Replacement Dwelling Cost in Richmond upon Thames

A replacement dwelling is the demolition of an existing house and the construction of a new house in its place. In planning terms it is treated as the erection of a new dwellinghouse — Use Class C3 — and that is the key fact that shapes both the process and the cost. It is not an extension, a conversion or a refurbishment; it is a new building, and the planning system, the Building Regulations, the Community Infrastructure Levy and the VAT rules all treat it accordingly. Understanding that from the outset avoids the single most common mistake, which is to budget and plan for a replacement dwelling as if it were a large extension.

People choose a replacement dwelling for good reasons. Sometimes the existing house is genuinely at the end of its life — poorly built post-war stock, a bungalow that wastes a generous plot, a house so badly configured or so structurally compromised that adapting it costs almost as much as replacing it and still leaves you with a compromise. Sometimes the existing home simply cannot deliver what a modern family needs — the layout, the light, the energy performance, the accessibility — and no amount of extension will fix the underlying problem. And sometimes a plot is worth far more with a well-designed new house on it than with the tired one it currently carries, which is why replacement dwellings are common in high-value areas like Richmond.

The decision between extending and replacing is partly financial and partly about what you can actually achieve. Extending is usually cheaper per square metre and can often use permitted development for part of the work, but you inherit the existing house's constraints — its structure, its floor levels, its orientation, its foundations. Replacing costs more and needs full planning permission, but gives you a coherent, modern, energy-efficient home designed from scratch to suit the plot and the way you live. On many Richmond plots, particularly where the existing house is small or poor relative to the land, replacement is the option that unlocks the site's real potential.

This page assumes you are seriously considering, or have decided on, a replacement dwelling in Richmond, and want to understand what it will cost and how the process works. We cover the planning route, the borough's policies on the size and design of replacement houses, the demolition and construction costs, the CIL calculation and the all-important existing-dwelling offset, the energy standards, the fees, and the reasons schemes are refused — everything you need to build a credible appraisal before you commit.

The first and most important planning fact about a replacement dwelling is that it almost always needs full planning permission. Demolishing a house and building a new one is the erection of a new dwellinghouse, and that is not something the permitted development rules allow you to do without a full application on the vast majority of plots. The permitted development rights that let you extend, add a loft dormer or build in the garden do not extend to knocking the whole house down and starting again. So a replacement dwelling in Richmond is a full planning application, assessed against the whole of the borough's Local Plan and the London Plan, not a lighter prior-approval or notification route.

This matters for cost because a full planning application is a fuller, more discretionary and more document-heavy process than permitted development. The council does not simply check a short list of matters; it weighs the whole proposal — its size, height, massing, footprint, design, impact on neighbours, impact on the character of the street and any conservation area, trees, drainage, biodiversity and more — against its adopted policies. That means a fuller set of drawings and supporting documents, a real risk of refusal if the design is wrong, and a timescale measured in months rather than weeks. It also means that the design and the planning strategy are where a replacement dwelling is really won or lost.

There is one important nuance worth knowing. Demolition of an unlisted dwellinghouse can in some circumstances be permitted development in its own right (subject to a prior-approval notification about the method and timing of demolition), but that only covers the act of demolition — it does not give you permission for the new house. And where the property is listed, or in a conservation area, even the demolition is controlled: you may need conservation area consent or listed building consent, and demolition of a building that contributes to a conservation area is often resisted. In Richmond, with its many conservation areas, the demolition side of a replacement dwelling is not automatically straightforward and has to be checked at feasibility.

The practical upshot is that a Richmond replacement dwelling should be approached as a proper full planning project from day one. That is not a reason to be daunted — hundreds of replacement dwellings are consented across London every year — but it is a reason to design it carefully, to understand the borough's policies before you draw a line, and to build the fees, reports and timescale of a full application into the budget from the start. The rest of this page explains exactly what that involves.

The London Borough of Richmond upon Thames adopted a new Local Plan and Policies Map on 7 October 2025, replacing the previous 2018 Local Plan. This is the policy framework against which a replacement dwelling is now assessed, and it is unusually design-conscious even by London standards, because Richmond is one of the most attractive and tightly protected boroughs in the capital. The plan divides the borough into nine 'places', each with its own character-based strategy, and its policies place strong weight on local character, design quality, the setting of the River Thames, protected views, trees and the amenity of neighbours.

For a replacement dwelling, the central policy questions are about the relationship between the new house and both the old one and its surroundings. The council will look closely at the proposed size, height, footprint, bulk and massing — not in the abstract, but relative to the existing house, to neighbouring properties and to the prevailing pattern of the street. A replacement that is dramatically larger, taller or bulkier than the house it replaces, or than its neighbours, is far harder to justify than one that respects the scale and rhythm of the area. This is not a fixed numerical cap in the way some boroughs apply to Green Belt replacements, but a design judgement about whether the new house sits comfortably in its context.

Amenity is the other decisive test. Richmond's Local Plan carries detailed policy on living conditions and the relationship between buildings — including the borough's long-standing approach to daylight, sunlight, outlook, privacy and 'sense of enclosure', and minimum distances between habitable-room windows. A replacement dwelling that is closer to a boundary, taller at the flank, or differently positioned than the house it replaces can create overlooking or overshadowing that the old house did not, and that is one of the most common reasons replacement schemes run into difficulty. Designing to protect neighbours' amenity from the first sketch is essential, not an afterthought.

