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Extensions over a garage in Magherafelt

From the first sketch to final sign-off, we plan and build over-garage extensions in Magherafelt and the surrounding County Londonderry area.

  • Guide price in MagherafeltFrom £20,500 inc VAT
  • PlanningPermission from the council needed
  • Build time12–18 weeks on site
  • Postcode districtsBT45
Detached house with a bedroom extension above the attached garage

Will the council need to approve it?

In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.

In a conservation area or area of townscape character the permitted development rights are more limited, listed homes need listed building consent, and if rights have been removed by a condition, any extension needs an application.

Building close to a public sewer needs the agreement of NI Water, which we check during design.

Northern Ireland has no Party Wall Act. Where work is on or close to a shared boundary, we agree access and protection with your neighbour in writing before work starts.

Applications are decided by your council, which handles local planning in Northern Ireland.

How much does an over-garage extension cost in Magherafelt?

Labour and material costs vary across the UK, so for Magherafelt we use our Northern Ireland factor (×0.86). The ranges include VAT and exclude design, structural and council fees.

Typical rates in Magherafelt: £1,550 to £2,920 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
Over a single garage
12 m²
£20,500 – £25,500£21,500 – £28,000£27,500 – £35,500
Over a large single garage
16 m²
£24,500 – £30,500£28,500 – £37,500£37,000 – £47,000
Over a double garage
24 m²
£37,000 – £45,500£43,000 – £56,000£55,500 – £70,500

Try the guide-price tool to see a range for your own size and finish.

Is an over-garage extension right for your house?

  • Homes where the landing can connect to the new room
  • Detached and link-detached houses with an attached garage
  • Families needing a bedroom without losing garden

Fitting the new room to the existing landing is the planning puzzle inside the house. We design the connection first, then the roof, so the extension does not end up with awkward steps or a corridor through a bedroom.

Covering Magherafelt

Our survey diary covers Magherafelt, including BT45. Nearby, we also take on projects in Limavady (23 miles), Coleraine (26 miles), Derry/Londonderry (31 miles).

Cookstown, in County Tyrone, is roughly 9 miles from Magherafelt and also on our list. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.

How the project works

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.

  2. Design and approvals

    We produce the drawings and structural design, and manage the approvals so they are in place before work starts.

  3. Fixed written price

    You receive a written, itemised price and programme. Nothing starts until you are happy with it.

  4. Build and sign-off

    Work is carried out to the agreed programme, inspected by building control and signed off at the end.

Common questions in Magherafelt

Do you cover all of Magherafelt?

Yes. We cover Magherafelt and the surrounding parts of County Londonderry. Site visits are free and there is no obligation.

How long does an over-garage extension take to build in Magherafelt?

On site, typically 12 to 18 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.

Can I see a price before committing to anything?

Yes. The guide prices on this page are adjusted for Magherafelt, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.

Can I keep using the garage during the build?

Usually not for parking. The garage roof is removed and the space below is used for access and props for part of the build.

Can my garage take the weight of a room on top?

Some can and some cannot. Many garages have a single-skin wall or shallow foundations. Our structural engineer checks this before we give a fixed price.

Book a free site visit in Magherafelt

We will measure up, check the planning position and give you honest guide figures.

  • Free, no-obligation site visit
  • Planning route checked before you spend on drawings
  • Written price once the design is agreed
  • Building control sign-off at the end

Prefer to talk? Call 0800 088 6341 or .

Book a free site visit

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