.
Check for Thames Water public sewers
Tower Hamlets has an old and dense sewer network. Public sewers running through rear gardens are common, particularly on older Victorian streets. Building within 3m of a public sewer requires a build-over agreement with Thames Water, which adds cost and time. Check the Thames Water sewer map before finalising your extension footprint.
Frequently Asked Questions
Do I need planning permission for an extension in Tower Hamlets?
It depends on your location. In non-conservation streets (much of Bow, Mile End, Stepney outside designated areas), single-storey rear extensions up to 3m depth can qualify for permitted development. In the 14+ conservation areas (Spitalfields, Victoria Park, Bethnal Green, Bow, Limehouse Basin, and others), permitted development rights are removed — all extensions require full planning permission. Check your address first.
How long does planning permission take in Tower Hamlets?
Standard householder applications: 8–10 weeks from validation. Conservation area applications: 10–13 weeks, due to consultation with the conservation officer and amenity societies. Allow an additional 2–4 weeks if your application is not fully validated on first submission. Pre-application advice (£75–£250) can speed up decision-making by resolving officer concerns before you submit.
How much does an extension cost in Tower Hamlets in 2026?
All costs include VAT: rear extension 3m×5m (15m²) £60k–£90k all-in; side return (2m×6m, 12m²) £50k–£80k; loft conversion £60k–£95k. Tower Hamlets runs 10–15% above the London average due to access constraints (dense streets, limited vehicle access to rear gardens) and materials handling costs. Conservation area work adds heritage statement fees and material premiums on top.
What are the conservation areas in Tower Hamlets?
Tower Hamlets has over 14 conservation areas including: Spitalfields (very strict — many listed buildings), Victoria Park (Victorian villas, high design scrutiny), Bethnal Green, Bow (Tredegar Square area), Limehouse Basin, Stepney Green, Isle of Dogs (Narrow Street / Coldharbour area), and others covering parts of Whitechapel and Shadwell. In all of these, permitted development rights for extensions are removed.
Can I extend my Victorian terrace in Bow under permitted development?
If your property is outside the Bow Conservation Area (which covers Tredegar Square and surrounding formal streets), permitted development applies. You can build a single-storey rear extension up to 3m depth without any application, or up to 6m depth under the Neighbour Consultation Scheme (prior approval). A rear dormer loft conversion is also usually achievable as PD. Check the conservation area boundary first — some Bow streets are inside it.
What is required for an extension in the Spitalfields Conservation Area?
Spitalfields is one of the most controlled conservation areas in London. Permitted development is removed. Full planning permission is required, plus listed building consent if the property is listed (most are). A heritage statement is mandatory. Materials must match the original building (London stock brick, lime mortar, timber windows). The council and Historic England both consult on listed building applications. Expect 13–16 week decision times and heritage specialist fees of £2,000–£5,000.
Does Tower Hamlets offer pre-application planning advice?
Yes. Tower Hamlets operates a pre-application advice service for householder applications, typically costing £75–£250 depending on complexity. For conservation area applications or any project where there is uncertainty about the council's likely position, pre-application advice is strongly recommended. It reduces the risk of refusal and can speed up formal decision-making.
Summary
Tower Hamlets is a borough of contrasts. The Victorian terraces in Bow and Mile End offer straightforward permitted development opportunities for rear extensions and loft conversions. The Georgian streets of Spitalfields and the Victorian villas around Victoria Park sit within some of the most controlled conservation areas in London, where every extension requires planning permission, a heritage statement, and careful material specification.
The first question to answer for any Tower Hamlets extension project is whether your property is in a conservation area. If it is, the planning route, the design requirements, and the budget are all significantly different from a non-designated property a few streets away. Check your address before commissioning drawings.
For non-conservation area properties, Tower Hamlets is a practical borough to extend in. PD applies, decision times are reasonable, and the costs — while above the outer London average — reflect the access constraints of a dense inner-east London location rather than exceptional planning difficulty.
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