Layered on top are Richmond's area-specific designations: dozens of conservation areas covering large parts of the borough, many listed and locally listed buildings, protected views (including those associated with Richmond Hill and the Thames), Thames Policy Area controls near the river, flood risk zones along the Thames and its tributaries, and strong tree protection. Any of these can apply to a given plot, and each shapes what a replacement dwelling can be and therefore what it costs to design and consent. Establishing exactly which designations affect your plot is the first thing we do, because they set the boundaries of the whole project.

The Community Infrastructure Levy is a charge that many local authorities, including Richmond, levy on new floorspace to help fund infrastructure. It is charged per square metre of new gross internal floorspace, and on a brand-new house on a bare plot it can be a significant sum. On a replacement dwelling, though, CIL behaves very differently — and understanding why is the single most valuable thing on this page, because it is the point most people get wrong and the point that most often decides whether the numbers work.

Richmond's borough CIL was adopted in 2014 and charges residential development at a base rate of £190 per square metre in the south and west of the borough (including Teddington and western Twickenham) and £250 per square metre in the north and east (including Barnes, eastern Twickenham and most of Richmond). Those base rates are index-linked and rise each year: for 2025, the indexed residential rates are approximately £310.84 and £409.00 per square metre respectively. On top of the borough charge sits the Mayor of London's CIL (MCIL2); Richmond falls in Band 1, with a 2025 indexed rate of around £94.79 per square metre. So the combined levy on genuinely new floorspace in Richmond is real money.

Here is the crucial part. CIL is charged on the net additional floorspace a development creates, not on the whole new building. Where an existing building on the site is to be demolished, and that building has been in lawful use for a continuous period of at least six months within the three years before permission is granted, its gross internal floorspace can be deducted from the floorspace of the new house before CIL is calculated. On a replacement dwelling, the house you are demolishing is almost always a lawfully occupied home, so its floorspace is offset — and you pay CIL only on the difference between the new house and the old one.

The effect is often dramatic. If you demolish a 150 square metre house and replace it with a 200 square metre one, you are charged CIL on roughly 50 square metres of net additional floorspace, not on the full 200 — a saving of three-quarters of the levy on a like-for-like replacement, and potentially all of it where the new house is the same size as or smaller than the old one. This 'existing floorspace deduction' is precisely why a replacement dwelling can be so much more CIL-efficient than building on an empty plot, and why the CIL figure that frightens people on first reading is usually far smaller in reality. Getting the calculation and the evidence right is one of the most financially important tasks in the whole project.

The existing-dwelling offset is generous, but it is not automatic — it turns on the demolished building having been in lawful use, and the burden of proving that lies squarely with the applicant. 'Lawful use' in CIL terms means the building was actually being used for its lawful purpose, not merely that it had a permitted use on paper. The leading case, R (Hourhope) v Shropshire Council, confirmed that a building must genuinely have been in use — a house that had been standing empty and unused for years might not qualify, even though it is lawfully a dwelling. The precise requirement is that the building was in lawful use for a continuous period of at least six months within the three years ending on the day planning permission first permits the chargeable development.

For a normal replacement dwelling this is rarely a problem: you are demolishing a house that someone has been living in, and council tax records, utility bills, tenancy agreements, electoral roll entries and similar evidence readily demonstrate the six months of lawful residential use. But there are traps. If the existing house has been empty for a long time — perhaps bought as a derelict wreck, or left vacant through a lengthy sale or probate — the six-months-in-three-years test can fail, and the offset can be lost. In that situation the floorspace of the old house may not be deductible, and you could be charged CIL on the full floorspace of the new one. That can turn a comfortable appraisal into a difficult one, so it must be checked early.

There is also a timing dimension worth understanding. The three-year window runs back from the grant of permission, so a long-empty house that you are planning to demolish should ideally have its offset position assessed before you buy, and certainly before permission is granted. Sometimes the answer is to demonstrate a qualifying period of use; sometimes, on a genuinely derelict property, the honest conclusion is that the deduction will not be available and the CIL should be budgeted at the full rate. Either way, it is far better to know at feasibility than to receive a CIL Liability Notice for a sum you had not planned for.

We handle the CIL side of a replacement dwelling as a core part of the service, not an afterthought. That means calculating the likely net-of-offset CIL at feasibility using the correct zone rate and the current indexation, assembling the evidence that the existing house was in lawful use, completing the CIL forms correctly (the additional information form, and the assumption-of-liability and commencement notices in the right order), and checking whether any relief or exemption applies — including the self-build exemption, which can remove the borough CIL entirely for someone building their own home to live in. Getting these forms and their timing right is essential, because a missed notice can forfeit a relief you were entitled to.

If you are building a replacement dwelling to live in yourself, rather than to sell on, you may qualify for the self-build CIL exemption, which can remove the borough CIL liability on the new home entirely. This is a national exemption available to anyone who builds, or commissions the building of, a new dwelling that they will occupy as their principal residence — and it applies to a self-commissioned replacement dwelling just as it does to a new house on a bare plot. For a homeowner replacing their own house in Richmond, it is one of the most valuable reliefs available.

The exemption is not automatic, and — like the existing-floorspace offset — it is unforgiving on process. You have to apply for and be granted the exemption before you start work, you must submit a commencement notice before development begins, and you must then occupy the home as your main residence and provide the required supporting evidence within a set period after completion (a completion certificate, proof of ownership and proof that it is your principal residence). If you sell or let the property, or fail to meet the conditions, within three years of completion, the exemption can be clawed back and the CIL becomes payable. Miss the commencement notice, and the exemption is lost — a common and painful mistake.

