Extension plans and drawings across Windsor
Need extension plans and drawings in Windsor? We survey the house, prepare what the council needs and deal with the officers until a decision is made.
- Guide price in WindsorFrom £1,300 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsSL1, SL3, SL4
Design and approval fees for Windsor
These are guide fees for Windsor, adjusted for South East England (×1.12) and including VAT. Council application and inspection fees are paid separately.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Measured survey and planning drawings | £1,300 – £2,500 |
| Standard | Planning drawings plus building regulations drawings | £2,450 – £4,300 |
| Premium | Full pack with structural calculations and 3D visuals | £3,800 – £6,200 |
Want a range for your exact size? The guide-price tool takes about a minute.
Covering Windsor
Our survey diary covers Windsor, including SL1, SL3, SL4. Neighbouring towns we cover include Slough (2 miles), Maidenhead (6 miles), Bracknell (8 miles), Wokingham (11 miles).
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
What is included
- 3D views to check the look and the light (full pack)
- Structural calculations from an engineer (full pack)
- Planning drawings: existing and proposed plans and elevations, site and location plans
- Two or three layout options to compare
- Building regulations drawings and specification
- Measured survey of the house and garden
Do I need planning permission in Windsor?
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
The planning position for a specific Windsor address depends on its history and any designations, which is why we check it at the first visit.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions answered
Who do I contract with in Windsor?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will my neighbours in Windsor be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How long does this take for a Windsor home?
2–6 weeks for drawings, depending on the council and the complexity of the project.
Do I need an architect?
Not necessarily. For most extensions an experienced designer or architectural technologist is enough. For listed buildings or complex sites an architect’s input can help.
Can I use your drawings with another builder?
Yes. Once paid for, the drawings are yours to use for your project.
Book a free site visit in Windsor
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.