Helston, Cornwall
Glazed rear extension in Helston
Full-height glass, slim frames and big rooflights for the most open rear room. We design, get the approvals for and build glazed and glass-box rear extensions in Helston and the surrounding area, with one contract from the first survey to building control sign-off.
We cover Helston (TR13) as part of our Cornwall work. If your garden in Helston faces south, expect us to talk about overhangs and solar-control glass before frame colours.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a glazed rear extension cost in Helston?
In Helston, our guide for a glazed rear extension is £2,910–£4,990 per square metre including VAT for a standard specification. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £35,000–£60,000 |
| 4 m wide × 6 m deep (24 m²) | £70,000–£120,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a glazed rear extension in Helston?
Here is how the rules in England apply to a glazed rear extension in Helston.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Helston like to extend?
Stone-built and rendered houses are common around Helston, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
How a glazed rear extension in Helston comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Glazed rear extensions near Helston
From Helston, the nearest places we also cover are Camborne (7.7 miles) and Redruth (9.2 miles).
- Glazed rear extension in Camborne
- Glazed rear extension in Redruth
- Glazed rear extension in Falmouth
- Glazed rear extension in Penzance
- Glazed rear extension in Truro
Other work in Helston:
FAQ
Glazed rear extension questions in Helston
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Is a glass box a conservatory?
No. It is built to Building Regulations as part of the house, with insulated floor and roof, so it is usable all year.
Is the site visit in Helston free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How much does a glazed rear extension cost in Helston?
As a guide, £2,910–£4,990 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £35,000–£60,000 at that rate. Your written price follows the survey.
How long does a rear extension take to build in Helston?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.