The self-build exemption and the existing-floorspace offset are separate mechanisms, and it is worth understanding how they interact. The offset reduces the net chargeable floorspace by deducting the demolished house; the self-build exemption removes the borough CIL liability on the qualifying self-build dwelling. For an owner-occupier replacing their own home, the practical result is often that borough CIL falls away almost entirely — but only if the paperwork and timing are handled correctly. This is precisely the kind of detail where good advice pays for itself many times over.

We advise on whether the self-build exemption applies to your project, prepare and submit the exemption claim and the commencement notice in the correct order and at the correct time, and make sure the post-completion evidence is ready. Where the exemption does not apply — for example on a replacement dwelling being built to sell — we make sure the existing-floorspace offset is claimed correctly instead, so you never pay more CIL than you have to. The theme throughout is the same: on CIL, the money is won or lost on getting the forms and the timing right.

Demolition is the first physical cost of a replacement dwelling, and while it is usually modest relative to the new build, it is not trivial and it carries its own risks. The cost of demolishing an ordinary two-storey house in London typically runs somewhere in the region of £10,000 to £30,000, depending on the size of the building, its construction, access to the site, and how the demolition is carried out. A large or awkwardly accessed house, or one attached to neighbours, sits toward the upper end; a modest detached bungalow on an open plot sits toward the lower end.

Several factors drive the demolition figure. Access is a big one: a house on a narrow lane or behind others, where machinery and skips are hard to bring in and rubble hard to take out, costs more than one with easy frontage. The construction of the existing house matters too — a simple brick-and-timber house is cheaper to take down than one with a lot of concrete or steel. And the presence of hazardous materials, above all asbestos, can add real cost: older houses frequently contain asbestos in soffits, textured coatings, cisterns, insulation or floor tiles, and licensed asbestos removal before demolition is a legal requirement that adds both cost and time.

Demolition also carries regulatory and party-wall obligations that a budget must reflect. You generally have to notify the local authority and the Health and Safety Executive of a demolition, and comply with the Construction (Design and Management) Regulations. Where the house adjoins or is close to a neighbour's property — common on many Richmond plots — the Party Wall etc. Act 1996 is very likely to apply to both the demolition and the new foundations, which means serving notices, and often appointing surveyors and agreeing a party wall award. These are process costs that are easy to overlook and expensive to ignore.

There is also the question of what to do with the ground once the old house is gone. Grubbing out the old foundations, dealing with old drainage runs, removing hardstanding, and disposing of the resulting material all add to the demolition and enabling-works cost, and can uncover surprises — old cellars, made ground, contamination, or foundations that are deeper or larger than expected. A sensible replacement-dwelling budget therefore treats demolition and enabling works as a defined line with its own contingency, rather than a small footnote to the construction cost.

The construction of the new house is by far the largest cost in a replacement dwelling, and it is worth being specific about the range rather than quoting a single figure. For a good-quality, architect-designed new house in London and the South East, construction costs in 2025 typically run somewhere between roughly £2,500 and £4,000 per square metre of internal floor area, before VAT, professional fees, demolition and site-specific extras. Richmond sits firmly in that London band, and higher specifications, difficult sites or premium finishes push toward and beyond the top of it — genuinely high-end homes in the borough can exceed £5,000 per square metre.

What sits inside that per-square-metre figure is a whole house built to modern standards: foundations and ground floor, superstructure (masonry, timber frame or steel as appropriate), roof, external envelope and windows, full internal fit-out, kitchen and bathrooms, heating, hot water, ventilation, electrics and drainage, and external works around the building. A new build carries costs an extension does not — a complete set of foundations, a full roof, the entire external envelope, and all the services from scratch — which is why the per-square-metre rate for a whole house is higher than for adding a room to an existing one.

The specification is the biggest single variable within the range. A well-built but relatively standard family house sits toward the lower end; a house with high levels of glazing, natural stone, hardwood, bespoke joinery, a basement, a swimming pool, home automation or landscaped grounds sits far higher. In Richmond, where end values are high and buyers expect quality, replacement dwellings often sit in the upper part of the range because the finished home is designed to a standard that the location and the plot value justify. It is essential to set the specification realistically at the budgeting stage, because it moves the total more than almost anything else.

Ground conditions and the site itself are the other big swing factor. Richmond's proximity to the Thames means that parts of the borough have high water tables, alluvial or made ground, and flood-risk considerations, all of which can drive up foundation costs — piled or raft foundations, or a raised finished floor level, cost considerably more than simple strip footings on firm ground. A basement, increasingly popular on constrained high-value plots, adds very substantial cost and complexity, particularly near the river. We assess ground conditions and flood risk early, because they can move the construction budget by tens of thousands of pounds and are far better known before you commit than discovered when the groundworks start.

A replacement dwelling is a complete structural design exercise, from the ground up, and on many Richmond plots the ground is the most demanding part. Crown handles the structure alongside the architecture and the building services, so the design you take to planning is a coordinated, buildable scheme rather than a set of layouts that an engineer has yet to make stand up. On a new house that integration matters, because the structural strategy, the foundation choice and the ground conditions interact directly with the cost.

Foundations are the first structural decision and often the most expensive. The right solution depends on the ground: firm, well-drained ground close to the surface may allow conventional strip or trench-fill foundations, while soft, variable, made or waterlogged ground — common near the Thames and its tributaries — often calls for a reinforced raft, a piled foundation, or deeper footings, each of which costs considerably more. The proximity of trees is another driver: Richmond's leafy streets are full of mature and protected trees, and building near them can require deeper foundations to manage the effect of tree roots on shrinkable clay soils, which the National House Building Council guidance addresses in detail.

