Extension plans and drawings in High Wycombe
For High Wycombe homeowners we handle extension plans and drawings, with fees agreed in writing before any work starts.
- Guide price in High WycombeFrom £1,300 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsHP10, HP11, HP12, HP13, HP14
Fees in High Wycombe
Fees below are our High Wycombe guide (×1.12, the South East England factor), including VAT. Council and building control fees are extra.
| 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 |
For a figure based on your own dimensions, use our guide-price tool.
Working in High Wycombe
We cover High Wycombe and the postcode districts HP10, HP11, HP12, HP13, HP14, HP15. Neighbouring towns we cover include Marlow (4 miles), Amersham (6 miles), Chesham (8 miles), Chalfont St Peter (8 miles).
Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
Do I need planning permission in High Wycombe?
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 High Wycombe address depends on its history and any designations, which is why we check it at the first visit.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
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).
Who this service is for
- Projects that need a planning application or other approval
- Anyone who wants fixed designs before getting build prices
- Homeowners at the very start of a project
The most expensive changes are the ones made after the steel is ordered. A good design stage settles layout, heights, glazing and services on paper, so the build price is firm.
How the project works
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in High Wycombe
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for High Wycombe, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with in High Wycombe?
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.
Do I need building regulations approval in High Wycombe?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How much do extension plans cost?
Our design packs range from about £1,300 to £6,200 including VAT, from planning drawings only to a full pack with building regulations drawings, structural calculations and 3D views. Council fees are separate.
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 High Wycombe
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.