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One of the most common questions homeowners ask when approaching an architect is: how much will this cost? Architect fees in the UK are not fixed by law or by any professional body — each practice sets its own rates. However, there are well-established patterns in how architects structure their fees and what percentage of construction costs you can expect to pay at different project stages and scales.

How Do Architects Charge?

UK architects typically charge using one of four fee structures:

1. Percentage of Construction Cost

The most common fee structure for residential projects. The architect charges a percentage of the total construction cost (excluding VAT and architect fees). Typical percentages for residential work in 2025:

Project Type / Scale	Typical Fee Range (% of construction cost)
Small extension (under £80,000 construction)	12 – 18%
House extension (£80,000 – £250,000 construction)	10 – 15%
New build house or loft conversion (£200,000 – £500,000)	8 – 12%
Larger residential (£500,000+)	6 – 10%

Percentages appear counterintuitively higher for smaller projects because the architect’s fixed costs — client meetings, site visits, consultant coordination — do not reduce proportionally on a small job.

2. Fixed Fee (Lump Sum)

A fixed fee agreed for the entire project or for defined stages. This gives the client cost certainty. Many practices offer fixed fees for householder projects because these are well-understood scope items. Fixed fees are particularly common for planning-only services.

3. Time Charge (Hourly or Daily Rate)

Charged at an agreed hourly or daily rate. Common for feasibility studies, planning consultancy, or projects with ill-defined scope. Senior architects in London typically charge £100–£200 per hour; directors and sole practitioners £150–£300 per hour.

4. Stage Fee (Milestone Billing)

Fees split by RIBA Work Stage, billed as each stage is completed. Typical stage splits for a full service (Stages 0–6) on a residential project:

• Stage 0–1 (Strategic Definition, Preparation): 5–10%
• Stage 2 (Concept Design): 15–20%
• Stage 3 (Spatial Coordination and Planning): 20–25%
• Stage 4 (Technical Design): 25–30%
• Stage 5 (Manufacturing and Construction): 15–20%
• Stage 6 (Handover): 5%

Architect Fees for Common Residential Projects

Project	Construction Cost Estimate	Architect Fee Estimate
Single-storey rear extension (London)	£80,000 – £130,000	£10,000 – £18,000
Loft conversion (London)	£60,000 – £90,000	£8,000 – £14,000
Kitchen extension + refurb (London)	£100,000 – £200,000	£12,000 – £24,000
New build house (London, 150m²)	£400,000 – £700,000	£35,000 – £80,000
Planning-only service (extension)	N/A	£3,000 – £8,000 fixed fee

What Is Not Included in Architect Fees?

Standard architect fees typically do not include:

• Structural engineer fees (typically £1,500–£5,000 for residential projects)
• Planning application fee (£258 for householder in England)
• Building control fees (£500–£2,000 depending on project size)
• Party wall surveyor fees (£1,500–£4,000 per neighbour)
• Specialist surveys (drainage, asbestos, ecology)
• Interior design, furniture specification, or landscaping unless agreed

How to Compare Architect Quotes

When comparing quotes from different architects, check:

1. What RIBA stages are included? A quote that only covers to planning permission (Stage 3) will be lower than a full service to completion (Stage 6).
2. How is construction cost defined? Is it based on your budget estimate or their estimate of actual cost?
3. What triggers additional fees? If design changes are requested, will these be charged extra?
4. Who will work on your project? Is it the senior architect you met, or will it be delegated to junior staff?
5. What is included in contract administration? How many site visits per month? Are snagging visits included?

Frequently Asked Questions

Are architect fees VAT-able?

Yes — architectural services are subject to VAT at the standard rate (20%). Quotes should state whether fees are quoted inclusive or exclusive of VAT. Most professional service quotes are exclusive of VAT.

Can I get an architect for just the planning drawings?

Yes — many architects offer a planning-only or partial service. This is often the right approach for straightforward extensions where you plan to manage the build yourself or use a design-and-build contractor for technical drawings. Expect to pay £3,000–£8,000 for planning drawings and application management on a typical householder extension.

Is an architect the same as an architectural designer or technologist?

No. In the UK, the title “architect” is legally protected — you must be registered with the ARB to use it. Architectural designers and architectural technologists are not legally required to be ARB-registered and may charge lower fees. For complex or high-value projects, an ARB-registered architect’s professional indemnity insurance and qualifications provide important protection.

When should I start talking to an architect?

As early as possible. Even at the initial stage of considering a home improvement, an architect can advise on feasibility, planning constraints, and likely costs — saving you from investing in a scheme that will not get permission or that will exceed your budget. Most architects offer a free or low-cost initial consultation.

Crown Architecture is an ARB-registered architectural practice based in London. We offer transparent, fixed-fee quotes for residential extensions, loft conversions, and new builds across the capital. Contact us on 07443804841 or at 71-75 Shelton Street, London WC2H 9JQ.

Pre-application advice — sometimes called pre-app advice — is a service offered by most local planning authorities in England that allows homeowners, developers, and architects to discuss a proposed development with a planning officer before submitting a formal planning application. Using it effectively can be the difference between getting planning permission first time and receiving a refusal that costs months and thousands of pounds.

What Is Pre-Application Advice?

Pre-application advice is an informal consultation with a planning officer about a proposed development. The officer reviews your scheme and provides written feedback on:

• Whether the proposal is likely to be acceptable in principle
• What policies are relevant — local plan policies and national planning policy
• What the key issues or concerns are
• What additional studies or information might be required with a formal application
• Whether any design changes could improve the likelihood of approval

Pre-application advice is not a guarantee of permission. The officer’s view is informal and not binding on the local planning authority at the application stage. However, it gives invaluable insight into how the authority is likely to approach your application.

When Is Pre-Application Advice Most Valuable?

Pre-application advice is most valuable when:

• Your proposal is in a Conservation Area or near a listed building
• The scheme is larger or more complex than typical householder projects
• You are proposing something that may be contrary to policy (e.g., a new dwelling in the Green Belt)
• The site has planning history — previous refusals, existing conditions, or enforcement notices
• You want to understand what level of information (assessments, reports) will be required
• You want to build a relationship with the case officer before submitting

For straightforward Permitted Development works within known limits, you generally do not need to consult a planning officer before applying for a Lawful Development Certificate.

How Much Does Pre-Application Advice Cost?

