BIMBY
Multiplying gardens
BIMBY: build, plant, garden — making the city of tomorrow, one plot at a time
BIMBY — an acronym for "Build In My Back Yard" — is an urban planning approach that lets cities and towns densify and green themselves progressively, plot by plot, driven by the initiative of their own residents. It's a gentle-densification housing method compatible with France's Zero Net Land Take (ZAN) target, developed and tested since 2013 by Villes Vivantes with hundreds of pioneering French municipalities.
The principle: thousands of single-family homeowners have untapped land potential sitting in their own gardens. BIMBY activates that potential — by building a new home on the plot, or by splitting off part of it to sell as a buildable lot. In doing so, gardens don't disappear: they're shared, planted, brought back to life.
A large garden that's become too much for an ageing owner to maintain is reshaped into two or three human-scale gardens, tended by new families. More houses, more gardeners, more biodiversity.
Multiplied across an entire city, these projects add up to a powerful lever for urban transformation — without sprawl, without demolition, without massive top-down projects. But BIMBY isn't just spontaneous plot-splitting: it's a method of organic urbanism, orchestrated by the local authority, which sets the regulatory framework and organises support for every resident with a project.
BIMBY is a city that densifies, greens, and diversifies all at once. A way of building the city with its residents, rather than simply for them.
The BIMBY principle: turning one garden into two, three or four, widening access to the individual house without urban sprawl.
Two scenarios, thousands of options, one logic
BIMBY rests on a single principle — building a new, self-contained structure on an already-built plot — but comes in two main scenarios. In both cases, a somewhat neglected garden is shared, reshaped, and given a new lease of life with new occupants. In both cases, it's the local authority that creates the conditions for it to happen, by adapting its planning rules and setting up a support service. BIMBY doesn't exist without that framework.
Scenario 1 — I build in my own garden
The owner stays in control of their plot and has a new home built — a house, a small house, a studio, sometimes an office — for a wide range of uses:
✼ moving into it themselves for their retirement years, handing the main house to a younger family who will renovate it, while settling into a single-storey home with a smaller, easier-to-maintain garden;
✼ housing a child, a parent or a relative nearby, sharing the garden and summer barbecues;
✼ creating a rental unit to supplement their income.
The existing building is kept, sometimes renovated, and the garden is reorganised and shared. The new residents bring a fresh eye and new energy to caring for the garden!
Scenario 2 — I sell part of my garden as a buildable lot
The current owner splits off part of their plot and sells it to a newcomer — a family, a couple, an individual — who in turn becomes a builder and gardener on that land. The newcomers will build to live there or to rent out, and cultivate their own garden.
Double benefit: the original owner ends up with a more manageable garden they can finally tend properly. And the area gains a new household settling into an already well-served neighbourhood — plus a new gardener.
In the Pau conurbation: one plot, two complementary logics. BIMBY creates a new building in the garden; BUNTI transforms the existing one. The two options are always explored together and can be combined into a single project.
BIMBY and BUNTI: building new and transforming the existing — two approaches that often go hand in hand
BIMBY is distinct from BUNTI, the other major method developed by Villes Vivantes:
✼ BIMBY = creating a new, self-contained building on an already-built plot;
✼ BUNTI = transforming the existing building itself: extension, adding a storey, interior reconfiguration, renovation, change of use.
In practice, local authorities very often launch BIMBY-BUNTI operations through a single integrated service that offers landowners the full range of options. For every resident the team meets, all options are explored together — building in the garden, transforming and renovating the existing home, or both — and it's the owner who chooses based on their needs, project, means and preferences.
Périgueux, BIMBY operation run by Villes Vivantes (2016–2021) — two additional houses built on the plot of an old house that was up for sale, allowing the city to densify without sprawling and to bring families back to the town centre.
The local authority's role: setting the framework and organising support
BIMBY doesn't work without a strong commitment from the local authority. Its role has two parts.
