What is a glazed extension?
A glazed or contemporary extension uses large panes of glass, slim aluminium frames and modern cladding to create a bright room that contrasts with the original house. Frameless corners, structural glass roofs and minimal sliding doors are typical features.
How much does a glazed extension cost in Helensburgh?
In Helensburgh, a glazed extension typically costs £2,700–£4,050 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £48,500–£73,000. Prices in Scotland sit near the national average for this kind of work, and the range for Helensburgh reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £35,000–£52,500 |
| Typical project (18 m²) | £48,500–£73,000 |
| Larger project (25 m²) | £67,500–£101,000 |
| Rate per m² | £2,700–£4,050 |
The biggest cost drivers are:
- Steel framing
- Cladding material
- Overheating and energy design
- Glazing size, specification and lead time
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a glazed extension in Helensburgh?
Approvals for a glazed extension in Helensburgh follow the rules for Scotland. In Scotland a single-storey extension is often permitted development (Class 1A): where any part is within 1 metre of a boundary, it can project up to 3 metres from the rear wall of a terraced house or 4 metres on other houses, with eaves no higher than 3 metres, an overall height of 4 metres and no more than half the front or rear garden covered. The rights do not apply in conservation areas or to flats, and a building warrant will usually still be needed before work starts.
In Scotland a building warrant is needed before work starts on most extensions, loft conversions and conversions. It is issued by the council’s building standards service. When the work is finished, a completion certificate is submitted and accepted by the council after inspection.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most glazed extensions:
- Structural design for steel frames and glass supports
- Large-format sliding doors and fixed glazing
- Contemporary design and planning drawings
- Energy and overheating calculations where needed
- Building control sign-off
- Foundations, walls and insulated roof
How long does it take?
The build itself usually takes 12 to 16 weeks on site; glazing lead times can be 6 to 10 weeks. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Helensburgh
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Our Helensburgh coverage includes postcode districts G84, and we also work in nearby places such as Greenock, Dumbarton and Dunoon.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about glazed extensions in Helensburgh
Who approves a glazed extension in Helensburgh?
Planning matters in Helensburgh go to the council covering your address, and the work needs a building warrant. We prepare and submit the applications for you.
Will a glass extension be too hot in summer?
It can be if poorly designed. Solar-control glass, roof overhangs and opening vents reduce overheating, and building regulations may require calculations to show the design works.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
How much does a glazed extension cost in Helensburgh?
In Helensburgh, a glazed extension typically costs £2,700–£4,050 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £48,500–£73,000. Your fixed price depends on the survey and drawings.
Do I need planning permission for a glazed extension in Helensburgh?
In Scotland a single-storey extension is often permitted development (Class 1A): where any part is within 1 metre of a boundary, it can project up to 3 metres from the rear wall of a terraced house or 4 metres on other houses, with eaves no higher than 3 metres, an overall height of 4 metres and no more than half the front or rear garden covered. The rights do not apply in conservation areas or to flats, and a building warrant will usually still be needed before work starts.
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.