Fees vary significantly between local planning authorities. There is no nationally fixed fee. Typical costs in 2025:

Application Type	Typical Pre-App Fee Range
Householder (extension, loft conversion)	Free – £300
Minor residential (1–4 dwellings)	£300 – £900
Small commercial or change of use	£400 – £1,200
Major residential (5+ dwellings)	£1,000 – £5,000+

Some authorities offer free pre-application advice for householder projects; others charge for even a brief written response. Check the local authority website before requesting advice.

How to Get the Most From Pre-Application Advice

Prepare Thoroughly Before the Meeting

Submit clear plans (even indicative ones), photographs of the site and surroundings, and a written description of what you are proposing and why. The more information you provide, the more specific and useful the feedback will be.

Ask Specific Questions

Rather than a general question about whether the scheme will get permission, ask specific questions: Is the proposed height acceptable in this streetscape? What level of justification will be needed for the departure from policy? Would you expect a heritage impact assessment to be required?

Bring Your Architect

Your architect can ask technical planning questions, translate the officer’s concerns into design changes, and demonstrate that the application will be properly prepared. Planning officers respond better to professionally prepared pre-app submissions than hand-drawn sketches.

Follow Up in Writing

If pre-application advice is given verbally in a meeting, follow up with a written summary and ask the officer to confirm. This creates a record you can refer to when preparing the formal application.

Pre-Application Advice and Heritage Assets

For projects affecting listed buildings or in Conservation Areas, pre-application engagement is particularly valuable. Historic England operates its own pre-application service for developments that might affect nationally significant heritage assets. Many local authorities also have specialist heritage officers who should be consulted at pre-application stage for such projects.

Does Pre-Application Advice Guarantee Approval?

No. Pre-application advice represents an officer’s informal view at a point in time. The formal planning application goes through a statutory process including public consultation and councillor decision-making. Policy context can change; new objections can emerge. However, a scheme well-tested at pre-application stage is substantially more likely to succeed than one submitted without prior engagement.

Frequently Asked Questions

Is pre-application advice confidential?

Generally yes at the time of submission, but information submitted at pre-application stage may be disclosed following a Freedom of Information or Environmental Information Regulations request after the pre-app process is complete.

Can I appeal if the pre-application advice is negative?

No — pre-application advice is not a formal decision and cannot be appealed. However, a negative pre-app response does not prevent you from submitting a formal application. You can take the officer’s concerns on board, redesign, and resubmit a pre-app, or proceed directly to a formal application with a response to the issues raised.

How long does pre-application advice take?

Written pre-application responses typically take 4–8 weeks from submission, though timescales vary considerably between authorities. Some offer a faster turnaround for a higher fee. Pre-application meetings with an officer can often be arranged within 2–4 weeks.

How do I request pre-application advice?

Most local planning authorities have a pre-application advice request form on their website. Submit your request form, site plans, and description of the proposed works, along with the fee payment. Some authorities accept requests by email; others require online submission through their planning portal.

Crown Architecture provides pre-application planning advice and full planning services for residential and commercial projects across London. Call us on 07443804841 or email info@crownarchitecture.co.uk.

Green roofs — also called living roofs or sedum roofs — are layers of vegetation planted on a waterproofed roof substrate. Once considered a specialist or architectural statement, they are increasingly required by local planning authorities across the UK as a condition of planning permission, particularly on flat-roofed extensions and new-build developments. This guide explains what green roofs are, when they are required, and what you need to know to include one on your project.

What Is a Green Roof?

Green roofs broadly divide into two types:

• Extensive green roofs: A thin substrate layer (60–200mm), planted with low-maintenance species such as sedum, moss, and grass. These are lightweight (70–170 kg/m² when saturated) and require minimal maintenance. They are the most common type on residential extensions and flat-roofed additions.
• Intensive green roofs (roof gardens): Deeper substrate (150mm+), capable of supporting shrubs, perennials, and even trees. These require more structural capacity, regular maintenance, and irrigation. They are more common on commercial developments and high-end residential projects.

When Are Green Roofs Required by Planning?

Green roofs are not universally required by planning policy, but they are increasingly specified in:

• Flat-roofed extensions in Conservation Areas: Many local authorities require green or living roofs on flat-roofed rear extensions as a condition of planning permission, to manage visual impact from upper-floor neighbours and to provide biodiversity benefits.
• Biodiversity Net Gain (BNG): Since February 2024, Biodiversity Net Gain under the Environment Act 2021 is mandatory for most planning permissions in England. Green roofs can contribute BNG units, making them an effective tool for meeting BNG requirements on constrained urban sites.
• London Plan Policy G5 (Urban Greening): The London Plan requires all major development to include urban greening as part of new or improved green infrastructure. Green roofs are one of the most common ways to meet this requirement.
• Local authority sustainability policies: Many councils — particularly in London — have supplementary planning documents requiring green roofs on flat-roofed buildings above a certain floor area.

Benefits of Green Roofs Relevant to Planning

When justifying a green roof in a planning statement or design and access statement, the following benefits are relevant to planning policy:

• Biodiversity: Supports pollinators, invertebrates, and nesting birds — directly contributing to biodiversity net gain
• Sustainable drainage: Retains 50–80% of rainwater in summer, reducing stormwater runoff and pressure on drainage systems
• Urban heat island effect: Reduces surface temperatures through evapotranspiration, addressing policy requirements for climate change adaptation
• Visual amenity: Improves appearance of flat roofs when viewed from above, addressing overlooking concerns from neighbouring upper floors
• Thermal performance: Adds insulation value and reduces cooling loads in summer

Do Green Roofs Need Planning Permission?

A green roof added to an existing flat roof is generally considered a change to the external appearance of the building. Whether it requires planning permission depends on the extent of the works:

• Adding a green roof to an existing flat roof (no structural changes): Generally falls within Permitted Development for dwellinghouses, provided the overall height does not increase beyond PD limits.
• Adding a green roof as part of a flat-roofed extension: Assessed as part of the extension application.
• Listed buildings: Any changes to a listed building require Listed Building Consent.
• Conservation Areas: Works to the roof of a dwelling in a Conservation Area may require permission depending on whether they materially affect the appearance of the building.

Structural Considerations for Green Roofs

Before specifying a green roof, a structural engineer must confirm that the roof structure can bear the additional load. An extensive sedum roof system weighing 120 kg/m² on a 20m² extension roof adds 2,400 kg of loading — equivalent to roughly 30 people standing on the roof. For existing roofs, this often requires structural assessment and potentially reinforcement of the rafters or roof deck.

