A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
Thinking about a double-storey extension in Kilmarnock? We take charge of the whole project, co-ordinating every trade involved, and one person keeps you updated. Guide prices for Scotland sit at £58,000–£115,000 including VAT, and a typical job takes 14–22 weeks on site. Your own figure depends on what the survey finds and the specification you settle on.
- Guide price
- £58,000–£115,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- KA1
- Planning rules
- Scotland
- Local area
- East Ayrshire
- Survey
- Free, with a written quote
How much does a double-storey extension cost in Kilmarnock?
The table below shows guide prices for a double-storey extension in Kilmarnock. They are based on rates in Scotland, which run about 4% below the national guide, giving an overall range of £58,000–£115,000. All figures include VAT and are firmed up after a free site survey.
| Type of job | What it usually involves | Guide in Kilmarnock |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £38,500–£62,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £58,000–£115,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £96,000–£173,000 |
What moves the price up or down:
- How the new roof joins the existing roof
- Bathrooms, en-suites and plumbing on the upper floor
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What do you get?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Scaffolding for the full build, erected and inspected
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Local housing and a double-storey extension
Ayr, Kilmarnock and the coastal towns from Largs to Girvan have Victorian sandstone villas and terraces, with red sandstone common in older buildings. Former mining villages have rows of cottages, Irvine was developed as a new town from the 1960s, and harled post-war houses and newer estates are found across the area.
Sandstone homes need careful repointing and stone repairs, and harled houses commonly need re-rendering. Villas and semis suit extensions and loft conversions, and coastal homes often take window and roofline renewal.
Whatever era your Kilmarnock home dates from, we plan a double-storey extension around how it is actually built rather than a one-size-fits-all specification.
Do you need permission in Kilmarnock?
Which rules apply depends on where you live. For Kilmarnock, the answer is Scotland, and the points below reflect that; we verify them with the council before quoting.
In Scotland, extensions of more than one storey are only permitted development in narrow cases (Class 1B, well away from the boundary they face and outside conservation areas), so most need planning permission.
A building warrant is required before work starts. Scotland has no Party Wall Act; neighbour and title issues are handled under general law.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
Free site survey
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a double-storey extension, and photograph or measure anything the quote needs to reflect.
Quote in writing
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a double-storey extension.
Dates and permissions
We handle the paperwork side: checking whether planning permission or building control approval is needed, submitting applications where they are, and scheduling the trades and materials around your dates.
Build and hand over
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
Working with SK Home Improvements
Common questions
How much does a double-storey extension cost?
A typical double-storey extension of 30–40m² across both floors costs £58,000–£115,000, built to a plastered finish. As a rough guide, allow around £1,400–£2,600 per square metre plus fixed costs for groundworks, scaffolding and fees. The second storey usually costs less per square metre than the first, because foundations and roof are shared. Bathrooms upstairs and a complex roof add most. We confirm a fixed price after the survey.
Do I need planning permission for a two-storey extension?
Most two-storey extensions need planning permission, but it depends on the size, height and position, your home's location, whether it is listed or in a conservation area, and which UK nation you are in. In England, a two-storey rear extension can sometimes be built under permitted development if it is no deeper than 3m and at least 7m from the rear boundary. We check what applies before quoting.
Is the price fixed?
Yes, for the specification we agree. Your written quote sets out exactly what is included at a fixed price. It only changes if you ask for something different, or if a problem the survey could not reasonably reveal later needs extra work. In either case we explain the change and confirm it in writing before going ahead.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a double-storey extension, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
How is the new roof joined to the existing house?
The new roof is usually tied into the existing roof so the two read as one. On a rear extension this often means a lower ridge or a hipped end, with valleys where the slopes meet. We strip back some existing tiles, fix new rafters and battens, and lay matching tiles or slates. Lead or proprietary flashings seal the junctions so water runs off properly.
Near Kilmarnock
Addresses in KA1 are all covered for Kilmarnock, along with Irvine, Kilwinning and Ayr close by. Give us your postcode when you get in touch and we will confirm the details.