Free house extension plans, from your own floor plan
Upload the estate agent's floor plan or a sketch of your idea, and Extension Plans builds the house in 3D and draws everything you need to talk to the council: scaled floor plans, elevations, roof plans, A3 planning sheets, a planning statement and Building Regulations sections.
Start your extension plans — freeHow it works
- Upload your floor plan. A PDF or a picture: an estate agent plan, a survey, or your own mock-up with the new walls drawn in a colour. Pages headed "Ground floor" and "First floor" go on the right floors by themselves.
- The house is built for you. The site reads the walls, works out the existing house and each extension (one colour per extension), which parts are two storeys, where the windows are, and puts on roofs.
- Set the true scale. Click both ends of one wall you have measured and type its length. The whole house resizes to match.
- Check it and tweak it. Drag walls, change heights and roofs (gable, hip, lean-to or flat), add doors, windows and bi-folds, and look at every side in the Elevations and 3D views.
- Print the paperwork. A3 planning sheets with title blocks and scale bars, a planning statement, a permitted development check, and Building Regulations sections and specification — all as PDFs.
What you get
| Planning application | Location plan sheet (for your Ordnance Survey plan), block plan with boundary distances, existing and proposed floor plans, all four elevations, roof plans — A3, at 1:50, 1:100, 1:200 or 1:500 as needed. |
|---|---|
| Planning statement | Written from your drawings: the proposal, design, materials, neighbours and parking, with a materials table. Edit it, then print it or download it as a Word file. |
| Permitted development check | Each extension checked against the Class A rules for houses in England, with the reasons, and a list of what to send the council. |
| Building regulations | 1:50 sections through each extension, annotated plans, insulation sized to pass Part L, U-value table, and a specification covering foundations to fire alarms, radon, ventilation and drainage. |
| 3D model | Walk round the house before and after, with brick and slate, to check the proportions. |
Questions
Is Extension Plans free?
Yes. There is no account and nothing to pay. The site is paid for by adverts.
Can I submit the drawings to the council?
They are a guide only. They are laid out the way councils expect, but they must be checked and approved by a qualified professional, such as an architect or architectural technologist, before you submit them. Building Control will also need a structural engineer's calculations.
Do I need planning permission for my extension?
Many single-storey rear extensions are permitted development, but side extensions over one storey, front extensions and two-storey rear extensions close to the boundary usually need planning permission. See the permitted development guide; the site checks your design for you.
What drawings do I need for a householder planning application?
See the planning drawings checklist: a location plan, block plan, existing and proposed plans and elevations, and roof plans where the roof changes.
Does it work in Scotland, Wales or Northern Ireland?
The drawings work anywhere, but the permitted development check and Building Regulations specification follow the rules for England only.
Are my plans uploaded anywhere?
No. Your plans are read and traced in your own browser and stay on your device. See the privacy policy.