Green Roof Costs in the UK

System Type	Cost per m² (installed)
Extensive (sedum matting)	£80 – £150/m²
Extensive (plug planted)	£100 – £180/m²
Semi-intensive	£150 – £250/m²
Intensive (roof garden)	£250 – £600+/m²

Frequently Asked Questions

Can a green roof be used on a pitched roof?

Yes, but it is more complex. Extensive systems can be installed on pitches up to about 30 degrees with appropriate retention systems. Steeper pitches require specialist anchoring and may not be suitable for green roof installation without significant additional cost.

How long does a green roof last?

A well-designed and installed green roof, with a quality waterproofing membrane, can last 40–50 years — longer than an unprotected flat roof, as the vegetation and substrate protect the membrane from UV degradation and temperature extremes.

Does a green roof need to be maintained?

Extensive sedum roofs are low-maintenance — typically requiring one or two visits per year to remove weeds, check drainage outlets, and replace failed plants. Intensive roof gardens require regular irrigation, fertilising, and pruning like any garden.

Is a green roof better than solar panels for planning purposes?

They serve different purposes. Solar panels generate energy; green roofs provide biodiversity and drainage benefits. For planning, a green roof is more likely to be required as a condition in Conservation Areas and for BNG compliance. Solar panels and green roofs can coexist on the same roof using raised panel systems.

Crown Architecture designs flat-roofed extensions with green roofs across London, advising on planning requirements, structural specifications, and biodiversity net gain compliance. Contact us on 07443804841 at 71-75 Shelton Street, London WC2H 9JQ.

Change of use planning permission is required when you want to use a building for a purpose different from its currently authorised use class. In England, land and buildings are classified into use classes under the Town and Country Planning (Use Classes) Order 1987 (as amended). Moving from one use class to another may require planning permission, or may be permitted under Permitted Development rights. This guide explains the current use class system, what changes require permission, and when you can proceed without a planning application.

The Use Class System in England (2025)

Following the September 2020 amendments, the main use classes are:

Use Class	Description	Examples
Class E (Commercial, Business and Service)	Broad commercial class	Shops, offices, cafes, gyms, nurseries, light industrial
Class F.1 (Learning and Non-Residential Institutions)	Education and community	Schools, libraries, public halls
Class F.2 (Local Community)	Small-scale community use	Small shops, swimming pools, outdoor sport
Class C1 (Hotels)	Short-term accommodation	Hotels, motels, boarding houses
Class C2 (Residential Institutions)	Residential institutions	Care homes, hospitals, boarding schools
Class C3 (Dwellinghouses)	Standard residential	Houses, flats, maisonettes
Class C4 (HMOs)	Small HMOs	3–6 unrelated occupiers sharing facilities
Class B2 (General Industrial)	General industrial	Factories, manufacturing
Class B8 (Storage and Distribution)	Storage and warehousing	Warehouses, distribution centres

Changes of Use That Do Not Require Planning Permission

The Town and Country Planning (General Permitted Development) (England) Order 2015 grants Permitted Development rights for certain changes of use:

• Class E to C3: Commercial buildings can be converted to residential under Class MA PD rights, subject to prior approval conditions including a 3-month vacancy test, flood risk, noise, natural light, and transport considerations.
• Within Class E: All uses within Class E can change freely without planning permission — from a shop to an office to a gym to a cafe, all within Class E.
• C4 to C3 and back: A property can move between C3 and C4 (small HMO) without planning permission under PD rights in most areas, unless an Article 4 Direction has removed these rights.
• Agricultural to residential: Class Q PD rights allow conversion of agricultural buildings to dwellings, subject to prior approval.

Changes of Use That Require Full Planning Permission

The following changes of use typically require a full planning application:

• C3 (dwelling) to C2 (residential institution) or C1 (hotel or B&B)
• C3 to sui generis uses (e.g., a house converted to a large HMO with 7+ occupiers)
• B2 (general industrial) or B8 (storage) to residential — no PD right exists
• Any change of use in areas where Article 4 Directions have withdrawn PD rights
• Changes requiring operational development beyond what PD rights allow

Article 4 Directions

Local planning authorities can make Article 4 Directions to remove specific PD rights in their area. Many London boroughs have Article 4 Directions removing the C3 to C4 (HMO) permitted change, meaning conversion to an HMO requires full planning permission. Always check with the local planning authority before relying on PD rights for a change of use.

How to Apply for Change of Use Planning Permission

1. Confirm the existing use class: Check the lawful use — apply for a Lawful Development Certificate if uncertain.
2. Identify the proposed use class: Is planning permission required? Does a PD prior approval route apply?
3. Prepare supporting documents: Planning statement, design and access statement, heritage statement, transport assessment, noise assessment, or flood risk assessment as required.
4. Submit via the Planning Portal: Application fees vary by use and floor area.
5. Respond to consultation: Statutory 8-week determination period applies (or 13 weeks for major applications).

Lawful Development Certificates for Change of Use

If you have been using a property for a particular purpose for more than 10 years (or 4 years for change of use to a dwelling), you may apply for a Lawful Development Certificate to confirm that the change of use has become lawful through time. An LDC costs £258 in England and provides legal certainty when selling or refinancing.

Frequently Asked Questions

Can I convert a commercial building to residential without planning permission?

In many cases, yes — Class E buildings can be converted to residential under Class MA PD rights, subject to prior approval. The building must have been vacant for at least 3 consecutive months, and prior approval is needed from the local planning authority covering flood risk, noise, natural light, and transport.

Do I need planning permission to run a business from home?

Usually no, provided the residential use remains the primary use and the business does not cause a material change in the character of the dwelling. If the business use becomes the primary use, planning permission may be required.

What is a sui generis use?

Uses that fall outside all use classes are sui generis — in a class of their own. These include theatres, nightclubs, casinos, petrol filling stations, and large HMOs with 7 or more occupiers. Any change to or from a sui generis use requires planning permission.

What is the difference between planning permission and change of use?

Change of use is a specific type of planning permission. You apply for planning permission, but the development being proposed is a material change in the use of land or buildings, rather than physical building works. Both require a planning application unless permitted development rights apply.

Crown Architecture provides planning consultancy and architectural services for change of use projects across London and the South East. Contact us on 07443804841 or at 71-75 Shelton Street, London WC2H 9JQ.

