A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
We offer a single-storey extension across Ayrshire, and Kilmarnock is one of the places we cover, along with nearby Irvine, Kilwinning and Ayr. Before anything is agreed we visit, check the existing structure and talk through your options. You then receive a written quote setting out the full scope; for most homes in Scotland it sits within £33,500–£72,000 including VAT.
- Guide price
- £33,500–£72,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- KA1
- Planning rules
- Scotland
- Local area
- East Ayrshire
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Kilmarnock?
To help you plan, we show what a single-storey extension typically costs in Kilmarnock instead of holding figures back for a sales call. The range is £33,500–£72,000 with VAT, using rates in Scotland that are about 4% below the national guide. A free survey then fixes your actual price.
| Type of job | What it usually involves | Guide in Kilmarnock |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £21,000–£38,500 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £33,500–£72,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £67,000–£125,000 |
Expect these to shape the final quote:
- Floor area, shape and number of corners
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
Scope of the work
- Groundworks, foundations and below-ground drainage
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Building control inspections and completion certificate
Building in Kilmarnock
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.
The Firth of Clyde coast is exposed to westerly winds, salt and frequent rain, which affects render, roofs and window seals.
That mix of housing shapes how we approach a single-storey extension in Kilmarnock: the age and construction of your home affect the materials, the method and, in the end, the price.
Do you need permission in Kilmarnock?
As Kilmarnock is in Scotland, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
In Scotland, Class 1A permitted development covers some single-storey extensions, within limits on depth, height and distance from boundaries, and not in conservation areas or on flats. Anything outside those limits needs planning permission from the council.
A building warrant from the council’s building standards service is usually needed before work starts, and a completion certificate is accepted at the end. There is no Party Wall Act in Scotland; work near a boundary is agreed with neighbours under general law.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
The four stages
A visit to your home
First, someone visits your home in Kilmarnock to see the space, take measurements and note anything that could affect the work, such as access or the condition of what is there. There is no charge for this visit.
Your fixed price
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Dates and permissions
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
Build and hand over
During the work we protect the areas around it and tidy up at the end of each day. Once complete, we check the finish, remove our materials and hand over paperwork such as building control sign-off where it applies.
Why homeowners choose us
Common questions
Is a flat roof or a pitched roof better on an extension?
A flat roof is quicker to build and usually costs less, gives a clean modern look and works well with a roof lantern. A pitched roof matches the main house, sheds water faster and allows a vaulted ceiling, but it costs more and its height can affect neighbours. Modern flat roofs in EPDM rubber or GRP last well when properly detailed. Planning rules on height can also decide the choice.
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
How much will a single-storey extension cost in Kilmarnock?
As a guide, expect to pay £33,500–£72,000 including VAT for a single-storey extension in Kilmarnock. That range is adjusted for Scotland, which runs about 4% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Do you cover Irvine, Kilwinning and Ayr?
Yes. As well as Kilmarnock, we cover Irvine, Kilwinning and Ayr and the rest of Ayrshire. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Near Kilmarnock
Our coverage in Kilmarnock includes KA1. We also travel to Irvine, Kilwinning and Ayr, so neighbouring addresses are looked after on exactly the same terms as those in town.