Llantwit Major · Cardiff and the Vale of Glamorgan

Extensions over a garage in Llantwit Major

For an extension over a garage in Llantwit Major, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Cardiff and the Vale of Glamorgan.

Before you start in Llantwit Major, here's what applies.

Postcode districts
CF61 and CF71
County / area
Cardiff and the Vale of Glamorgan, Wales
Price region
Wales
Guide price
£29,000–£42,000 (£1,610–£2,350 per m²)
Approval route
Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission.
Nearest towns
Rhoose (5.9 miles), Bridgend (7.6 miles), Pencoed (7.8 miles)
Distance to Cardiff
about 14 miles
First visit
Free, no obligation

About an extension over a garage

An extension over a garage suits you if you have an attached single garage beside the house and need an extra bedroom or a larger main bedroom with an en-suite. You get an inspection of the garage structure, a design that matches the house, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.

Around Llantwit Major we also work in Rhoose, Bridgend and Pencoed, and across the rest of Cardiff and the Vale of Glamorgan. Postcode districts in and near Llantwit Major: CF61 and CF71.

What it costs in Llantwit Major

Our guide for Wales is £1,610–£2,350 per m² including VAT. On a project with 3 m × 6 m of new first-floor space (18 m²), that puts an extension over a garage in Llantwit Major at roughly £29,000–£42,000. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

SpecPer m²3 m × 6 m of new first-floor space (18 m²)
Essential£1,480–£2,160 per m²£26,500–£39,000
Standard£1,610–£2,350 per m²£29,000–£42,000
Premium£1,930–£2,820 per m²£35,000–£50,500

Planning and building regulations in Llantwit Major

In Wales, building over a side garage can be permitted development if the result is at least 10.5 m from the boundary opposite the side wall, set back at least 1 m from the front of the house and does not widen the house by more than 50%. Garages close to the boundary usually fail these tests, so a householder application costing £585 is often needed.

Approval in Wales: Householder planning application: £585. Councils normally decide householder applications within 8 weeks.

Building regulations: Building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency).

Design points for Llantwit Major homes

Fire separation

If the garage stays a garage, the floor between it and the room above, and any door into the house, must give fire separation under building regulations. That usually means fire-resisting plasterboard ceilings, sealed gaps and a fire door, which we design in from the start.

Checking the garage foundations

Garages are often built on shallow strip footings sized for a single-storey wall and a light roof. A trial hole shows their depth and condition, and the engineer decides whether they can carry two storeys or need underpinning or new foundations inside the garage.

How we'd run your project

  1. Understand the brief

    At your home in Llantwit Major we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.

  2. Design and approvals

    We draw the extension and check it against the rules for Wales, then apply for planning permission or a certificate of lawfulness, whichever fits.

  3. Engineer it

    Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.

  4. Build and hand over

    We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about extensions over a garage in Llantwit Major

How much does an extension over a garage cost in Llantwit Major?

Our guide for Wales, which covers Llantwit Major, is £1,610–£2,350 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £29,000–£42,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Llantwit Major?

We cover Llantwit Major (CF61 and CF71) and nearby places including Rhoose, Bridgend and Pencoed, plus the rest of Cardiff and the Vale of Glamorgan. The first site visit is free.

How long does an extension over a garage take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils normally decide householder applications within 8 weeks), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

Can my garage take a room on top?

Sometimes, but it needs checking. Many garages are built on shallow footings with thin walls, designed only for a single storey. We dig a trial hole and inspect the walls, and the structural engineer decides whether to reuse them, strengthen them, underpin the footings or build new foundations inside the garage.

How do I get into a room over the garage?

Usually through a new opening off the existing landing or a bedroom, so the stairs stay where they are. If the floor levels do not match, a step or two may be needed inside the new room. Where a landing opening is not practical, a new stair from a converted garage is an option.

Nearby

Close to Llantwit Major? We work across the area, including:

Other extensions in Llantwit Major

All two-storey extension services in Llantwit Major · Extensions over a garage across Cardiff and the Vale of Glamorgan

Tell us about your house in Llantwit Major and we'll call you back to arrange a free, no-obligation visit.

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