A basement conversion is one of the most ambitious and expensive home improvements available to UK homeowners. Whether you are lowering an existing cellar, underpinning to create headroom, or digging a new subterranean level, it can dramatically increase a home’s value in land-constrained London and the South East, where going down is often more cost-effective than moving or building upward.

Average Basement Conversion Costs in the UK

Basement conversion costs depend heavily on whether you are converting an existing usable cellar, lowering a cellar with limited headroom, or digging a completely new basement from scratch. These are three very different projects with very different budgets.

Project Type	Typical UK Cost	London Premium
Convert existing usable cellar (2m+ head height)	£20,000 – £40,000	£30,000 – £60,000
Lower existing cellar (underpinning + excavation)	£50,000 – £80,000	£75,000 – £120,000
New-build basement (full dig, tanking, structure)	£80,000 – £150,000+	£120,000 – £250,000+

Prices vary significantly based on ground conditions, access, proximity to boundaries and neighbouring foundations, and the specification of the finished space.

What Affects the Cost of a Basement Conversion?

1. Ground Conditions

London clay shrinks in dry conditions and expands when wet. A structural engineer must assess ground conditions before any scheme is designed. If your site is near trees, groundwater, or existing deep foundations, costs rise substantially.

2. Access for Excavation

If machinery cannot access your rear garden, all excavated material must be removed by hand. A standard rear excavation in London may require 80–150 tonnes of spoil to be removed at £60–£100 per tonne.

3. Party Wall Obligations

Basement excavations near the boundary will almost always engage the Party Wall etc. Act 1996. A party wall surveyor must be appointed for each affected neighbour. Costs typically range from £1,500–£4,000 per neighbour, and a neighbour has the right to appoint their own surveyor at your expense.

4. Tanking and Waterproofing

A dry basement requires either internal tanking, external tanking, or a cavity drain membrane channelling water to a sump pump. Structural waterproofing must comply with BS 8102:2009. Costs for tanking and drainage typically add £15,000–£40,000 depending on the system and basement size.

5. Structural Approach

Underpinning (the traditional sequential bay method) is typically the cheapest structural approach for lowering an existing floor. However, some sites require contiguous piled walls, secant piling, or a reinforced concrete box, which can double the structural cost.

Does a Basement Conversion Need Planning Permission?

Whether you need planning permission depends on the nature and scale of the works:

• Converting an existing cellar to habitable space: Usually falls within Permitted Development Rights — no planning permission required, but Building Regulations approval is mandatory.
• Creating a new basement under the house: Permitted Development in most cases, provided you are not significantly extending the footprint beyond the house and garden boundary rules.
• Adding a light well and external access: More likely to require planning permission, as you are creating a new opening in the public realm or significantly altering the house appearance.
• Conservation Areas and Listed Buildings: Full planning permission (and Listed Building Consent where relevant) is required.

Some London boroughs — notably Kensington and Chelsea, Westminster, and Camden — have specific supplementary planning guidance restricting iceberg developments. Always check with the local planning authority before proceeding.

Building Regulations for Basement Conversions

Basement conversions require Building Regulations approval regardless of whether planning permission is needed. Key regulations cover:

• Structural stability: Temporary and permanent works design; underpinning and excavation methodology
• Waterproofing: BS 8102:2009 compliance — Grade 3 (habitable space) typically required
• Ventilation: Adequate fresh air supply, particularly important in below-ground spaces
• Fire safety: Fire-resisting construction at the basement ceiling; adequate means of escape from basement rooms
• Sound insulation: Resistance to airborne and impact sound where adjacent to other dwellings
• Thermal performance: Insulation to meet Part L requirements

Is a Basement Conversion Worth the Investment?

In London and the Home Counties, a quality basement conversion typically adds 10–15% to a property’s value. A basement that creates an additional bedroom with en suite in Islington or Hampstead could add £200,000–£400,000 in value from a project costing £150,000–£200,000. Outside London, the economics are less compelling where property values are lower and construction costs are similar.

Frequently Asked Questions

How long does a basement conversion take?

A standard basement conversion in London typically takes 4–8 months from structural works commencing to practical completion. New-build basements with complex engineering can take 10–14 months. Party wall agreements and planning permissions add pre-construction time.

Do I need a structural engineer for a basement?

Yes, always. A structural engineer is essential for assessing ground conditions, designing temporary works, specifying the permanent structure, and signing off Building Regulations. For basements near boundaries, a specialist geotechnical engineer may also be required.

Can I convert a basement in a terraced house?

Yes — many of London’s most successful basement projects are in Victorian terraces. The structural and party wall challenges are significant but manageable with the right team. A structural engineer must design the underpinning sequence to protect adjacent foundations.

Do basements need special insurance?

Yes. Standard home insurance typically does not cover major structural works. You need specialist contractor insurance and should ensure your architect and engineer have adequate professional indemnity cover.

Crown Architecture advises homeowners on basement conversion feasibility, planning strategy, and architectural design across London. Contact us on 07443804841 or info@crownarchitecture.co.uk at 71-75 Shelton Street, London WC2H 9JQ.

Fences, walls, and gates around the curtilage of a residential property are among the most misunderstood planning topics in the UK. Many homeowners are surprised to discover that some boundary structures require planning permission, and that apparently straightforward works can trigger enforcement issues. Crown Architecture & Structural Engineering Ltd advises on boundary structure planning requirements for residential and commercial clients. This guide explains the rules for England in 2025.

Permitted Development for Fences, Walls and Gates

Under Class A of Part 2, Schedule 2 of the GPDO, the erection, construction, or alteration of gates, fences, walls or other means of enclosure are permitted development subject to conditions:

• Adjacent to a highway used by vehicular traffic: Maximum height of 1 metre. This applies to boundaries with roads, driveways accessing the highway, and footways.
• In any other location: Maximum height of 2 metres.

These limits apply to the height of the structure. A fence on a retaining wall is measured from the highest adjacent ground level.

