Single Storey Extension Drawings
Single Storey
Extension Plans.
Plans for single storey extensions across London and the South East. Our rear extension package includes a measured survey with 3D scanning and an online design meeting.
Drawings are typically ready 5–10 working days after the survey and brief are confirmed. Rear extension plans from £600.
The short answer
What Drawings Does a Single Storey Extension Need?
A typical planning package for a single storey extension includes existing and proposed floor plans, elevations, relevant sections and site and location information. Together they show the house as it is, the new extension and how it sits next to the neighbouring properties.
Many homeowners start from estate agent plans, but these are not accurate enough. Small differences change the design. We record the building, visible boundary features, levels and relevant neighbouring details, including any previous extensions. Any uncertainty over the legal boundary must be resolved separately. The planning route also depends on the property type, its location, its planning history and any local restrictions.
- We start with how you want to use the extra space: a kitchen extension, more living space, a utility room or a home office.
- We consider depth, roof form and glazing to help maintain daylight in the existing rooms.
- We check the planning history of the house and the street first. That way the drawings answer the council’s likely questions.
From approval to construction
Single Storey Extension Plans Made Clear
When you are planning a single storey extension, we survey and draw the existing property first. Then we develop the proposed plans, elevations and sections. Good drawings let the council, your neighbours and, later, your builder understand the design without guesswork.
The drawing shown is from our approved scheme at 54A Church Road in Richmond, a rear and side extension at lower ground floor level. The elevation shows the extension’s depth and roof line in relation to the existing house and the ground floor windows above it.
Prepared properly
Led by MCIAT-qualified professionals
Our drawing work is led by Chartered Architectural Technologists.
A clear programme
Typically 5–10 working days
We confirm the drawing programme once the survey and your brief are complete.
Ready for the next stage
Technical work coordinated in-house
Building regulation drawings, structural engineering and Party Wall work can follow under a separately agreed scope.
Your drawing package
What’s Included in Your Single Storey Extension Plans?
A drawing package prepared for your property. Preparing drawings suitable for an application is part of the package; submitting the application and handling council correspondence are confirmed separately in your quotation.
Measured Site Survey
We record the building, visible boundary features, ground levels and the neighbouring details we can see from your property, giving every drawing an accurate base.
Existing Plans & Elevations
Floor plans and elevations of the house as it stands, including earlier extensions that may affect your allowance.
Design Development
We test depth, height, roof form and glazing against the house and the neighbours before fixing the layout.
Proposed Floor Plans
The proposed layout, openings into existing rooms and connections between the new and existing spaces.
Elevations & Sections
The extension’s height, eaves level near the boundary, roof falls and rooflights.
Application-Ready Drawing Set
A coordinated PDF set prepared for the agreed planning route.
What it costs
How Much Do Single Storey Extension Plans Cost?
Prices cover the drawing package shown on each card. Council fees, specialist reports, building regulation drawings and structural calculations are not included. The overall project budget depends mainly on the extension’s size, glazing, structure, ground conditions and specification. The depth bands describe the size of scheme, not whether it qualifies for a particular planning route; that depends on your property and the complete proposal.
Rear extension packages
Drawings for a straightforward rear extension start from £600 and include a site visit with 3D scanning and an online design meeting.
Side, wraparound and complex projects
Side and rear schemes start from £1,000 and wraparound extensions from £1,300. Extensions to flats and constrained sites are quoted once we have seen the property.
Larger Rear Extension, 6–8m
Survey, plans and elevations for a deeper rear extension where the neighbour consultation scheme may apply.
Side and Rear Extension
Survey, plans and elevations for a combined scheme, prepared for the route that suits the proposal.
Wraparound Extension
A full drawing set for a wraparound single storey extension. Extensions to flats are quoted individually.
Council fees are paid separately. From 1 April 2026 the national fee in England is £548 for a householder application and £249 for prior approval of a larger home extension. A proposed Lawful Development Certificate costs half the relevant planning fee.
We confirm the scope, planning route and fixed quotation before you appoint us.
Real project evidence
A Single Storey Extension Plan Is Not a Template.
A neat set of plans can still miss the reason a council might refuse. The value lies in knowing what the drawings need to demonstrate for that particular site.
The brief. At 54A Church Road in Richmond, a family wanted to turn a dark two-bedroom lower ground floor flat into a three-bedroom home with open-plan living. The site. The property is in the St Matthias Conservation Area, with an Article 4 Direction, a Tree Preservation Order and flood risk recorded as site constraints.
The Design Response
The guidance was the starting point. The proposed extension is 7.5m deep, well beyond the 3.5m depth the council’s guidance treats as comfortable. Because the property is a flat, householder permitted development did not apply, so the scheme had to be justified as a planning application.
