Extensions over a garage in Gwynedd and Anglesey

Gwynedd and Anglesey at a glance

Nation: Wales
Price region: Wales
Postcode areas: LL
Towns covered: 10 listed below, plus surrounding villages
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.
Site visits: Free, no obligation

What an extension over a garage involves

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.

Gwynedd and Anglesey towns we list: Bangor (Gwynedd and Anglesey) (LL57), Holyhead (LL64), Caernarfon (LL54), Llangefni (LL60), Bethesda (LL57) and Pwllheli (LL51). Every other address in Gwynedd and Anglesey is covered as well.

Guide price in Wales

For budgeting in Gwynedd and Anglesey, allow around £29,000–£42,000 for an extension over a garage with 3 m × 6 m of new first-floor space (18 m²). That's based on £1,610–£2,350 per m² including VAT for Wales. These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.

Spec	Per m²	Typical project
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

Rules in Wales

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).

The Party Wall etc. Act 1996 applies in Wales, so notices may be needed for work on or near a shared wall or boundary.

Getting the design right

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.

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.

How we work in Gwynedd and Anglesey

Start at your house
We come to your home in Gwynedd and Anglesey, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Get it approved
Once you're happy with the design we submit it to the council for Gwynedd and Anglesey and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Towns we cover in Gwynedd and Anglesey

Extensions over a garage in Gwynedd and Anglesey: questions

How much does an extension over a garage cost in Gwynedd and Anglesey?

In Wales our guide is £1,610–£2,350 per m² including VAT, so about £29,000–£42,000 for 3 m × 6 m of new first-floor space (18 m²). Essential and Premium specs move that by roughly 8% down or 20% up.

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.

Do I need to convert the garage as well?

No. You can keep the garage for parking or storage and build only the room above, as long as the floor between them and any door into the house meet fire separation rules. Converting the garage at the same time is often good value, because the walls and foundations may be upgraded anyway.

Will I need planning permission in Gwynedd and Anglesey?

Gwynedd and Anglesey is in Wales. 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.

Neighbouring areas

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