When Planning Permission Is Required for Boundary Structures

Planning permission is required for:

• Fences, walls, or gates exceeding 1m adjacent to a vehicular highway
• Fences, walls, or gates exceeding 2m in other locations
• Any boundary structure on or adjacent to a listed building or within its curtilage (listed building consent may also be required)
• Boundary structures in conservation areas — restrictions on the height of fencing or walls facing a highway or footway may be imposed by Article 4 Directions or local policies; check with the LPA
• Where PD rights have been removed by a condition on the original planning permission for the house (many new-build estates have conditions removing fencing PD rights to preserve an open-plan character)

Conservation Areas

In conservation areas, PD rights for boundary structures are restricted. Specifically:

• No PD right applies to the erection of a gate, fence, wall or other means of enclosure that would be within the curtilage of a dwelling and adjacent to a highway (including a footway), where the structure would be higher than the structure it replaces or higher than the adjoining existing boundary.
• Check the specific conservation area Article 4 Directions for your area — some conservation areas have more restrictive requirements on boundary treatments.

Boundary Disputes and Ownership

Planning permission deals with the planning position. Separate from planning are boundary ownership and the civil law rights to erect structures. Before building a fence or wall on or near a boundary:

• Confirm the position of the boundary (from the title plan and Land Registry)
• Check the deeds for any boundary maintenance obligations (“T marks” on the title plan indicate which party maintains which boundary)
• Confirm whether any covenant in the deeds restricts fencing type or height

A planning permission does not override a private covenant. Erecting a fence in violation of a covenant can result in a civil claim from the beneficiary of the covenant.

Structural Considerations

Higher or heavier boundary walls require structural engineering input:

• Masonry walls over approximately 1.8m typically require engineering calculations for stability and foundation design
• Walls on steep slopes or retaining walls (holding back soil on one side) require engineering design regardless of height — see our Retaining Walls guide
• Gates hung on posts require engineering assessment of the post foundation to carry swinging and impact loads
• Walls near trees require assessment of root influence on foundation depth

Party Wall Act and Boundary Walls

A wall built on or adjoining a shared boundary may engage the Party Wall etc. Act 1996. Where you intend to build a wall astride the boundary (with the wall straddling both properties), this is a party wall and requires a party wall notice to the adjoining owner. Building within 3–6m of the neighbour’s foundations (for certain excavation depths) also engages the Act. (See our Party Wall Act guide.)

How Crown Can Help

Crown Architecture & Structural Engineering Ltd provides planning advice and structural engineering for boundary walls — from planning application preparation to structural design and Building Regulations submissions for larger wall structures. Call us on 07443804841 to discuss boundary structures for your project.

Frequently Asked Questions

Can my neighbour object to my fence?

If your fence is within permitted development limits, your neighbour’s objection has no bearing on your planning position — you are entitled to build without permission. However, the neighbour may have private law rights (deeds, covenants, property boundaries) that restrict your right to build. And if you are building on the boundary, Party Wall Act obligations apply. Consulting a solicitor is advisable where there is a neighbour dispute about boundary works.

Do I need building regulations for a garden wall?

Most garden walls (under 1.8m) do not require Building Regulations approval. Taller walls and structural retaining walls may require Building Regulations under Part A (Structure) — consult building control for walls above approximately 2m height.

Can I build a 2m fence anywhere in my garden?

Within the garden boundary that is not adjacent to a vehicular highway, a 2m fence is PD in most cases. Check whether your property has PD rights removed by conditions (common on new-build estates), whether you are in a conservation area (where additional restrictions may apply), and whether the boundary is with a listed building.

Building Regulations Part S (Infrastructure for the Charging of Electric Vehicles) came into force in England in June 2022. It requires new residential and non-residential buildings, and certain buildings undergoing major renovation, to provide electric vehicle (EV) charging infrastructure. With EV adoption accelerating rapidly and the government’s target to end sales of new petrol and diesel cars by 2035, Part S is an increasingly important consideration in new build and extension design. Crown Architecture & Structural Engineering Ltd coordinates Part S compliance as a standard element of every relevant project. This guide explains what Part S requires and how to comply.

What is Building Regulations Part S?

Part S was introduced by the Electric Vehicles (Smart Charge Points) Regulations 2021 and the Building Regulations etc. (Amendment) (England) 2021. It sets out requirements for:

• EV charge points in new residential buildings with associated parking
• Cable routes for EV charge points in new residential buildings without associated parking
• EV charge points in new non-residential buildings with more than 10 parking spaces
• EV charge points in existing non-residential buildings undergoing renovation where more than 10 parking spaces are attached

Requirements for New Dwellinghouses

For a new dwelling with an associated parking space (including houses with garages or parking pads):

• At least one EV charge point per dwelling must be provided at the associated parking space
• The charge point must be at least a 7kW single-phase smart charge point with appropriate sockets (Type 2 socket, BS EN 62196-2) and safety features
• The charge point must be a “smart” charge point capable of communication with the grid (OCPP or similar protocol)

Requirements for New Residential Buildings (Flats)

For new purpose-built blocks of flats with associated parking:

• One active EV charge point for every 5 dwellings (with an associated parking space)
• Cable routes (passive infrastructure — ducting without charge points) for all remaining dwellings with associated parking spaces

For example, a 20-unit block with 20 parking spaces must provide 4 active charge points and passive cable routes to 16 further spaces. This allows future charge point installation without expensive retrospective electrical work.

Requirements for Non-Residential Buildings

For new non-residential buildings with more than 10 parking spaces:

• One EV charge point for every 5 parking spaces (minimum)
• Cable routes for at least 1 in 5 of all remaining spaces

For existing non-residential buildings undergoing major renovation where the building has more than 10 parking spaces:

• As above — at least one charge point per 5 spaces and cable routes to the remainder

Exemptions

Part S does not apply where:

• The cost of the electrical infrastructure for EV charging would exceed 7% of the total construction cost of the building (the “cost cap” exemption)
• The building is a listed building
• The building is in a conservation area (partial exemption may apply)
• The building is a heritage monument

Technical Requirements for EV Charge Points

Part S charge points must:

• Provide a minimum output of 7kW (single phase) or 22kW (three phase)
• Include a Type 2 socket (Mode 3 charging)
• Be “smart” capable (schedulable, with metering and communication capability)
• Be OZEV-approved (Office for Zero Emission Vehicles approval list)
• Include an appropriate residual current device (RCD) for safety
• Be weatherproof and vandal-resistant where in external locations

Part P electrical safety requirements apply to all EV charge point installations — they must be installed by a Part P competent person and notified to building control.

