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House Extension Drawings & Extension Plans
Single storey, double storey and wrap-around extension drawings prepared for UK local councils and building control. Permitted development guidance included, fixed fee from £1,800, delivered in two weeks with no site visit.
Every Common Extension, Drawn to Council Standard
An extension is the most direct way to add genuine living space to a UK home, and the drawings behind it determine whether the project runs smoothly or stalls at validation. We prepare scaled extension plans for every common residential arrangement, with new work clearly distinguished from the existing building.
Whether you are opening up the back of a terrace for a kitchen-diner or adding a full second storey over an existing garage, the drawing set needs to satisfy both the planning case officer and, later, the building control inspector. We produce both, and can supply the structural design alongside.
Single Storey Rear Extensions
The most common project we draw. Kitchen-diner extensions with bi-fold or patio doors, roof lights and a flat or pitched roof.
Double Storey Extensions
Adds a bedroom above the new ground floor space. Requires closer attention to foundations, existing structure and the impact on neighbouring light.
Wrap-Around Extensions
Combines a rear and side infill in one L-shaped footprint — the largest gain in floor area, and usually a full planning application.
Side Infill Extensions
Fills the dead space down the side return of a terraced or semi-detached house. Transformative on Victorian terraces.
Orangeries & Garden Rooms
Glazed and part-glazed structures, including the Part L glazing area considerations these bring.
Garage Conversions & Over-Garage
Converting an integral garage to habitable space, or building a new storey over it.
Does Your Extension Need Planning Permission?
A great many single storey rear extensions fall within permitted development rights and require no planning application at all. The standard depth allowance is 3 metres for an attached house and 4 metres for a detached house, with a maximum height of 4 metres and eaves no higher than 3 metres within 2 metres of a boundary.
Larger single storey rear extensions — up to 6 metres attached or 8 metres detached — can be built under the prior approval process, where the council notifies your neighbours and considers any objections on amenity grounds. Double storey extensions have tighter limits again, and permitted development rights are removed entirely in conservation areas, on listed buildings and where an Article 4 direction applies. We will tell you which route your project takes before you commit.
- check3m / 4m depth — standard single storey rear extension limit — attached / detached houses
- check6m / 8m depth — larger extensions available via the prior approval neighbour consultation process
- check4m maximum height — for a single storey rear extension, with 3m eaves within 2m of a boundary
- check50% curtilage rule — extensions must not cover more than half the land around the original house
- checkSide extensions — single storey only, maximum half the width of the original house
- checkConservation areas — permitted development rights are restricted or removed — check before designing
Planning Drawings, Structural Design and Building Regs
Most extensions need more than planning drawings. Once consent is in place, building control needs a technical set showing the construction build-up, the structural members and how the new work meets current regulations — which is why the majority of our extension clients take the Full Package.
That gives you the planning drawing set, the structural calculations for any beams or removed load-bearing walls, and the building regulations drawings including a cut section through the extension detailing foundations, cavity wall build-up, insulation and drainage falls.
- checkExisting & proposed plans — scaled floor plans of every affected level
- checkAll affected elevations — front, side and rear, with new work distinguished from retained fabric
- checkSite & location plans — 1:1250 and 1:500 with the red-line application boundary
- checkConstruction section — foundation, cavity wall, insulation and roof build-up fully annotated
- checkStructural calculations — beam sizing, padstones and bearing details for any structural opening
- checkDrainage layout — new waste runs, gradients and inspection chamber connection to Part H
Fixed Fees, and a Two-Week Delivery Promise
A traditional architect will typically quote £3,000 to £5,000 for an extension drawing package and take ten weeks or more, with site visits billed on top. Because we work entirely online and specialise in residential planning and building regulations work, we deliver the same standard for £1,800 to £2,700 in two weeks.
Our fees are fixed and confirmed before you commit. Revisions are included as standard — we would rather get the design right than charge you each time you want to move a wall on paper.
Extension Drawings — From £1,800
Planning drawings are £1,800. Most extensions also require structural design and building regulations drawings, so the Full Package at £2,700 is the usual choice — planning, structural and building regs combined, cheaper than booking each separately.
House Extensions — Frequently Asked Questions
Do I need planning permission for a rear extension?
Many single storey rear extensions fall within permitted development. The standard depth limit is 3 metres for an attached house and 4 metres for a detached house, with a maximum height of 4 metres. Larger extensions up to 6 or 8 metres are possible through the prior approval process. Permitted development rights are removed in conservation areas and where an Article 4 direction applies.
How much do house extension drawings cost?
Planning drawings are a fixed £1,800. Most extensions also need structural calculations and building regulations drawings, so the majority of clients take the Full Package at £2,700, which combines all three and costs less than booking each separately.
What is the difference between planning drawings and building regulations drawings?
Planning drawings show what the extension will look like and how it sits on the site — they are what the council assesses for planning permission. Building regulations drawings are the technical set showing how it will actually be built: foundations, wall build-up, insulation, structural members and drainage. Most projects need both.
How long do extension drawings take?
Two weeks from receiving your measurements and photographs, guaranteed for standard projects. Larger or more complex proposals may take slightly longer, and we will tell you upfront if that applies to yours.
Do you provide the structural calculations for the extension too?
Yes. Where you are removing a load-bearing wall to open into the new space, or need beams over openings, we prepare the calculations and annotate the member sizes onto the drawings. This is included in the Full Package or available separately at £650.
What is a wrap-around extension?
A wrap-around extension combines a rear extension with a side return infill in a single L-shaped footprint. It delivers the largest gain in ground floor area and is particularly effective on Victorian terraces, though it generally requires a full planning application rather than falling under permitted development.
Can you draw a double storey extension?
Yes. Double storey extensions need closer attention to the existing foundations, the structural connection to the original house and the impact on neighbouring light, but we prepare them regularly for both planning and building control.
Do you need to visit my property?
No. We work entirely online across the UK. We send you a measuring kit with a laser measurer and a clear guide showing which dimensions and photographs we need, and prepare the drawings from what you send back. This method underpins our 98% first-time approval rate.
Ready to Get Started?
Tell us about your project and we'll come back within 24 hours with a fixed price and a confirmed two-week delivery slot. No site visit required — we work remotely right across the UK.
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