Above ground, the structural design has to deliver the architecture: open-plan living spaces, large glazed openings, cantilevers, roof terraces and generous spans all need proper structural resolution — steel or engineered timber where masonry alone will not do. A new house designed to modern expectations, with the light and openness people want, places real demands on the structure, and those demands have to be resolved at design stage so they are costed and buildable, not discovered as a problem on site. The choice of primary structure — masonry, timber frame, steel frame or a hybrid — also has cost, programme and energy implications that are best decided early.

Because we design the structure in step with the architecture, the drawings that go to planning already reflect a buildable scheme, and the transition into the detailed structural design and Building Regulations submission is smooth rather than a fresh round of redesign. On a replacement dwelling near the river, where foundations and flood-resilient construction can be the difference between a viable budget and an unviable one, that early structural thinking is one of the most valuable things a coordinated design team brings.

A new dwelling needs a complete set of building services designed from scratch — heating, hot water, ventilation, electrical power and lighting, water supply and drainage — and on a modern, low-carbon house these are more integral to the design than they used to be. Crown designs the services alongside the architecture and the structure, so that plant, pipework, ducting and cabling are planned into the building rather than squeezed in afterwards, which affects both cost and how well the finished house performs.

Heating and hot water are the headline services, and the direction of travel is clear: new homes are moving decisively toward low-carbon heating, principally air-source heat pumps, driven by the Building Regulations and the forthcoming Future Homes Standard. A heat pump changes the design — it needs external space for the unit, a hot-water cylinder inside, and a heat-emitter strategy (larger radiators or underfloor heating) suited to lower flow temperatures — and those requirements are best designed in from the start. Underfloor heating on the ground floor, well insulated, pairs naturally with a heat pump and is common in new Richmond homes.

Ventilation is the service most often underestimated. A modern, airtight house needs a proper ventilation strategy to stay healthy and avoid condensation and mould — frequently mechanical ventilation with heat recovery (MVHR), which recovers warmth from extracted air and is genuinely effective in a well-sealed home, but which needs ducting routes designed into the structure. Get the ventilation design wrong and a well-insulated house can suffer damp and poor air quality; get it right, and it is comfortable and efficient. Water and drainage complete the picture: a new house needs a designed drainage strategy, and on plots near the Thames, surface-water and flood-resilient drainage design (including sustainable drainage) is an important part of both the planning case and the build.

The wider electrical and smart-home fit-out — lighting design, power, data, security, provision for electric-vehicle charging and future solar photovoltaic panels — is where specification, and therefore cost, varies most. A new house is the ideal opportunity to design these in properly, and doing so at design stage is far cheaper and neater than retrofitting later. We size and coordinate the services to the house and the client's brief, so the mechanical and electrical strategy supports the architecture and meets the energy standards without unwelcome surprises during construction.

Every new dwelling must meet the energy and carbon requirements of Part L of the Building Regulations, and compliance is demonstrated through a SAP (Standard Assessment Procedure) calculation — an energy model of the house prepared at design stage and confirmed on completion, which also produces the Energy Performance Certificate. For a replacement dwelling this is a whole-house energy exercise, not the lighter approach that applies to extensions, and it shapes the fabric, the glazing, the heating and the ventilation from the outset. Building a new house to the current standard already means high levels of insulation, good airtightness, efficient glazing and low-carbon heating.

The bar is rising. The Future Homes Standard, confirmed by the Government and due to take effect through amendments to the Building Regulations, is designed to make new homes 'zero carbon ready' — emitting far less carbon than homes built to older standards and requiring no retrofit to become zero-carbon as the electricity grid decarbonises. In practice the Future Homes Standard means low-carbon heating (effectively heat pumps rather than gas boilers), very high fabric performance, and — under the accompanying changes — on-site renewable generation such as solar photovoltaic panels on the majority of new homes. Compliance will be demonstrated through an updated version of SAP. The standard comes into force through the 2025-27 regulatory cycle, with the new requirements applying to new homes from 24 March 2027 and a transitional period following.

For anyone designing a replacement dwelling in Richmond now, the sensible approach is to design to at least the current Part L standard and, where the programme runs into the Future Homes Standard's introduction, to design to that higher bar so the house is genuinely future-proof. Practically, that means a well-insulated, airtight fabric, an air-source heat pump, mechanical ventilation with heat recovery, good glazing with solar-control where needed, and provision — or actual installation — of solar PV. These measures add cost over a bare-minimum build, but they lower running costs dramatically, improve comfort, and protect the home's value, and on a new house they are far cheaper to build in than to retrofit later.

The energy strategy is not a bolt-on; it is woven through the architecture, the structure and the services. The orientation and glazing, the insulation and airtightness detailing, the heating and ventilation, and the renewable generation all have to work together, and the SAP calculation is the tool that proves they do. We integrate the energy design from the first sketch so the house meets — and ideally exceeds — the required standard efficiently, rather than reaching for expensive last-minute add-ons to scrape a pass on the SAP.

Richmond upon Thames is defined by its river, and that shapes the drainage and flood-risk side of a replacement dwelling more than in most boroughs. Substantial parts of the borough lie within Environment Agency flood zones associated with the Thames and its tributaries, and where a plot is in a higher flood zone, the replacement dwelling has to be designed to be safe and resilient — often with a raised finished floor level, flood-resilient construction at ground level, and a demonstration through a flood risk assessment that the development is appropriate and does not increase flood risk elsewhere. Where a flood risk assessment is required, it is both a report cost and a genuine design constraint.