Structural and Electrical Implications

Providing EV charging infrastructure has implications beyond simply mounting a charge point on a wall:

• Electrical supply capacity: Installing multiple 7kW charge points in a car park significantly increases the peak electrical demand on the building’s supply. Load management (smart charging schedules) can mitigate this but the incoming DNO supply must be adequate. For new buildings, the incoming supply should be specified from the outset to accommodate the Part S requirement.
• Cable routing: Conduit and cable routes from the electrical distribution board to each parking space must be designed and installed. Where spaces are distant from the distribution board, this can involve significant cable runs and associated cost.
• Structural penetrations: Cable routes through structural walls and floors must be fire-stopped and coordinated with structural elements. The structural engineer should be consulted where cable routes pass through structural beams or slabs.
• External works: Charging posts in car parks require ground fixings. In new car parks, charge point post foundations can be incorporated into the slab design; in retrofit situations, core drilling through existing concrete may be needed.

How Crown Can Help

Crown Architecture & Structural Engineering Ltd coordinates Part S compliance for new residential and commercial developments — incorporating EV charge points and cable routes into the design from the outset, coordinating with building services engineers on electrical supply capacity, and ensuring structural provisions for cable penetrations and post foundations are included in the design. Call us on 07443804841 to discuss Part S for your project.

Frequently Asked Questions

Does Part S apply to extensions to existing houses?

Part S applies primarily to new buildings. However, where a new or enlarged parking space is being created as part of a new build or extension, the requirements should be assessed. Material changes of use (converting commercial to residential) may also trigger Part S requirements. For straightforward house extensions that do not create new parking, Part S is unlikely to apply.

What is a “smart” charge point?

A smart charge point is one that can communicate with the electricity network and user to schedule charging at optimal times (e.g. overnight at lower tariffs). Smart charge points typically use the OCPP (Open Charge Point Protocol) standard and must be able to delay, pause, or adjust the charge schedule in response to grid signals. OZEV publishes an approved list of compliant smart charge points.

Does Part S apply to permitted development extensions?

Part S applies to new buildings and major renovations. Permitted development extensions that do not involve a new dwelling or a material change to parking provision are unlikely to trigger Part S. However, where an extension creates a new garage or parking space as part of the development, the LPA building control team should be consulted on whether Part S applies.

What is the government grant for EV charging?

The OZEV (Office for Zero Emission Vehicles) EV Chargepoint Grant provides funding toward the cost of installing smart EV charge points for residential buildings, including flats and rental properties. The grant amount and eligibility varies — check the current OZEV scheme for residential and landlord grants. The grant scheme is separate from Part S compliance obligations.

Churches, chapels, temples, mosques, and other places of worship are among the most complex and rewarding buildings to work on. Many are listed, have unusual historical construction methods, and present structural challenges not encountered in modern buildings. Structural engineering for heritage buildings requires sensitivity to historic fabric, understanding of traditional materials and construction, and careful selection of repair and alteration approaches that are minimally intrusive. Crown Architecture & Structural Engineering Ltd works on heritage and ecclesiastical buildings across the UK. This guide explains the structural and planning considerations for these projects.

What Makes Heritage Building Structural Engineering Different?

Unknown Materials and Construction

Historic buildings were built without modern standards and documentation. Material strengths, foundation depths, and structural details are often unknown. The structural engineer must investigate the existing construction before designing any alteration — through visual inspection, testing (material sampling, rebound hammer testing of masonry, ground investigation), and sometimes invasive opening-up works.

Historic Structural Systems

Many historic structures use systems that are no longer built — timber king post trusses, stone masonry arches and vaults, cast iron columns, wrought iron beams, early reinforced concrete, and traditional lime mortar construction. Understanding how these systems work structurally and how they have responded to centuries of load and movement requires specialist knowledge.

Reversibility

Conservation principles emphasise reversibility — interventions should be capable of being undone without damage to the historic fabric. This often rules out the most structurally efficient solution (e.g. epoxy repair of timber versus traditional scarfing) in favour of approaches that preserve options for future maintenance and repair.

Minimum Intervention

The philosophy of minimum necessary intervention minimises the amount of historic fabric disturbed or replaced. Where possible, the structural engineer strengthens rather than replaces, repairs rather than rebuilds, and supplements rather than substitutes.

Common Structural Issues in Heritage Buildings

Roof Structure Decay

Timber roof structures in old buildings are frequently affected by dry rot, wet rot, and death watch beetle. Decay typically concentrates where timbers are embedded in masonry (wall plates, purlin ends, rafter feet) where moisture accumulates. Assessment involves probing, moisture measurement, and identification of the fungal or insect species responsible. Treatment involves removing the source of moisture, treating active infestations, and repairing or replacing structurally compromised timbers.

Foundation Settlement

Many historic buildings have shallow foundations by modern standards. Settlement cracks — typically diagonal from corners of windows and doors — are common and require careful assessment to distinguish between stable historic movement (which has stopped) and active movement (requiring investigation). Monitoring over 6–12 months establishes whether movement is active before intervention.

Arch and Vault Distress

Masonry arches and vaults transmit loads through compression. Distress in arches (cracking at the crown, spreading at the springing points) indicates that the thrust from the arch is not being adequately contained by the surrounding structure. Structural analysis must determine whether the arch is in a safe condition or requires propping, tie-rod installation, or reconstruction.

Tower and Steeple Stability

Church towers and steeples are tall, slender structures subject to wind and bell-ringing dynamic loads. Cracking at the base of towers, out-of-plumb conditions, and deterioration of mortar joints are common issues. Structural assessment includes measurement of out-of-plumb geometry, mortar sampling, and (for bellframes) dynamic analysis of bell-ringing loads.

Planning and Listed Building Consent for Church Alterations

Most churches and places of worship are listed buildings. Structural works require:

• Listed Building Consent (LBC) for any works affecting the special interest of the building
• Planning permission for external alterations visible from outside
• Faculty for works to Church of England (CoE) churches — the ecclesiastical faculty system operates instead of listed building consent for CoE churches, administered through the Diocesan Advisory Committee (DAC)

Non-CoE places of worship (Roman Catholic, Methodist, Baptist, Islamic, Jewish, etc.) are subject to the standard LBC and planning permission regime as for any listed building.

The Faculty System (Church of England)

Church of England churches are exempt from listed building consent under the Ecclesiastical Exemption. Instead, the faculty system administered by the diocese controls works. The Diocesan Advisory Committee (DAC) advises the Chancellor of the Diocese who grants or refuses the faculty. For major structural works, the DAC typically requires a structural engineer’s report and (for significant works) may refer to the Church Buildings Council or Historic England for advice.

