Flat roof extensions across Dunoon
We take on flat roof extensions in Dunoon by arrangement. Because of travel and logistics, we agree the programme and any travel costs in writing before the survey.
- Guide price in DunoonFrom £20,500 inc VAT
- PlanningScottish householder rules; building warrant needed
- Build time10–16 weeks on site
- Postcode districtsPA23

Extensions in and around Dunoon
We cover Dunoon and the postcode districts PA23. Island and remote projects are planned individually, with travel, deliveries and accommodation for the team agreed before the survey.
Across Scotland, extensions follow Scottish planning and building standards, including the building warrant process, which we build into the programme from the start.
Do I need planning permission in Dunoon?
In Scotland, householder permitted development rules (Class 1A for single-storey ground-floor extensions and Class 1B for extensions of more than one storey) allow some smaller extensions without a planning application, within limits on depth, height and distance from the boundary. Conservation areas and listed buildings are more restricted.
The planning position for a specific Dunoon address depends on its history and any designations, which is why we check it at the first visit.
Scotland has no Party Wall Act. Where work affects a shared wall or a neighbour's land, we agree access, protection and making good with your neighbour in writing before work starts.
In Scotland a building warrant from the council is needed before work starts on almost any extension, and a completion certificate is issued when the work is accepted. Building standards are set in the Scottish technical handbooks.
Applications are decided by your council as planning authority.
How much does a flat roof extension cost in Dunoon?
Prices below are for Dunoon, using the Scotland factor of ×0.98. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Dunoon: £1,720 to £3,280 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £20,500 – £24,500 | £24,000 – £31,000 | £30,500 – £39,500 |
| 4 m × 5 m 20 m² | £34,000 – £40,500 | £40,000 – £51,000 | £50,500 – £66,000 |
| 5 m × 6 m 30 m² | £51,000 – £60,500 | £60,000 – £76,500 | £76,000 – £98,500 |
For a figure based on your own dimensions, use our guide-price tool.
When a flat roof extension makes sense
- Extensions under first-floor windows where a pitch will not fit
- Homeowners who want maximum light from above
- Modern and 1930s onwards houses
Height is often what decides a flat roof. Under first-floor windows, a pitched roof may not fit at all; a flat roof keeps the extension low while still giving a good ceiling height inside.
From first visit to completion
Visits to Dunoon are arranged around travel; we confirm any travel costs in writing before the survey.
Site visit by arrangement
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about a flat roof extension in Dunoon
How long does a flat roof extension take to build in Dunoon?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Do I need building regulations approval in Dunoon?
Yes. Almost every extension needs it, whatever the planning route. In Scotland that means a building warrant before work starts.
Do you cover all of Dunoon?
Yes. We cover Dunoon and the surrounding parts of Argyll and Bute. Projects here are taken on by arrangement because of travel, and any travel costs are agreed before the survey.
Can I walk on a flat roof extension?
Only for maintenance unless it is designed as a terrace. A roof terrace or balcony needs planning permission and a different structure.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,720 to £3,280 per m² including VAT.
Talk to us about a project in Dunoon
We will talk through the project, the planning position and how we would organise the visit and the build.
- Site visit arranged around travel, costs agreed first
- 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 .
Send us your project details
Tell us a little about the project and we will arrange a time.