Surface-water drainage is the other half of the picture, and national and London policy now expect new development to manage rainwater on site through sustainable drainage systems (SuDS) rather than simply piping it to the sewer. On a replacement dwelling that means designing in permeable paving, soakaways, rain gardens, attenuation storage or green roofs as appropriate, so that the new house does not increase run-off compared with the site as it was. A well-designed SuDS strategy is part of a strong planning case and, on a constrained urban plot, needs careful thought to fit alongside the house, the garden and the trees.

Foul drainage for a new house connecting to the mains is usually straightforward in an urban borough like Richmond, but the connection has to be designed and, where it crosses or connects to a public sewer, agreed with the water authority. Where a new or altered connection, or a build near a public sewer, is involved, a build-over agreement may be needed. These are process items that a good design coordinates early so they do not delay the build.

We assess flood risk and drainage at feasibility, because on a riverside plot they can materially affect both the design and the cost — a high water table or a flood-zone location changes the foundations, the floor levels and sometimes the whole feasibility of a scheme. Understanding the water context of a specific Richmond plot before committing is part of an honest appraisal, and it is one of the areas where the borough's particular geography really matters.

Richmond upon Thames is unlike anywhere else in London: the only borough to straddle the Thames, and among the greenest and most sought-after in the capital. It stretches from Kew and Barnes in the north-east, through Richmond itself, Twickenham, Teddington, Ham and Petersham, to Hampton and Hampton Court in the south-west, and it is bound together by the river that curves through it. Richmond Park — the largest of London's Royal Parks — the Royal Botanic Gardens at Kew, Hampton Court Palace, Ham House, Marble Hill and the protected view from Richmond Hill (the only view in England safeguarded by its own Act of Parliament) give the borough a landscape and heritage setting of national importance.

The borough as it exists today was formed in 1965, when the municipal boroughs of Richmond, Twickenham and Barnes were brought together; Kew, Petersham and North Sheen had joined Richmond in 1892, and Ham in 1933. That layered history is written into the housing stock. Richmond has grand Georgian and Victorian houses around Richmond Green, Richmond Hill and the riverside; Arts and Crafts and Edwardian suburban streets; interwar and post-war housing across Twickenham, Teddington and Hampton; and pockets of modern infill throughout. It is a borough of individual houses on individual plots as much as terraces and mansion blocks, and that plot-by-plot character is exactly what makes replacement dwellings a recurring project type here.

That variety is planning-relevant, not just scenic. Much of the borough is covered by conservation areas — Central Richmond, Richmond Hill, Richmond Green, Richmond Riverside, Twickenham Riverside, Kew, Ham Common, Broom Water in Teddington and many more — and within them the character of the existing buildings, rooflines, materials and boundary treatments carries real planning weight. Elsewhere, in the interwar and post-war suburbs, the character is more varied and the scope for a well-judged contemporary replacement can be greater. Knowing which kind of context your plot sits in is the starting point for both the design and the cost.

For a replacement dwelling, this context is decisive. A tired post-war house on a generous plot in a suburban part of Teddington or Hampton is a very different proposition from a modest house in the Richmond Hill or Kew conservation areas, where every aspect of a replacement will be scrutinised against the historic character. Both can be excellent projects, but they carry different design constraints, different report requirements and therefore different costs. Understanding where your plot sits in Richmond's remarkable geography and heritage is where a credible appraisal begins.

Replacement dwellings have become a significant part of how Richmond's housing stock evolves, and the reasons are specific to this borough. Land is scarce and expensive, the Green Belt and Metropolitan Open Land put a firm edge on the borough, and large-scale development sites are few. In a borough that is essentially built out and fiercely protective of its character, the way new and better homes are most often delivered is not on green fields but on existing residential plots — by extending, by subdividing, and, increasingly, by replacing houses that no longer serve their plots well.

The stock itself drives the trend. Alongside Richmond's celebrated period houses sits a large quantity of interwar and post-war housing — solid enough in its day, but often poorly insulated, awkwardly laid out, and modest relative to the plots it occupies. As families' expectations of space, light and energy performance have risen, and as the cost of deep retrofit and extension has climbed, replacing a dated house with a well-designed new one has become an increasingly rational choice, especially where the plot's value justifies a high-quality build.

Policy has shaped the pattern too. Richmond's planning approach has long been protective — of character, of trees, of the river setting, of neighbours' amenity — and successive Local Plans, culminating in the plan adopted in October 2025, have set a high bar for the design of new houses. That has professionalised the replacement-dwelling process: the schemes that succeed are carefully designed to respect their context, to protect amenity, and to demonstrate genuine quality, while poorly considered 'bigger box on the plot' proposals are routinely refused. The result is a borough where replacement dwellings are common but where they have to be done properly.

Understanding this history helps you understand the council's mindset. Richmond is not opposed to replacement dwellings — it consents many — but it expects them to improve on what they replace: to sit comfortably in the street, to respect the character and the river setting, to protect neighbours, and to deliver a genuinely better home. An application that reflects that expectation is the one that succeeds. That is the difference between a replacement dwelling designed to be approved and one that is simply hoped through, and it is the approach we bring to every Richmond plot we work on.

The design of the new house is where a replacement dwelling delivers its value, and it has to satisfy two things at once: the standards that make a home genuinely liveable, and the character and amenity tests that get it consented. On the standards side, the London Plan's nationally described space standards (NDSS) set minimum internal floor areas for new homes by number of bedrooms and occupants, along with minimum room sizes, storage and ceiling heights. A well-designed replacement dwelling comfortably meets and usually exceeds these, but they are the floor below which a new home should not fall, and they inform the layout from the start.