The first is setting the rules of the game: adapting the local land-use plan (PLU) to authorise and frame gentle-densification projects, and defining qualitative guidelines by type of urban fabric — including the place of greenery and gardens in new projects.
The second is organising support: setting up a service, or mandating an operator — such as Villes Vivantes — to reach out to residents, identify potential projects, and support each project owner from the initial idea through to construction, which will be carried out by local real-estate and building professionals.
The local authority doesn't design the projects itself: it creates the conditions that let residents bring them to life. It becomes the conductor of a distributed urban transformation — denser, greener, more diverse.
Prospective buyers visiting a BIMBY plot: future neighbours and gardeners — Périgueux, Villes Vivantes, 2018.
The residents' role: builders, gardeners, partners
Owners, families, local entrepreneurs: in a BIMBY project, residents aren't simply beneficiaries of an urban project designed for them. They're its authors — both the project owner for the construction (which they'll entrust to a builder, an architect or a project manager) and the gardener.
Every BIMBY project is driven by an owner who decides the shape of their building, how their garden is organised, what species they plant. And every newcomer who settles on a subdivided plot becomes, in turn, a new resident of the town as well as the active steward of a small patch of nature in the city. It's this diversity of perspectives and hands that gives BIMBY-transformed neighbourhoods their ecological and typological richness.
The result is a city that looks like its residents: dense, green, diverse and alive.
In Périgueux, as part of the BIMBY operation run by Villes Vivantes between 2016 and 2021, a leftover 75 m² space — until then the parking spot of the owner of the house on the left — now holds 1/ a terrace opening onto a new picture window that brings fresh light and an outdoor space with a view to the existing house, 2/ the parking space, kept, and 3/ two studio flats rented to medical students, sharing a common patio. 250 new housing projects were granted permission this way in 5 years.
How does a BIMBY operation unfold?
A BIMBY operation (often launched jointly with BUNTI) is structured in several complementary phases:
✼ Territorial diagnosis and gentle-densification potential study: analysis of the plot pattern and built fabric, identification of relevant perimeters, definition of a strategy tailored to each neighbourhood — factoring in greening and biodiversity, adapting housing to an ageing population, access roads, networks, and accessibility to jobs, services and amenities.
✼ Regulatory adjustment: revising or adapting the PLU to authorise gentle-densification projects and define
qualitative guidelines, particularly on the place of gardens and living things, insertion conditions, parking, and optimising building placement and urban form with a bioclimatic design approach, etc.
✼ Defining an operation perimeter and setting up a resident-outreach system: a website and a booking platform (in person or online), live "design workshop" sessions, on-site office hours, local communication — to identify project owners and explore, together with them, the potential of their plot, buildings and garden.
✼ Project support: individualised follow-up for every project owner, from the first idea through to completion, including obtaining planning permission. For each resident, every BIMBY and BUNTI option is explored together.
✼ Monitoring and evaluation: measuring results (projects designed, supported, authorised, delivered), continuously adjusting the strategy.
Support mandate for the Périgueux BIMBY operation: the city mandated Villes Vivantes to support every project owner who wanted it. France's first large-scale BIMBY operation, led by Villes Vivantes for the city of Périgueux between 2016 and 2021, with 250 new-housing projects authorised in 5 years (half in BIMBY, half in BUNTI).
The first large-scale BIMBY operation in France, run by Villes Vivantes for the city of Périgueux between 2016 and 2021: 250 new housing projects granted permission in 5 years (half BIMBY, half BUNTI).
BIMBY produces homes, terraces and balconies, gardens and gardeners
Since 2013, Villes Vivantes has run BIMBY-BUNTI operations in dozens of French municipalities. Results show that a well-run operation can generate several hundred housing projects in a single area — and just as many new gardeners active in the existing urban fabric.
