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.
Across Renfrewshire and Inverclyde, people look into a double-storey extension to replace something worn out, to make the house work better for them, or to get it ready for a sale. We cover Paisley, Greenock, Newton Mearns and Renfrew and the smaller towns around them, working to the rules that apply in Scotland. Expect a guide of £58,000–£115,000, VAT included, in Scotland, and every quote follows a free visit.
- Guide price
- £58,000–£115,000 inc VAT
- Time on site
- 14–22 weeks on site
- Planning rules
- Scotland
- Price level
- About 4% below the national guide
- Towns listed
- 7
- Survey
- Free, with a written quote
Double-storey extensions prices in Renfrewshire and Inverclyde
Use the table to gauge the cost of a double-storey extension in Renfrewshire and Inverclyde before we visit. Figures include VAT and are scaled for Scotland, coming out about 4% below the national guide, which gives £58,000–£115,000 overall. After a free survey, you receive a fixed written price.
| Type of job | What it usually involves | Guide in Renfrewshire and Inverclyde |
|---|---|---|
| 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 |
The main things that change the figure:
- Combined floor area across both storeys
- How the new roof joins the existing roof
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
Scope of the work
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Roof structure tied into the existing roof, tiled to match
- Scaffolding for the full build, erected and inspected
- Electrics, plumbing and heating by qualified trades, with certificates
- Building control inspections and completion certificate
Homes in Renfrewshire and Inverclyde
Paisley has sandstone tenements and terraces from its textile era, Greenock and Port Glasgow have tenements and housing climbing the hills above the Clyde, and Gourock and Kilmacolm have Victorian villas. Post-war estates and newer private housing surround the towns, and roughcast is a common finish.
Roughcast and tenement buildings commonly need re-rendering, window replacement and roof work. Villas suit kitchen extensions and landscaping, and semis often take loft conversions and driveways.
Inverclyde is one of the wettest parts of lowland Scotland, and homes facing the Firth of Clyde take wind and driving rain.
Planning and building rules in Renfrewshire and Inverclyde
Which rules apply depends on where you live. For Renfrewshire and Inverclyde, 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.
From survey to handover
Survey and measure
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Your fixed price
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Plan and prepare
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Build and hand over
Work goes ahead as scheduled and you deal with one contact throughout. When the last trade leaves, we clear and clean the site, talk you through what has been done and pass on any certificates and care instructions.
How we work
Questions about a double-storey extension in Renfrewshire and Inverclyde
Can you combine a double-storey extension with other work?
Yes. Because we manage several trades under one contract, we can plan a double-storey extension alongside other work on your Renfrewshire and Inverclyde home, such as new windows with rendering, or a kitchen refit with an extension. Combining jobs can reduce repeat set-up such as scaffolding, skips and access, and every element is listed and priced in the same 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.
Will the extension affect my neighbours?
A double-storey extension can affect neighbours' light, outlook and privacy, which is why planning departments look closely at height, depth and window positions. Side windows facing neighbours often need obscure glass. Work near a shared wall may also need party wall notices; the Party Wall etc. Act 1996 applies in England and Wales only. We talk through these points early so the design is realistic.
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.
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.
Towns in Renfrewshire and Inverclyde
Choose your town from the list to see how we price and plan a double-storey extension in your part of Renfrewshire and Inverclyde, including typical time on site.