Extension plans and drawings in Chalfont St Peter
Need extension plans and drawings in Chalfont St Peter? We survey the house, prepare what the council needs and deal with the officers until a decision is made.
- Guide price in Chalfont St PeterFrom £1,300 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsSL9
Covering Chalfont St Peter
Our survey diary covers Chalfont St Peter, including SL9. Nearby, we also take on projects in Gerrards Cross (2 miles), Amersham (5 miles), Chesham (7 miles), High Wycombe (8 miles).
For homes towards Hertfordshire, Rickmansworth is around 4 miles away. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Included in a typical project
- 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
- Building regulations drawings and specification
- Two or three layout options to compare
Will the council need to approve it?
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Fees in Chalfont St Peter
Guide fees for Chalfont St Peter including VAT, using our South East England factor of ×1.12. Council and building control charges are not included.
| 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.
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chalfont St Peter, 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 Chalfont St Peter?
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 Chalfont St Peter?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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.
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.
Book a free site visit in Chalfont St Peter
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.