In Périgueux, between 2016 and 2021: 250 housing projects were authorised, half in BIMBY and half in BUNTI. Projects of every size — a studio in a garden, a family home on a subdivided plot, a single-storey home on one's own land for retirement while keeping the same neighbours — which together transformed the town's urban fabric by adding a new, diverse housing supply, without changing the overall character of the place.
It is the quality of the planning rules written by the local authority into its local plan (PLU) that allows new buildings to sit harmoniously in their context — in particular the option to align them with the street and to build up to the plot boundary.
Gentle, organic densification
Because they're driven by a wide range of project owners and designers, BIMBY projects produce varied, fine-grained urban forms that are often more alive than those from large planned developments. Every new building comes with a reshaped garden, planted according to its new owner's tastes and habits. Once completed, BIMBY projects are often hard to tell apart from the existing fabric: they blend in naturally.
When the local plan (PLU) rules are written for the purpose, and when the local authority sets up an architectural and heritage support service, new BIMBY and BUNTI projects blend organically into the existing fabric — so much so that they are hard to spot once built.
Zero Net Land Take: producing housing without consuming nature
BIMBY makes use of land that's already urbanised, without touching farmland, natural areas or forests. For a local authority, it's one of the most powerful tools for concretely delivering on the ZAN target without giving up on housing residents well: producing housing where infrastructure already exists, on plots already served by utility networks, where residents already go to work, shop, and use local amenities.
The upside of ZAN is that it opens up possibilities for densifying, adapting and greening the existing built fabric.
Affordable housing: diversifying supply without relying on major developers
BIMBY projects are led by private individuals, often at a lower production cost than conventional property-development operations: building your own house on land you've already bought has, for 50 years, been the main tool available to French households for building an affordable family home. BIMBY shifts this self-development model — where the resident is the project owner of their own construction — from the form of a suburban subdivision to on-demand, made-to-measure infill housing, produced by families as well as by people looking to build a single-storey home for retirement, a rental unit on land they already own, and so on.
These scattered projects let new kinds of households move into well-located, already well-equipped neighbourhoods, where they'll have access to a garden — a form of access to nature in the city that shouldn't remain a privilege for much longer...
Greening and biodiversity: more houses, more gardeners, more nature
This is the most counter-intuitive phenomenon — and one of the most powerful arguments for launching a BIMBY operation in a given area. The common assumption is that densifying means sealing over land and reducing nature. BIMBY proves the opposite.
As owners age and purchasing power erodes, the large suburban garden often becomes a burden: too big to maintain by hand, it's managed by simplification — mechanical mowing, herbicides, uniformity. A poorly maintained large garden frequently becomes an ecological desert as a result.
BIMBY reverses this logic. By splitting the plot, several human-scale gardens are created, each entrusted to a different household. This change of scale produces three effects:
✼ Ownership through gardening: with a smaller area, the relationship to the land changes. Maintenance-as-a-chore becomes gardening-as-a-choice. It's the ideal scale for rediscovering and actively cultivating living things.
✼ Diversity of gardeners: smaller plots welcome a wider variety of people — families, couples, singles — each bringing their own practices and plants. More gardeners means more attentive intelligence per square metre.
✼ The mosaic effect: ecology teaches us that habitat diversity is essential. Five 200 m² gardens tended by five different gardeners offer far more ecological variety than a single 1,000 m² garden left to the mower.
Recent studies on urban gardens confirm that surface area isn't the deciding factor for biodiversity: it's the richness and layering of vegetation — herbaceous, shrub, tree — that makes the difference. By densifying intelligently, BIMBY gradually builds, with residents themselves, the groundwork for a genuine ecological transition in suburban rings.
Attractiveness and social ties: a city that looks like its residents
By directly involving residents — as builders, as gardeners, as neighbours — BIMBY strengthens their attachment to their neighbourhood and helps produce a living environment that reflects who they are. It mobilises energy and investment that a fully centralised model simply couldn't unlock.
