Hampstead Architecture and Planning

Enfield

Garage Conversion Architects in Cockfosters

The usual objection to converting a garage is that it is where everything lives — mower, bikes, tools, garden furniture, the freezer. On a plot with a decent garden that objection has an answer most owners never consider: convert the garage for the space you actually want, and put the storage back as an outbuilding under permitted development.

Last updated

Book an Architectural ConsultationGet your fixed-fee packageor call 020 8054 8756

The short answer

Where does the stuff go if you convert the garage?

Into a properly built outbuilding at the end of the garden, under Class E. The garage is the cheapest habitable space on the plot; the things filling it are incidental storage that does not need to be attached to the house. Design both at once so the services run in one trench — and check the conditions first, because on designated land nothing to the side of the original house is permitted, and anything within two metres of a boundary is height-limited.

Planning at a glance

Cockfosters

Planning at a glance in Cockfosters
Local planning authorityEnfield
Likely approval routeHouseholder planning application or permitted development, depending on conservation status, listing and property type — confirmed for the exact address before drawings begin
Statutory determination time8 weeks for most householder applications (13 weeks for major applications)
Where most projects startPlanning Route Review — £395 inc. VAT, credited in full against your package if you proceed. Find my package →

Take the two moves as one project, because they solve each other. The garage is attached to the house, warm-adjacent, on foundations, with services nearby — which makes it the cheapest habitable space available. The functions currently occupying it are almost all incidental storage, which does not need to be attached to the house at all and is frequently better at the end of the garden, closer to where the mower and the garden furniture are actually used.

Class E is the mechanism, and it is more generous than most people realise. It permits buildings within the curtilage of a house for a purpose incidental to its enjoyment — stores, workshops, garden rooms, home offices — subject to conditions on height, position and the proportion of the curtilage covered. Single storey, with height limits that vary depending on the roof form and how close the building sits to a boundary, nothing forward of the principal elevation, and no more than half the curtilage covered by buildings other than the original house.

The conditions are worth reading properly rather than assumed, because two of them catch people. On designated land — which includes the Trent Park conservation area — nothing to the side of the original house is permitted under Class E, which rules out the most convenient position on many plots. And a building used as habitable accommodation, rather than for a purpose incidental to the enjoyment of the house, is outside Class E altogether: a garden office is generally fine, a self-contained annexe with a bedroom and a bathroom is not.

Build it properly rather than buying a shed. A garden building that will hold a mower and a bicycle needs little, but one intended as a workshop or an office needs a proper floor, insulation, ventilation and power, and building regulations apply depending on its size, its use and how close it sits to a boundary. Designing it at the same time as the garage conversion means the services can be run once and the two buildings can be detailed to look like they belong to the same house.

Local analysis

What matters in Cockfosters

What Class E actually allows

Class E of Schedule 2, Part 1 covers buildings, enclosures and other structures within the curtilage of a dwellinghouse, required for a purpose incidental to the enjoyment of the house. The word incidental is doing significant work and is the source of most confusion. A garden store, a workshop, a home office, a gym, a summerhouse and a garage are all normally incidental. Accommodation in which someone lives — a self-contained annexe with sleeping and bathing facilities, or a building used as a separate dwelling — is not, and building one under Class E on the assumption that it is a garden room is the mistake that leads to enforcement. Working in a garden office is generally fine; sleeping in it regularly changes the character of the use. The physical conditions then constrain what can be built. It must be single storey. The height limits depend on the roof: a dual-pitched roof is allowed more overall height than other forms, and any building within two metres of a boundary is limited to a lower overall height, which is why so many garden buildings end up with a shallow or flat roof when placed close to a fence. Nothing may be forward of a wall forming the principal elevation. And the total area of ground covered by buildings other than the original house must not exceed half the curtilage — a limit that a large existing extension, a garage and a substantial outbuilding can approach on a modest plot, and which is measured against the original curtilage. On designated land the rules tighten in one important respect: nothing to the side of the original house is permitted development, so the position moves to the rear. The practical method is to establish the constraints first and design within them, or to conclude early that an application is needed — which on an undesignated suburban plot is a routine exercise rather than a barrier.

Making the outbuilding worth having

The difference between a garden building that gets used and one that becomes an expensive shed is decided by four things, none of them exotic. Insulation and airtightness come first, because an uninsulated garden room is unusable for most of the year and an uninsulated store gets condensation that ruins what is stored in it. A proper floor build-up with insulation, insulated walls and roof, and reasonable airtightness turn a structure into a room, and on a small building the cost of doing that properly is a modest proportion of the total. Ventilation is second and is the thing most often missing: a well-sealed small building with a person and a computer in it will reach uncomfortable humidity and carbon dioxide levels within hours, so trickle or mechanical ventilation is not optional. Services are third, and they are far cheaper to install in one trench alongside the garage conversion work than as a separate exercise later — power at a capacity that suits the intended use, data if it is an office, and water and drainage only if there is a genuine need, since adding a WC brings drainage design and, potentially, a pumped connection. Position is fourth and is the one that decides how much the building is used: far enough from the house to feel separate if that is the point, close enough that the walk is not a deterrent in February, oriented so the glazing does not turn it into a greenhouse in July, and screened or sited so it does not dominate the garden it sits in. On a plot near parkland there is a fifth consideration: keeping the building below the height of existing boundary planting and away from the parkland edge removes any question of intrusion into views, which is worth doing whether or not an application is required.