Good layout is about far more than hitting minimum areas. It is about how the house works — the flow between spaces, the relationship of living areas to the garden, the quality of daylight in every room, storage, accessibility, and how the house will adapt as a family's needs change. A replacement dwelling is a rare chance to design a home from scratch around the way you actually live and around the specific plot — its orientation, its outlook, its trees, its levels — rather than working within the compromises of an existing house. That freedom is the single biggest advantage of replacing over extending.

The external design is where the planning case is won. In Richmond, the new house has to respond to its context: its scale and massing judged against neighbours and the street, its rooflines, materials, fenestration and boundary treatments considered against the character of the area, and its impact on any protected view or the river setting carefully handled. In a conservation area that usually means a design of real sensitivity, often referencing local materials and proportions; in a more varied suburban context there can be scope for a confident contemporary house. Either way, the design has to be resolved, not generic, because Richmond judges design quality closely.

Amenity design runs right through the layout and the elevations. Window positions, the height and position of flank walls, the depth and height of the building relative to boundaries, and the treatment of overlooking all have to protect neighbours' daylight, sunlight, privacy and outlook — the tests Richmond applies rigorously. We design to these from the first sketch, testing the massing against the neighbours and the street, so that the scheme that goes to the council is one that respects its context and its neighbours and is therefore capable of approval, rather than one that maximises floor area at the expense of the very tests that decide it.

A replacement dwelling needs a full, coordinated set of drawings and supporting documents, and we prepare them through the recognised RIBA work stages so the project moves in a logical order from idea to building. It begins with an accurate measured survey of the existing house and the plot, and often a topographical and tree survey, because the case for a replacement — and the assessment of it — rests on showing clearly what is there now and what is proposed to replace it. Existing plans, elevations and sections record the house to be demolished; the proposed drawings show the new dwelling in full.

For the planning application, the package normally includes a location plan and site plan, existing and proposed floor plans, elevations and sections, a comparison showing the new house against the old one, a design and access statement setting out the design rationale, and the supporting reports the site requires — commonly an arboricultural (tree) report, a flood risk assessment where the plot is in a flood zone, a biodiversity/ecology assessment and a biodiversity net gain assessment, a daylight/sunlight assessment where neighbours are close, and a heritage statement in a conservation area or near listed buildings. Which of these apply depends on the plot, and identifying them early keeps the application complete and avoids delay at validation.

Once permission is granted, the design develops into the technical and construction stages: the detailed structural design and calculations, the building services (MEP) design, the energy/SAP calculations, and the full set of construction drawings and specifications that the Building Regulations require and that your builder needs to price and build accurately. Because we carry the architecture, structure and services through together, this stage builds on the consented design rather than reworking it, which protects both the programme and the budget.

Everything is prepared to be internally consistent — the structural strategy matches the architecture, the SAP model matches the fabric and services shown on the drawings, the drainage strategy matches the flood and SuDS reports, and the amenity design matches the daylight assessment. A coordinated, self-consistent set of information is materially more likely to be approved and much less likely to generate costly problems on site than a collection of drawings and reports that do not quite agree with one another.

The process starts with feasibility, and on a replacement dwelling it is where the project is really decided. We survey the house and plot, establish the planning history and the designations that apply — conservation area, listing, protected views, the Thames Policy Area, flood risk, tree preservation orders — and test what a replacement dwelling can realistically be in terms of size, height and massing against Richmond's Local Plan. Crucially, we also model the numbers at this stage: the build and demolition cost, and the CIL calculation net of the existing-dwelling offset, so you know early whether the project stacks up. This is where we give you an honest view before you spend money on a full design or commit to a purchase.

With feasibility settled, we develop the design and, where the plot is sensitive or the scheme finely balanced, we often recommend pre-application advice from Richmond. Pre-app carries a fee and adds a few weeks, but on a replacement dwelling in a conservation area or a prominent location it can be genuinely worthwhile: a written steer from the council on scale, design and acceptability reduces the risk of a wasted full application and signals to the eventual case officer that the scheme has been thought through. We advise on whether it is worth it for your specific plot rather than treating it as automatic.

We then prepare and submit the full planning application through the Planning Portal and manage it through validation and determination — responding to the case officer, providing additional information, negotiating amendments where that will secure approval, and handling any consultation responses from neighbours and statutory consultees. Householder-scale applications run against an eight-week target, but a full application for a new dwelling can take longer, particularly where it is contested or in a sensitive location, and where it goes to committee. We keep you informed and steer the application toward a positive decision.

Once planning permission is granted, we deal with the CIL formalities (the assumption of liability, any relief or exemption claim, and the commencement notice, all in the correct order and at the correct time), discharge any pre-commencement planning conditions, and prepare the Building Regulations application and construction information. Building control can be handled through the council or an approved inspector, and we coordinate the structural, services and energy design so the build is fully specified. The aim is a smooth path from consent to a house being built, with the same team that won the permission carrying it through to construction.

A credible replacement-dwelling budget is built from the parts, not from a single headline number, and it is worth setting them all out. The main components are: demolition and enabling works (commonly around £10,000–£30,000, more with asbestos or difficult access); the new-build construction (typically £2,500–£4,000+ per square metre, so a 200 square metre house sits in a broad band of roughly £500,000 to £800,000-plus for the build alone, higher for premium specifications); professional fees (architecture, structural engineering, building services, energy assessment, and the specialist reports the site needs); the CIL, net of the existing-dwelling offset and any self-build exemption; VAT; and a contingency.

The council's own fees are the smallest part. A full planning application for a new single dwelling carries a fixed application fee that runs to a few hundred pounds, and any pre-application advice or Building Regulations charge is likewise modest relative to the whole. These are worth knowing but they do not move the total — the money is in the demolition, the build and the fees, and in the CIL where it applies. We set out every figure, including our own fixed fee for the design and application work, at the start so there are no surprises.

