Mid Glamorgan · Extensions & Renovations

Double-storey extensions in Porthcawl

Typical time on site: 14–22 weeks on site. Guide price in Porthcawl: £55,000–£110,000 including VAT.

Two-storey side extension on a brick semi-detached house

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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.

Porthcawl sits within our coverage for a double-storey extension, as do neighbouring Bridgend, Maesteg and Llantwit Major. Before giving a price we want to see the property: the condition of what's there now, the access, and anything that might need extra work. The guide range for Wales is £55,000–£110,000 including VAT, and your written quote will spell out exactly what that covers.

Guide price
£55,000–£110,000 inc VAT
Time on site
14–22 weeks on site
Postcodes
CF36
Planning rules
Wales
Local area
Bridgend
Survey
Free, with a written quote

What should you budget for a double-storey extension in Porthcawl?

What will a double-storey extension cost in Porthcawl? Our guide range is £55,000–£110,000 including VAT. That figure is adjusted for Wales, about 8% below the national guide, and is intended for planning a budget. A firm written price for your chosen specification follows a free survey at your home.

Type of jobWhat it usually involvesGuide in Porthcawl
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

Your price depends mostly on:

  • 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

What does the job include in Porthcawl?

  • 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
  • Windows, external doors, plastering and internal doors
Side two-storey extensionUses space beside a detached or semi-detached house for a wider plan.
Over-garage extensionBuilds a new room above an existing garage, checking the foundations first.
Hipped roofA roof that slopes on every side, matching many semi-detached and detached homes.
Gable roofA simpler pitched roof with a triangular end wall, usually quicker to build.

Building in Porthcawl

The Rhondda, Cynon and Merthyr valleys are lined with stone terraces built for mining families, stepped along steep hillsides. Pontypridd, Caerphilly and Merthyr Tydfil have Victorian centres, and Bridgend has grown with large modern estates alongside interwar and post-war housing.

Valley terraces commonly need repointing, roof repairs, rendering and window replacement, and loft conversions can add useful space. Newer estate homes often take garage conversions, porches and landscaping.

These patterns matter for a double-storey extension: older walls, roofs and floors in Porthcawl can need different materials or extra preparation compared with newer homes.

Do you need permission in Porthcawl?

Because Porthcawl falls under Wales's rules, the guidance below is the version relevant to you. Before sending a price, we check your property's position with the council.

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.

What happens after you get in touch?

  1. A visit to your home

    First, someone visits your home in Porthcawl 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.

  2. Written quote

    After the survey we send a quote for a double-storey extension that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.

  3. Dates and permissions

    Next comes planning the work itself. We set a start date that suits you, line up the right trades, and make sure any approvals for a double-storey extension are in place before the first day on site.

  4. On site to finish

    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.

Working with SK Home Improvements

One contract, several tradesJobs that need builders, plasterers, electricians and decorators come under a single contract, so you are not coordinating separate firms yourself.
Clear staged paymentsThe quote sets out when each payment falls due, linked to stages of the work, so you know in advance what is owed and when.
Certified where requiredElectrical, gas and other notifiable work is carried out by suitably registered people, and you receive the relevant certificates when it is finished.
Realistic timetablesWe give you an honest estimate of time on site at the quote stage and keep you informed if anything affects the programme once work starts.

Frequently asked questions

How long does a double-storey extension take?

A double-storey extension typically takes 14–22 weeks on site, depending on size, roof design and weather. Foundations and ground-floor walls come first, then the first-floor joists, upper walls and roof. Once it is weathertight, electrics, plumbing, plastering and finishes follow. Allow extra time beforehand for drawings, calculations and approvals. We give you a stage-by-stage programme with your quote.

Which postcodes in Porthcawl do you cover?

We cover CF36, along with the rest of Mid Glamorgan. 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.

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.

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.

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.

Nearby towns

Addresses in CF36 are all covered for Porthcawl, along with Bridgend, Maesteg and Llantwit Major close by. Give us your postcode when you get in touch and we will confirm the details.

Ready for a written price?

Want to know what a double-storey extension would cost for your house in Porthcawl? Our guide-price tool gives you a range, and a free survey turns it into a written quote.

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