Thinking about a project in Cockfosters?

Send the address and a short description. We will confirm the likely approval route and the drawings your project needs.

Book an Architectural ConsultationSee fixed-fee packagesor call 020 8054 8756

Local planning

Planning & conservation context

Class E permits buildings within the curtilage of a house for a purpose incidental to its enjoyment, subject to conditions: single storey, limits on eaves and overall height that vary with roof form and proximity to a boundary, no more than half the curtilage covered by buildings other than the original house, and nothing forward of the principal elevation.

On designated land the Class E allowance is more restricted — nothing to the side of the original house is permitted — so within the Trent Park conservation area the position must be checked before design.

A building used as habitable accommodation rather than for a purpose incidental to the enjoyment of the house falls outside Class E, and building regulations apply to a garden building depending on its size, use and proximity to a boundary.

Within the conservation area an outbuilding is assessed on its effect on the character of the area, so a simple form, a modest height and a position screened by existing planting are what make one acceptable.

On a plot near the park, a garden building sited away from the parkland edge and below the height of existing boundary planting removes any question of intrusion into views.

Replacing a poor existing structure with a better one is a positive element in an application rather than a neutral one.

Illustrative study — street elevation

Services

Architectural services in Cockfosters

Browse all London architectural services.

Nearby

Nearby Garage Conversion Architects pages

Garage Conversions in BarnetGarage Conversions in SouthgateGarage Conversions in Winchmore HillEnfieldWhetstoneTotteridge

Architecture in Cockfosters: FAQs

Can I convert the garage and still keep the storage?

On a plot with a decent garden, usually yes — and it is the move most people miss. The garage is the cheapest habitable space available because it is attached, on foundations and near services, while the functions occupying it are almost all incidental storage that does not need to be attached to the house at all. An outbuilding under Class E puts that storage back.

What does Class E allow?

Buildings within the curtilage of a house for a purpose incidental to its enjoyment — stores, workshops, garden rooms, home offices, gyms. Single storey, with height limits that vary with the roof form and are lower within two metres of a boundary, nothing forward of the principal elevation, and no more than half the curtilage covered by buildings other than the original house.

Can I sleep in a garden room?

Not under Class E. A building used as habitable accommodation — a self-contained annexe with sleeping and bathing facilities, or anything functioning as a separate dwelling — falls outside it. Working in a garden office is generally fine; regularly sleeping in one changes the character of the use, and building it on the assumption that it is a garden room is what leads to enforcement.

Does the conservation area change things?

Yes, in one important respect: on designated land nothing to the side of the original house is permitted development under Class E, which rules out the most convenient position on many plots and moves the building to the rear. Within the Trent Park conservation area the position should be checked before design rather than after.

Why do garden buildings end up with flat roofs?

Because any building within two metres of a boundary is limited to a lower overall height, and a dual-pitched roof is allowed more overall height than other forms. Put the two together and a building close to a fence usually needs a shallow or flat roof to stay within the allowance — which is a design constraint worth knowing before choosing a position.

What makes a garden room actually usable?

Insulation and airtightness, so it works year-round rather than for three months. Ventilation, which is the thing most often missing — a well-sealed small building with a person and a computer in it reaches uncomfortable humidity within hours. Services installed in one trench alongside the garage work. And a position that is neither a deterrent in February nor a greenhouse in July.

Do building regulations apply to an outbuilding?

It depends on its size, its use and how close it sits to a boundary. A small store may fall outside them; a workshop or office of any size, or a building close to a boundary, generally does not. Either way, the standards worth building to are those that make it usable — an uninsulated store gets condensation that ruins what is kept in it.

What does a garage conversion architect in Cockfosters charge?

We publish fixed-fee packages rather than quoting a percentage before seeing the house, beginning with a route review credited against the design work if you proceed. Where a garden building is part of the plan we design both together, because the services can be run once and the two buildings can be detailed to look like they belong to the same house.

How much does a garage conversion cost in Cockfosters?

Fees for garage conversions in Cockfosters follow scope, consent complexity and whether freeholder or specialist input is required. Published packages start from a fixed fee once scope is clear; council, engineer and freeholder surveyor fees are usually separate. See our packages page for current fixed-fee bands — we confirm a fee only after the address and proposed work are understood.

Discuss a garage conversion in Cockfosters

Send your Cockfosters address, photographs of the garage and the garden, and a note of what currently lives in the garage. We will test whether a Class E outbuilding can take it, check the conditions for your plot, and design the conversion and the garden building as one project.

Book an Architectural ConsultationEstimate the feesor call 020 8054 8756
Call 020 8054 8756Send Details