The CIL line is where a replacement dwelling differs most from a new house on a bare plot, and it is worth restating in a costing context. Because the demolished home's floorspace is deducted, and because the self-build exemption may remove the borough CIL entirely for an owner-occupier, the CIL on a like-for-like replacement is frequently far smaller than the headline rate suggests — sometimes little or nothing. A CIL figure calculated on the full floorspace of the new house, ignoring the offset, is one of the most common ways a replacement-dwelling appraisal is made to look worse than it really is. Getting this right is central to an honest budget.

VAT deserves a specific word, because it works differently on a replacement dwelling than on an extension. The construction of a genuinely new dwelling is generally zero-rated for VAT — you do not pay 20% VAT on the qualifying construction of a new house, unlike work to an existing dwelling, which is usually standard-rated. That zero-rating is a significant saving and a real advantage of replacing over extending, though it depends on the old building being wholly demolished and the work qualifying under HMRC's rules (VAT Notice 708). It should be confirmed for your specific project, but for most replacement dwellings the new-build work is zero-rated, which materially improves the all-in figure. Finally, allow a proper contingency — on a new build, typically around 10–15% — because groundworks and existing-site surprises are the usual source of cost overruns.

One of the biggest financial advantages of a replacement dwelling over an extension is VAT. Work to an existing house is generally charged at the standard 20% VAT rate, but the construction of a genuinely new dwelling is, in most cases, zero-rated under HMRC's rules for buildings and construction (VAT Notice 708). Because a replacement dwelling involves demolishing the old house entirely and building a new one, the qualifying construction of that new house is usually zero-rated — meaning you do not pay VAT on the build, a saving that can run to a very large sum on a six- or seven-figure project.

The zero-rating is not automatic and depends on the facts. As a general rule the existing building has to be demolished completely to ground level for the new house to count as new construction — retaining a significant part of the old house (a common way people try to save on demolition) can jeopardise the zero rating and turn the whole build into standard-rated work. There are limited exceptions where a single facade must be retained as a planning condition, but the safe position for the VAT saving is a genuine, complete replacement. This is one reason the demolition strategy and the VAT position have to be considered together.

The zero rate applies to the services of the builder constructing the new dwelling and to qualifying building materials supplied with those services. Where you are engaging a main contractor, the contractor charges the qualifying work at zero per cent; where you are managing the build yourself and buying materials, the DIY Housebuilders' Scheme may allow you to reclaim the VAT on eligible materials. Structuring the project and the contracts to capture the zero rating correctly is part of controlling the true cost, and it is an area where the rules reward doing things properly.

The broader point is that the headline construction-cost-per-square-metre figures quoted earlier are usually stated before VAT, and because a replacement dwelling is generally zero-rated, the correct VAT treatment makes a large difference to the all-in number in your favour. Pricing a replacement dwelling as though it carried 20% VAT overstates the cost significantly. We flag the VAT position at the budgeting stage and recommend confirming the detail with a VAT-aware accountant on larger schemes, but for most Richmond replacement dwellings the new-build work is zero-rated, and that is a genuine, sizeable saving.

Understanding why replacement-dwelling applications fail in Richmond is the best way to make sure yours does not, and most refusals come down to a handful of recurring issues. The most common is scale and massing: a proposed house that is significantly larger, taller or bulkier than the one it replaces, or than its neighbours, and that harms the character of the street or the area. Richmond judges the relationship of a new house to its context closely, and an over-scaled 'bigger box' is one of the quickest routes to a refusal, however well finished.

Amenity harm to neighbours is the second big reason. A replacement dwelling that is positioned, angled or scaled so that it overshadows a neighbour's garden or windows, overlooks their private space, or creates an oppressive sense of enclosure will fall foul of Richmond's detailed amenity policies. Because the new house is a fresh design rather than an extension of the old one, it can introduce impacts the previous house did not, and if those impacts are not designed out, refusal follows. This is entirely avoidable with a design that tests the massing against the neighbours from the start.

Design quality and character are the third, especially in conservation areas and near the river or protected views. A replacement dwelling that fails to respond to the local character — wrong materials, wrong proportions, wrong rooflines, or a generic design that could be anywhere — struggles in a borough that expects genuine design quality. In a conservation area, harm to the character or appearance of the area, or the loss of a building that positively contributes to it, can be decisive. Trees are a further recurring issue: harm to protected trees, or a scheme that cannot be built without damaging them, is a common ground for refusal in leafy Richmond.

Beyond these, flood risk (a scheme that is not safe or that increases flood risk), inadequate drainage or SuDS, insufficient supporting information (missing a required report), and highways or parking concerns all feature. Our approach is to anticipate every one of these reasons and answer it in the application itself, and to be honest at feasibility where a scheme is likely to fail one of them. A refusal costs fees, time and momentum, and a well-designed, well-evidenced replacement dwelling that respects its context and its neighbours is far more likely to be approved first time.

To make the numbers concrete, consider a common Richmond scenario: a tired 1950s detached house of around 120 square metres on a generous plot in a suburban part of Teddington, in the south-west of the borough, which the owners want to demolish and replace with a well-designed 200 square metre family home to live in themselves. It is exactly the kind of plot where a replacement dwelling makes sense — the existing house is small, poorly insulated and badly laid out relative to its land, and a new home would transform the way the family lives while adding real value.