Conversion of Redundant Churches

Many historic churches are being converted to residential, office, or community use as congregations decline. Conversion of a listed former church requires both planning permission for change of use and listed building consent for the alterations. Key structural challenges include:

• Installing new floor levels within a large open space
• Providing fire compartmentation without compromising the historic interior
• Adding insulation to meet Part L without damaging historic fabric
• Routing new services through or around historic structural elements
• Ensuring the external envelope remains watertight following installation of new internal structures

Structural Monitoring

Before designing an intervention, understanding the extent and rate of movement is essential. Structural monitoring typically involves:

• Tell-tales across cracks to measure opening/closing
• Datum pegs and level surveys to measure settlement
• Inclinometers to measure tilting of towers and buttresses
• Digital crack monitoring with automatic alerts for rapid movement

Monitoring over 6–12 months provides the evidence base for engineering intervention and is often required by LBC/faculty proceedings before consent for major structural works is granted.

How Crown Can Help

Crown Architecture & Structural Engineering Ltd provides structural engineering assessments and design for heritage buildings — including churches, chapels, and places of worship. We work sensitively with historic fabric, coordinate with conservation architects and heritage consultants, and prepare the structural documentation required for LBC and faculty applications. Call us on 07443804841 to discuss a heritage building structural project.

Frequently Asked Questions

Do I need a structural engineer to report to the DAC for a faculty application?

The DAC’s requirements depend on the nature and scale of the proposed works. For significant structural works (new floor, major roof repair, installation of new structural elements), a structural engineer’s report is almost always required. The DAC’s guidance documentation sets out what is typically needed for different categories of works.

Can I use modern materials in a listed historic building?

The use of modern materials in listed buildings is assessed case by case. For structural repairs, conservation philosophy generally favours like-for-like repair using traditional materials (lime mortar, traditional timber species, natural stone) where feasible. However, where traditional repairs are not adequate or available, modern materials may be accepted where they are compatible with the historic fabric, are reversible, and are specified with the conservation officer’s agreement.

What is the difference between dry rot and wet rot?

Dry rot (Serpula lacrymans) is a highly aggressive fungal decay that can spread through masonry and affect large areas of timber. It requires higher levels of moisture to establish but can spread to drier areas once established. Wet rot is caused by various species of fungus that require consistently damp conditions and do not spread into drier timbers. Dry rot treatment is more extensive and expensive than wet rot treatment and requires removal of affected timber beyond the visible decay.

Small-scale wind turbines can provide on-site renewable electricity generation for homes and businesses, reducing energy bills and carbon emissions. In many cases, small domestic wind turbines fall within permitted development rights — but the conditions are more restrictive than for solar panels, and wind turbines are rarely acceptable in urban areas. Crown Architecture & Structural Engineering Ltd advises on wind turbine planning requirements and structural implications. This guide explains the 2025 rules.

Permitted Development for Standalone Wind Turbines (Residential)

Under Class B of Part 14, Schedule 2 of the GPDO, a single freestanding wind turbine at a dwellinghouse is permitted development, subject to conditions:

• Only one turbine per property
• The hub height must not exceed 11.1m
• The blade must not exceed 3.1m radius
• The turbine must be positioned at least the distance of the hub height plus the blade radius from the nearest shared boundary
• The turbine must not be installed on a listed building or within its curtilage
• The turbine must not be installed within a World Heritage Site or Safety Hazard Area
• Only one previous wind turbine installation on the property (either attached or freestanding)
• The installation must comply with the MCS Planning Standards for noise and shadow flicker

Permitted Development for Roof-Mounted Wind Turbines

Roof-mounted wind turbines are technically more complex and noisier than freestanding turbines. Class A of Part 14 provides limited PD rights for roof-mounted turbines on dwellinghouses, with similar conditions to freestanding turbines. However, roof-mounted turbines are rarely suitable for urban terraced houses due to turbulence from surrounding structures significantly reducing energy output.

When Planning Permission Is Required

Full planning permission is required for wind turbines where:

• The turbine exceeds the PD size limits
• It is in a conservation area, AONB, National Park, or World Heritage Site
• The property is a listed building
• PD rights have been removed by an Article 4 Direction
• The turbine is commercial (for electricity export, not domestic use)
• Multiple turbines are proposed

Large commercial wind turbines (above approximately 50kW capacity) fall under planning legislation as EIA development and require Environmental Impact Assessment for sites in sensitive locations.

Noise and Shadow Flicker

Wind turbines generate noise from blade rotation and gear mechanisms, and shadow flicker when blades pass between the sun and neighbouring windows. The MCS Planning Standards require:

• Noise levels at neighbouring dwellings to be assessed against background noise levels, with turbine noise not exceeding 35 dB(A) or 5 dB above background (whichever is higher)
• Shadow flicker at any neighbouring dwelling not to exceed 30 hours per year or 30 minutes per day

Compliance with these standards is a condition of the PD right. Failure to comply may result in enforcement action.

Structural Implications

Wind turbine installations have structural implications that must be considered:

• Freestanding turbines: The mast must be designed for the turbine thrust loads, gravitational loads, and dynamic loads from blade rotation. Foundations must be adequate for the moment transferred from the mast to the ground. A structural engineer should design the mast and foundation for turbines above approximately 5m hub height.
• Roof-mounted turbines: Turbines impose dynamic loads (vibration, thrust) on the roof structure. The existing roof must be assessed for adequacy. Vibration from roof-mounted turbines can also be transmitted to the building interior, creating noise nuisance for occupants.

Commercial Wind Turbines

Commercial wind turbines (typically 100kW to multi-MW onshore turbines) require full planning permission. Planning assessments for commercial turbines address noise, shadow flicker, visual impact, ecology (particularly birds and bats), radar and telecommunications impacts, and cumulative impacts with other turbines. The planning policies for commercial onshore wind have been significantly liberalised in recent years as the UK pursues its clean energy targets, but opposition in rural areas remains strong.

How Crown Can Help

Crown Architecture & Structural Engineering Ltd provides structural engineering for wind turbine masts and foundations. Call us on 07443804841 to discuss structural requirements for a wind turbine installation.

Frequently Asked Questions

Are small wind turbines effective in urban areas?

Generally not — urban areas have turbulent, low-quality wind that significantly reduces turbine energy output. Wind speeds in urban areas are typically well below the minimum needed for economic electricity generation. Rural sites with consistent, open-aspect winds are far more suitable. Always commission an energy yield assessment before investing in a wind turbine installation.