We showed that the extension sits at lower ground floor level, with its eaves under 2.2m. It also continues a building line the council had approved before, under 22/2346/FUL and 23/2434/FUL. A daylight and sunlight assessment, an arboricultural impact assessment and a flood risk assessment supported the application.
Coordinating the Next Stage
Later stages were considered during design. Three decisions were made before planning was granted:
- Escape route: the bedroom was arranged to open onto the hallway rather than rely on an escape window, subject to Building Control confirmation.
- Structure: load-bearing walls are being removed, so the steel, foundations and retaining detail were updated when the layout changed.
- Party Wall: notice was served on the adjoining owner and an award was agreed without dispute.
Planning permission was granted by the London Borough of Richmond upon Thames on 29 June 2026 under PA26/1090, with no objections from the neighbours consulted. The project is at pre-construction stage.
CLIENT FEEDBACK
Loved by homeowners and builders.Trusted across every detail.
“Great experience working with them. Professional, responsive, and technically thorough throughout the project. The structural advice and drawings were clear and delivered promptly. Would definitely recommend their services.”
“Excellent service! Very professional and punctual . Competitive price.”
“We used AC Design Solution for planning permission on a single storey extension and loft conversion, plus the building regulation drawings, structural calculations, and party wall surveying. They handled the whole process well and kept us updated throughout, which made things a lot less stressful than we expected. The drawings and structural work were solid, and the party wall side went smoothly too. Would recommend them to anyone needing help with planning and building regs.”
“I had an issue on site that required appointing a Party Wall Surveyor. My architect recommended Zubear from AC Design Solution, who I must say is extremely experienced and kept me updated throughout. We faced a challenging experience with the council and their surveyor, but Zubear overcame the issues, allowing me to get my Party Wall matters sorted out.”
Your project
Single Storey Extension Types We Design
Single Storey Rear Extensions
Often used to turn an existing small kitchen at the rear of the property into a kitchen diner with views of the garden. The drawings show how far it will extend beyond the rear wall, its height near the boundary and the new opening into the existing rooms.
We draw the extension as part of the whole house rather than as a separate box.
Side Return Extensions
On Victorian and Edwardian terraces, a side return extension fills the narrow passage beside the back addition. Side return extension plans need to resolve the roof junction, the boundary wall and the light reaching the middle of the house.
The drawings must show how the new roof meets the existing outrigger and the neighbour’s wall.
Wraparound Extensions
A wraparound combines a single storey side extension and a rear extension in an L shape.
Because it changes two sides of the house, its size, roof and effect on the neighbours need careful drawing. The planning route must be checked for the whole scheme.
Lower Ground Floor and Flat Extensions
Extensions to flats need planning permission, as householder permitted development does not apply. Building at lower ground floor level brings retaining walls, drainage and escape routes into the design. Any extra depth must be justified on the site’s merits.
Glazing and Rooflights
Deep extensions can leave the middle of the house dark. Rooflights, a glazed strip next to the house and wide doors help bring natural light back in.
Large south- or west-facing glazing also needs shading and ventilation thought through at design stage, so the room does not overheat in summer.
Built around real projects
Relevant project evidence.
54A Church Road, Richmond — Rear and Side Extension
Lower ground floor extension to a flat in a conservation area.
Akenside Road, Hampstead
Single storey rear extension where we rebuilt the drawings and foundation design after work had started.
Do You Need Planning Permission for a Single Storey Extension?
It depends on the property and the full proposal. The routes below apply in England. Every figure is subject to the limits and conditions that apply to your property.
Permitted Development and Lawful Development Certificates
Under permitted development rights, many houses can extend up to 3m beyond the rear wall of the original house. For a detached house, the limit is 4m. This needs no planning application. Height, eaves near the boundary, materials and the area of land covered are also limited. Different limits apply to extensions of more than one storey.
A proposed Lawful Development Certificate gives formal confirmation from the local planning authority that the work would be lawful. It is optional, but often useful when you come to sell. You can read the planning rules on the Planning Portal or check with your local planning authority.
Prior Approval for a Larger Home Extension
A deeper rear extension, up to 6m or 8m for a detached house, can go through prior approval. The council then consults the neighbours. This route is not available in conservation areas.
Work may start once the council confirms approval is not needed or is granted. If it makes no decision, work may start 42 days after it received the complete notification.
Householder Planning Application
You need one if the extension goes beyond permitted development. You also need one if a planning condition or Article 4 Direction has removed your rights, or a combined side and rear scheme does not meet the rules. If you live in a conservation area, side extensions are not permitted development, though some rear extensions still are.
