Services / House extensions
House extensions
Drawings for every kind of house extension, from a kitchen side return to a double-storey rear extension, priced before we start.
- FreeInitial consultationA conversation about your project, and a first view of what's possible, before any fee is agreed.
- FixedFee for each stageEvery stage is priced in writing before it starts. No hourly billing.
- 3DSee the design firstYour design is shown in 3D before it's submitted, while changes are still easy.
- FreeResubmissionIf planning is refused, we revise and resubmit at no extra design fee. Conditions
What we draw
Single-storey rear
More kitchen and living space across the back of the house. Often permitted development, so a lawful development certificate may be all you need.
Side return and wrap-around
Filling the side passage of a terrace or semi, alone or wrapped around the back, for a wide open-plan kitchen.
Double-storey
A bigger bedroom or an extra one upstairs, with more ground-floor space below. Usually needs planning permission.
Front porch
A small porch or front extension, often permitted development within size limits.
Garage conversions
Turning a garage into a room, often permitted development, with the insulation and fire details building control asks for.
Conservatories and garden rooms
Conservatories, outbuildings and garden rooms, checked against permitted development limits first.
Raised patios and terraces
Terraces and steps to the garden, which need planning permission above a certain height.
Planning drawings
What's included
Extensions, loft conversions, porches and outbuildings that need planning permission or a lawful development certificate.
- Free initial consultation
- Measured survey of your home
- Existing plans and elevations
- Proposed design in 3D, with up to two rounds of changes
- Application prepared, submitted and managed to a decision
- Free resubmission if refused (conditions apply)
Before you start
What we need, and what sits outside our fee
- From you: the property address, a few photos, and any existing drawings, planning approvals or surveys you have. We arrange the measured survey with you.
- Not in our fee: council planning and building control fees, and specialist reports a council asks for, such as a tree survey or flood risk assessment, unless your fee proposal lists them.
- Your fee proposal sets out exactly what is included for your project before any work starts.
- Want it built too? Green Code Developers, the group's construction company, can build it under a separate contract, with one project lead throughout. How design and build works.
Timescales
How long it takes
We give you a timetable for our drawings in your fee proposal. Council and building control timings are the statutory or target periods and start once an application is validated.
- Planning decision (householder application)
- Target of 8 weeks after validation
- Lawful development certificate
- Councils aim to decide within 8 weeks
- Larger home extension prior approval
- 42 days, including 21 days for neighbours to comment
- Building regulations full plans
- 5 weeks, or up to 2 months if you agree
- Party wall notices
- 1 or 2 months' notice, depending on the work
Projects
House extensions we have designed
Common questions
Do I need planning permission for my extension?
Many single-storey rear extensions are permitted development, within limits on depth, height and materials. Houses in conservation areas, flats and maisonettes, and larger or double-storey extensions normally need permission. We check your house before you commit, and recommend a lawful development certificate where permitted development applies, so you have proof for a future buyer.
How long does the planning stage take?
Councils aim to decide householder applications within eight weeks of validation. We prepare and submit the drawings, answer the planning officer's questions, and keep you updated until the decision.
Will I need structural calculations?
Almost always for an extension: new openings, steel beams and foundations need to be designed for building control. Our complete package includes them.
Other services
- Free planning check
- Loft conversions
- Upward extensions
- Renovations and internal alterations
- Basement conversions
- Planning permission
- Lawful development certificates
- Pre-application advice
- Building regulations drawings
- Building control applications
- Structural calculations
- Structural surveys and letters of comfort
- Flat conversions
- Lease plans and licence to alter
- Change of use
- New builds
- Interior design
- 3D visualisation
- Energy and retrofit
- Energy Performance Certificates (EPC)
- Accessible home adaptations
- Commercial fit-outs and shopfronts
- Design consultations
- Party wall surveys
- Build over agreements and drainage
- Planning reports and statements
- Amendments, conditions and regularisation
- Planning appeals
- Conservation areas and listed buildings
- Community Infrastructure Levy (CIL)
- HMO planning and licensing
- Feasibility and site checks
- Measured surveys
- Building surveys
- Drawing reviews and second opinions
- Location and block plans
- Tender and construction support
- Principal designer (CDM and building regulations)
- Cost management
- Project management
- Contract administration
- Design and build
- Turnkey projects
- Landscape design
Where we work
House extensions across London
Local planning points for the boroughs closest to our Cricklewood studio: Ealing, Harrow, Brent, Hillingdon, Hounslow, Haringey, Enfield, Barnet, Camden, Westminster, Hammersmith and Fulham, Kensington and Chelsea. See all 33 boroughs.