How much electricity can a small domestic wind turbine generate?

A 6kW turbine (approximate maximum residential scale under PD) in a good wind location (average wind speed 6m/s or more) might generate 10,000–14,000 kWh per year — roughly 3–4 times a typical home’s electricity consumption. In practice, most urban and suburban sites have much lower wind speeds and corresponding lower generation. At current electricity prices (approximately 25p/kWh), a well-sited turbine could save £2,500–£3,500 per year.

Do wind turbines need planning permission in Scotland?

The permitted development rules for wind turbines in Scotland are different from England. In Scotland, the Householder Permitted Development Rights include provisions for small wind turbines but with different size limits and conditions. The planning system for commercial wind in Scotland is also different, with different height thresholds for EIA and national policy strongly supportive of onshore wind.

Adding additional storeys to existing buildings — known as “upward extensions” or “airspace development” — is now possible under permitted development rights in many cases. Class A of Part 20, Schedule 2 of the GPDO allows certain residential buildings to be extended upward without a full planning application, subject to a prior approval process. Crown Architecture & Structural Engineering Ltd provides structural engineering for upward extension projects. This guide explains how Class A works, what buildings are eligible, and what structural requirements apply.

What is Class A of Part 20?

Class A permits the extension of purpose-built blocks of flats, terraced houses, and semi-detached houses upward by one or two additional storeys, subject to prior approval from the LPA. The right was introduced in August 2020 as part of the government’s drive to increase housing supply through densification of existing residential buildings.

Buildings Eligible for Upward Extension

Class A applies to:

• Detached buildings in certain use classes (Class AA) — where the building is detached and in Use Class C3 (dwelling houses) or certain commercial uses — up to two additional storeys
• Terrace and semi-detached houses (Class A) — up to one additional storey on a one-storey house, or two additional storeys on a house already two storeys or more
• Purpose-built blocks of flats — up to two additional storeys on blocks of three or more storeys

Key Height and Size Limits

• The resulting building must not exceed 18m in height
• The new storeys must not exceed the height of the existing storey below
• The footprint of the new storeys must not exceed the footprint of the existing building
• Only one upward extension per building under this right

What Class A Does NOT Apply To

Class A does not apply to:

• Listed buildings or buildings within the curtilage of a listed building
• Buildings in AONBs, National Parks, World Heritage Sites, or Conservation Areas
• Buildings in areas at risk of flooding (Flood Zones 2 and 3) unless appropriate mitigation is demonstrated
• Buildings where PD rights have been removed by an Article 4 Direction
• Buildings constructed before 1 July 1948 or after 5 March 2018

Prior Approval: What the LPA Assesses

The prior approval for a Class A upward extension covers:

• Transport and highways impacts
• Impacts on amenity of adjoining premises (overlooking, loss of light, noise)
• Structural integrity of the host building
• Appearance of the additional storeys in relation to the existing building
• External appearance of the additional storeys

The LPA must consult the adjoining owner/occupier and the highway authority. The prior approval application requires drawings showing the proposed new storeys in context and a structural assessment confirming the existing building can carry the additional loading.

Structural Requirements for Upward Extensions

This is where structural engineering becomes critical. Adding one or two storeys to an existing building increases the loads on the entire structure below — walls, columns, floors, and foundations. Before any upward extension can proceed, the structural engineer must assess:

Foundations

The existing foundations were designed for the original building loads. Adding storeys increases those loads by 20–50% or more. A structural assessment must determine whether the existing foundations can carry the additional load without excessive settlement. If they cannot, options include:

• Enlarging the existing footings
• Installing additional piles or underpinning elements
• Reducing the structural weight of the new storeys (through lightweight steel or timber frame) to minimise the load increase

Existing Structural Frame

Existing masonry walls, columns, and beams must be checked for the increased loads. For older buildings, original structural details may not be available and the engineer must carry out site investigations (opening up, materials testing) to characterise the existing structure.

New Storey Structure

The new storeys themselves require full structural design — walls or columns, floors, roof structure, and connections to the existing building. Lightweight construction (cold-formed steel frame, timber frame, SIPS panels) is typically preferred to minimise the additional loading on the existing structure. Factory-made modules can further reduce on-site construction time and structural impact.

Wind Stability

Taller buildings experience higher wind loads. The existing structure must be checked for lateral stability under the increased wind loads on the additional storeys. For some buildings, additional bracing or shear walls may be required.

Building Regulations for Upward Extensions

Class A prior approval does not include Building Regulations approval. A full Building Regulations application must be submitted separately. Requirements include:

• Part A structural design for the new storeys and assessment of the existing structure
• Part B fire safety — means of escape from the new storeys, fire detection, compartmentation of new flats
• Part E sound insulation if new flats are created above existing
• Part L energy efficiency for new floor, roof, and wall elements
• Part M accessibility — lift provision required for buildings over two storeys

Costs for Upward Extensions UK 2025

• Prior approval application fee: £120 per new dwelling created (capped at £35,000)
• Structural assessment of existing building: £2,000–£8,000 depending on building size and complexity
• Structural design of new storeys: £3,000–£12,000
• Construction cost (one additional storey, residential): £80,000–£150,000 per new flat created, highly variable

How Crown Can Help

Crown Architecture & Structural Engineering Ltd provides structural assessments of existing buildings for upward extension viability, design of new storey structures, and coordination of the prior approval and Building Regulations processes. Call us on 07443804841 to discuss your upward extension project.

Frequently Asked Questions

Can I add a storey to my Victorian terraced house under Class A?

Victorian terraced houses are not eligible for Class A rights as they were constructed before 1 July 1948. Full planning permission is required to add a storey to a pre-war house. However, loft conversions with dormers may be possible under standard Part 1 permitted development rights.

Do I need a structural survey before applying for Class A prior approval?

Yes — the prior approval process requires evidence that the existing structure can carry the additional loading. The structural engineer’s assessment is a key supporting document for the prior approval application. Without this, the LPA is likely to refuse or condition the application.

Can upward extensions be used on commercial buildings?

Yes — Class A also applies to certain commercial buildings converted to residential use under Class MA (office-to-residential). After conversion, the resulting residential building may be eligible for upward extension under Class A, creating additional units above the conversion. This stacking of PD rights has been used by developers to maximise residential yield from commercial buildings.