BIMBY is thus much more than a participatory approach: in a sense, it consists of welcoming new residents into the gardens of those who came before them... at their own initiative.
More houses, more gardeners, more planting: gentle densification is the art of turning yesterday's large, under-tended gardens into tomorrow's mosaic of living ones. © David Mathieu | flickr.com
BIMBY and Villes Vivantes' complementary methods
BIMBY is part of a set of four complementary methods developed by Villes Vivantes to deliver organic urbanism across different areas:
✼ BIMBY (Build In My Back Yard): building a new, self-contained structure on an already-built plot — a house, a studio, a small office — through plot-splitting or building at the back of the garden.
✼ BUNTI: transforming the existing building itself — extension, adding a storey, interior reconfiguration, renovation, adapting to present-day needs.
✼ BAMBA: supporting self-development housing dynamics in structured operations, reinventing the dense, freestanding, made-to-measure single-family lot.
✼ BRAMBLE: strategic-intensification operations built on a multitude of small, high-density infill projects, which can include replacing an existing building.
These four approaches have been tested and validated in numerous French local authorities. They can be used separately or combined, depending on the area's challenges. In practice, BIMBY and BUNTI are very often deployed together, as part of the same support service.
Attractiveness and social ties: a city that looks like its residents
By directly involving residents — as builders, as gardeners, as neighbours — BIMBY strengthens their attachment to their neighbourhood and helps produce a living environment that reflects who they are. It mobilises energy and investment that a fully centralised model simply couldn't unlock.
BIMBY is thus much more than a participatory approach: in a sense, it consists of welcoming new residents into the gardens of those who came before them... at their own initiative.
FAQ
What is BIMBY in urban planning?
BIMBY (Build In My Back Yard) is an urban-planning approach that densifies existing suburban fabric through residents' own initiative: building a new home in a garden, or splitting a plot to welcome a newcomer — and a new gardener. It was developed by Villes Vivantes starting in 2013.
BIMBY — what exactly is it, the robot or the urban-planning method?
Both exist! The Bimby food processor is a Vorwerk brand, well known in Italy and Portugal. The BIMBY (Build In My Back Yard) approach is a French urban-planning method, with no connection to the appliance. This page is exclusively about the urban-planning approach.
BIMBY — what happens to the gardens?
BIMBY shares gardens to bring them back to life. A large garden that's become too much for an ageing owner to maintain is reshaped into two or three human-scale gardens, actively cultivated by engaged families. More gardeners means more hands to plant, more plant diversity, more biodiversity. Recent studies confirm that a garden's ecological richness depends more on the quality of its upkeep than on its size.
What's the difference between BIMBY and BUNTI?
BIMBY means building a new, self-contained structure on an already-built plot. BUNTI means transforming the existing building itself: extension, adding a storey, reconfiguration, renovation. In practice, both approaches are very often offered together to residents: the owner chooses, after exploring every option with their support advisor.
Is BIMBY compatible with the ZAN target?
Yes — BIMBY is one of the tools most directly compatible with Zero Net Land Take. It produces housing by using land that's already urbanised — shared gardens, splittable plots — without consuming farmland or natural land.
How do I launch a BIMBY operation in my local authority?
Implementation rests on three levers: adapting planning rules (PLU) to authorise gentle-densification projects, defining a strategy tailored to each type of urban fabric, and setting up a support system for residents with projects. Villes Vivantes supports local authorities through every one of these steps, from diagnosis through to monitoring completed projects.
What results can I expect from a BIMBY operation?
Results vary depending on the area and the intensity of the operation. On operations led by Villes Vivantes, several hundred housing projects are typically identified over a 3–5 year period, a significant share of which reach planning permission. In Périgueux, 250 homes were authorised in 5 years — the equivalent of a very large subdivision or a substantial apartment-block development, produced without public land, without a developer, and right in the heart of the existing town, while preserving and renewing its gardens.