At feasibility, we survey the house and plot, check that it is not in a conservation area or affected by listing or a protected view, assess the trees and any flood risk, and test what scale of replacement the street and neighbours can support under Richmond's Local Plan. Because Teddington sits in the south-west charging zone, the borough CIL base rate is £190 per square metre (indexed to roughly £310.84 per square metre for 2025) plus Mayoral CIL. Crucially, the existing 120 square metre house has been lived in and is in lawful use, so its floorspace is offset: CIL would otherwise be charged on 200 square metres, but the offset reduces the chargeable floorspace to about 80 square metres — and because the owners are building their own home to live in, the self-build exemption can remove the borough CIL entirely, provided the forms and commencement notice are handled correctly.

On cost, we build the estimate from the parts. Demolition of the modest detached house, allowing for an asbestos check, sits toward the lower end of the £10,000–£30,000 range. The new 200 square metre house, designed to a good family-home specification with a heat pump, MVHR and high fabric performance for the Future Homes era, at, say, the middle of the £2,500–£4,000 per square metre range, puts the build itself in a realistic band well into the mid-hundreds of thousands. We add professional fees, the specialist reports the plot needs (arboricultural and drainage in particular), and a 10–15% contingency for groundwork surprises. Importantly, the qualifying construction of the new dwelling is zero-rated for VAT, and the CIL is minimal once offset and exemption are applied — two facts that materially improve the all-in figure.

On the planning side, we prepare the measured survey, existing and proposed drawings including an old-versus-new comparison, a design and access statement, and the tree, drainage/flood and biodiversity information the plot requires, designed from the outset to protect the neighbours' daylight, sunlight and privacy. Submitted through the Planning Portal and managed through Richmond's process, a scheme like this — a genuine improvement on a poor house, scaled to its context, protecting its neighbours, and delivering a modern low-carbon home — goes in as a proposal the council can approve. Once permission is granted, the same coordinated team carries the structural, services and Building Regulations design through to construction. That is the difference between a replacement dwelling designed to succeed and one that is simply hoped through.

Cost only makes sense alongside value, and in Richmond the value side of a replacement dwelling is unusually strong. The borough is one of the most desirable residential locations in London, with high and resilient house prices, and a well-designed modern home in a good Richmond, Teddington, Twickenham or Kew location commands a substantial value. A replacement dwelling that turns a tired, inefficient house into a coherent, contemporary, energy-efficient family home can therefore support a significant build budget and still deliver a genuinely valuable asset — often far more valuable than the same money spent extending and patching the existing house.

That said, viability is not automatic, and the appraisal has to be honest. The costs on this page — demolition, build, fees, reports, CIL (net of offset and exemption), VAT and contingency — have to be weighed against the realistic end value and the cost of the plot. The risk is paying too much for the plot, or under-budgeting the build and the groundworks, so that the finished house is worth less than it cost to create. This is precisely why feasibility and a realistic, parts-based budget before you commit are the best money you can spend.

The CIL and VAT positions feed directly into viability, and they usually work in a replacement dwelling's favour. The existing-dwelling offset and the potential self-build exemption keep CIL low, and the zero-rating of new-build construction removes the 20% VAT that an extension would carry. Together these can make a replacement dwelling markedly more viable than the headline costs suggest — but only if they are understood and claimed correctly, which is why they belong in the appraisal from the start rather than being discovered at the end.

We approach every Richmond replacement dwelling as a cost-and-value question, not just a design one. We tell you honestly what the project is likely to cost, built from the parts, how the CIL and VAT play out, and how the total stacks up against the realistic end value — so you can make the decision on facts rather than on optimism. For the right plot and the right house, the numbers in Richmond are genuinely attractive; for the wrong one, they are not, and it is far cheaper to find that out at feasibility than after demolition has started.

Crown Architecture designs replacement dwellings across Richmond upon Thames and the surrounding boroughs, and we do it as a single coordinated service: the planning and design, the structural engineering and the building services under one roof. On a whole new house that integration matters enormously, because the architecture, the foundations and structure, the services and the energy strategy are completely interdependent — design them separately and they clash, and on a new build near the Thames, where foundations, flood resilience and low-carbon services are decisive, a clash can be expensive.

We know the Richmond context: the new Local Plan adopted in October 2025 and its character-based approach, the many conservation areas, the protected views and the river setting, the borough's rigorous amenity tests, the tree protection, and the flood-risk and ground conditions that come with a riverside borough. We use that knowledge to give you honest advice at feasibility — before you buy, ideally — and to design replacement dwellings that respect their context and their neighbours and are therefore designed to be approved rather than hoped through.

Just as importantly, we are straightforward about cost. We build estimates from the parts — demolition and enabling works, the new-build construction, professional fees and reports, CIL net of the existing-dwelling offset and any self-build exemption, VAT at the correct (usually zero) rate, and a proper contingency — rather than quoting a single misleading figure, and we tell you where the risks and surprises are likely to be. We quote a clear fixed fee for our own work and prepare a coordinated, self-consistent application that a case officer can approve without having to fill in gaps.

We also stay with the project after the drawings are done. We manage the planning application through Richmond's process, handle the CIL forms and any exemption in the right order and at the right time, discharge conditions, and carry the scheme into the Building Regulations and construction information your builder needs — coordinated with the structural and services design so it is genuinely buildable. The aim is a single, accountable point of contact from the first survey to a finished, valuable home, rather than a set of drawings handed over and a client left to navigate the borough's constraints and the CIL rules alone.

If you are considering a replacement dwelling in Richmond upon Thames — whether it is a post-war house on a generous suburban plot or a sensitive project in a conservation area — send us the address and what you have in mind, and we will tell you honestly whether it is achievable, roughly what it will cost including the demolition and the CIL position, and how to get there.