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.
Clwyd is part of our UK-wide coverage for a double-storey extension. Places we cover include Wrexham, Buckley, Deeside and Colwyn Bay, and we travel to smaller communities across the area as well. Since your property is in Wales, the relevant planning and building rules are the ones set there. In Wales, budget around £55,000–£110,000 with VAT; the figure is confirmed after a survey that costs you nothing.
- Guide price
- £55,000–£110,000 inc VAT
- Time on site
- 14–22 weeks on site
- Planning rules
- Wales
- Price level
- About 8% below the national guide
- Towns listed
- 10
- Survey
- Free, with a written quote
How much does a double-storey extension cost in Clwyd?
No two jobs cost exactly the same, but the ranges below give a fair picture of a double-storey extension in Clwyd. Pricing for Wales runs about 8% below the national guide, and the overall guide is £55,000–£110,000 with VAT included. We'll confirm your figure after surveying the property for free.
| Type of job | What it usually involves | Guide in Clwyd |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £37,000–£60,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £55,000–£110,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £92,000–£166,000 |
The main things that change the figure:
- 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’s included?
- 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
- Roof structure tied into the existing roof, tiled to match
- Electrics, plumbing and heating by qualified trades, with certificates
- Building control inspections and completion certificate
Housing across Clwyd
Wrexham has Victorian terraces in red Ruabon brick, alongside interwar and post-war estates. The north coast resorts of Rhyl, Prestatyn and Colwyn Bay have Victorian villas, guest-house terraces and bungalows, while Denbighshire and Flintshire villages use local stone under Welsh slate roofs.
Terraces suit loft conversions and rear extensions, and many need repointing and roof work. Coastal bungalows commonly take loft rooms and window renewal, and stone cottages need lime-based repairs.
The north Wales coast is exposed to wind and salt from the Irish Sea, and the Clwydian hills inland are wetter and colder.
Do you need permission in Clwyd?
Planning law differs across the UK. For a home in Clwyd, it is the Wales rules below that count, and we check them with the council ahead of any quote.
In Wales, two-storey extensions are tightly limited under permitted development, including distance to the rear boundary, so most need planning permission.
Building Regulations approval is needed in Wales, and the Party Wall etc. Act 1996 applies to work on or near shared walls.
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
We look at the job
First, someone visits your home in Clwyd 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.
Price and scope agreed
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
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 job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
How we work
Frequently asked questions
Which postcodes in Clwyd do you cover?
We cover LL11, CH7, CH5 and LL28, along with the rest of Clwyd. If your postcode is not listed, get in touch anyway: our coverage is UK-wide, and we can usually arrange a survey wherever you live. Enter your postcode in the guide-price tool or contact form and we will confirm.
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.
Can we live at home while it is built?
Most families stay at home during a double-storey extension. The new structure is built outside first, and we only break through into the existing rooms near the end, usually one floor at a time. Upstairs, this may mean a bedroom is out of use for a week or two. We fit dust screens, protect floors and stairs, and plan any time without water or power in advance.
Do you cover Wrexham, Buckley and Deeside?
Yes. As well as Clwyd, we cover Wrexham, Buckley and Deeside and the rest of Clwyd. 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.
How much does a double-storey extension cost?
A typical double-storey extension of 30–40m² across both floors costs £55,000–£110,000, 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.
Towns in Clwyd
Find your town below. Every place listed in Clwyd is covered for a double-storey extension, with the same survey, written quote and fixed-price process.