Conservatory replacement extensions in St Helens: design, approvals and build
Our design and build teams take on conservatory replacements in St Helens, from the first measured survey through planning and building control to the finished room.
- Guide price in St HelensFrom £19,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–14 weeks on site
- Postcode districtsL34, L35, WA9, WA10, WA11
Planning and approvals in St Helens
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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).
Is a conservatory replacement right for your house?
- Conservatories that are too hot or too cold
- Older uPVC conservatories near the end of their life
- Homes where the conservatory sits unused
Local to St Helens
Our survey diary covers St Helens, including L34, L35, WA9, WA10, WA11, WA12. The same team covers Prescot (3 miles), Huyton (5 miles), Newton-le-Willows (5 miles), Golborne (6 miles), all within easy reach.
Just over the Greater Manchester border, Ashton-in-Makerfield is about 4 miles away. 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.
Conservatory replacement prices in St Helens
Prices below are for St Helens, using the North West England factor of ×0.95. They are guide ranges including VAT for the build only, not a quote.
Typical rates in St Helens: £1,760 to £3,320 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 3.3 m 10 m² | £19,000 – £23,000 | £20,000 – £26,500 | £26,000 – £33,500 |
| 3.5 m × 4 m 14 m² | £24,500 – £29,500 | £28,500 – £37,000 | £36,500 – £47,000 |
| 4 m × 5 m 20 m² | £35,000 – £42,000 | £40,500 – £52,500 | £52,000 – £66,500 |
Includes removal of the old conservatory. Reusing existing foundations is only possible after investigation.
For a figure based on your own dimensions, use our guide-price tool.
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in St Helens
How long does a conservatory replacement take to build in St Helens?
On site, typically 8 to 14 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Will my neighbours in St Helens 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.
Do I need building regulations approval in St Helens?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Does replacing a conservatory need planning permission?
A solid replacement is treated as a new extension, so it must meet the permitted development limits or get planning permission, and it always needs building regulations approval.
Is it worth replacing a conservatory with an extension?
If the conservatory is unusable for much of the year, usually yes. A solid extension gives a heated room that counts as proper living space. Our guide range is about £1,760 to £3,320 per m² including VAT, including removal.
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.