Councils usually aim to decide within 8 weeks of the application being validated. If the house is listed, listed building consent is usually needed as well, and it is separate from planning permission.
Full Planning Application for Flats
Extensions to flats and maisonettes need a full planning application, because householder permitted development does not apply to them.
Supporting reports such as a daylight assessment, heritage statement or flood risk assessment may be required, depending on the site and the council’s validation list.
Planning Drawings Are Not Construction Drawings
Each stage answers a different question. Planning drawings do not automatically become construction drawings, and extension builders cannot build from them alone.
Planning Drawings
Planning drawings show what the extension will look like, where it sits and how it relates to the house and the neighbours.
They deal with size, height, appearance and planning impact. Our house extension drawings service covers other extension types.
Building Regulation Drawings
Most extensions need building regulations approval, whether or not planning permission is needed. Building regulation drawings for a single storey extension set out the construction, insulation, drainage, ventilation and fire safety.
Building Control checks the building work and issues a completion certificate when it is satisfied.
Structure and Party Wall Matters.
Structural Calculations
A new opening into the house usually needs a beam, and the extension needs foundations suited to the ground. A structural engineer for house extensions sizes these from calculations for your project.
At Akenside Road in Hampstead, we arranged trial pits after taking over the project, then designed the footings around what they found.
Party Wall Matters
Building on or near a shared boundary, or digging foundations close to a neighbour’s building, may be notifiable under the Party Wall etc. Act 1996. Where it is, notice must be served before the work starts.
A neighbour may consent; if not, surveyors agree an award. Our Party Wall surveyor service, led by Zubear Ali, can advise whether your project is affected.
Why Use a Chartered Architectural Technologist?
Extension plans do not have to be prepared by a registered architect. What matters is an accurate survey, sound design judgement and drawings the council can assess without guessing.
AC Design Solution is led by MCIAT-qualified Chartered Architectural Technologists, with structural engineering and Party Wall surveying available in-house.
That matters because an extension project is rarely separate from the rest of the house. A wider opening needs a beam. A wall on the boundary may need a Party Wall notice. A roof that works for planning can create a difficult junction later.
These services are priced separately from the planning drawings. Having them in one practice means decisions are made with the next stage in mind.
The value is not in drawing software. It is in recording the right information, asking the right questions and designing around the real property.
Common questions
Single Storey Extension Plans: FAQs
Which Planning Route Will My Extension Need?
The route depends on your property, location, planning history and proposed design. Some rear extensions to houses qualify as permitted development; larger proposals may qualify for prior approval. Other schemes need a householder or full planning application. We assess the appropriate route before preparing your drawings.
What Drawings Will I Receive?
Typically existing and proposed floor plans, elevations, relevant sections and site information. The exact set depends on the type of extension and the planning route.
Is the Measured Survey Included?
Yes, a site visit with 3D scanning is included in our rear extension packages. We do not use estate agent plans in place of a survey.
How Long Do the Plans Take?
Typically 5–10 working days once the survey and your brief are confirmed. Council decision times are separate.
Are Submission and Council Fees Included?
Council fees are paid separately. Application preparation, submission and council correspondence are included only where expressly stated in your quotation.
How Many Revisions Are Included?
Your quotation sets out the number of design revisions included and how any additional changes are charged.
Does the 45-Degree Rule Apply to Single Storey Extensions?
Many councils use it as a guide to the effect on a neighbour’s nearest window. It is a planning guideline, not law, and a daylight and sunlight assessment can give firmer evidence where needed.
Can My Builder Build From Planning Drawings?
No. Before building a single storey extension, builders need building regulation drawings and, usually, structural calculations.
Can Planning Approval Be Guaranteed?
No. We design around the planning issues and prepare clear drawings, but the decision rests with the council.
Do I Need Building Regulations Approval if Planning Isn’t Needed?
Usually yes. Planning and building regulations are separate, and most extensions need approval from Building Control.
Can an Additional Storey Be Added Later?
Possibly. It will usually need planning permission, and the foundations must carry the extra load. Tell us at the start if you might build up later.
Tell us what you are planning
Request a fixed quote for your single storey extension.
Send us the property address, photographs, any existing plans and a short description of the extension you have in mind.
Continue your research
Extension Advice and Guidance.
Previous Owner Built Without Permission: What Should the New Homeowner Do?
Discovering building work that does not appear to have the right approvals can turn what looked like a straightforward renovation into a much more complicated project.
Renovating a Home in a Camden Conservation Area
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Can You Extend the Front of Your House?
Front extensions usually need planning permission. Learn the rules, permitted development limits, building regulations, costs, and design considerations before you build.