Extension plans and drawings across St Helens
We prepare extension plans and drawings for homes in St Helens, as a stand-alone service or as the first stage of a design and build project.
- Guide price in St HelensFrom £1,100 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsL34, L35, WA9, WA10, WA11
What is included
- 3D views to check the look and the light (full pack)
- Building regulations drawings and specification
- Measured survey of the house and garden
- Structural calculations from an engineer (full pack)
Local to St Helens
We cover St Helens and the postcode districts L34, L35, WA9, WA10, WA11, WA12. We also work in nearby Prescot (3 miles), Huyton (5 miles), Newton-le-Willows (5 miles), Golborne (6 miles).
The North West has a high share of Victorian and Edwardian terraces with rear yards and outriggers, plus large areas of inter-war semis in the suburbs.
What it costs in St Helens
Fees below are our St Helens guide (×0.95, the North West England factor), including VAT. Council and building control fees are extra.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Measured survey and planning drawings | £1,100 – £2,100 |
| Standard | Planning drawings plus building regulations drawings | £2,050 – £3,650 |
| Premium | Full pack with structural calculations and 3D visuals | £3,200 – £5,250 |
Try the guide-price tool to see a range for your own size and finish.
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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).
Our process, step by step
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
We visit your St Helens home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in St Helens
Who do I contract with in St Helens?
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.
How long does this take for a St Helens home?
2–6 weeks for drawings, depending on the council and the complexity of the project.
Do you cover all of St Helens?
Yes. We cover St Helens and the surrounding parts of Merseyside. Site visits are free and there is no obligation.
How much do extension plans cost?
Our design packs range from about £1,100 to £5,250 including VAT, from planning drawings only to a full pack with building regulations drawings, structural calculations and 3D views. Council fees are separate.
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.
Book a free site visit in St Helens
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.