Two-storey annexe extensions in County Tyrone

County Tyrone at a glance

Nation: Northern Ireland
Price region: Northern Ireland
Postcode areas: BT
Towns covered: 8 listed below, plus surrounding villages
Approval route: Planning permission is needed: permitted development side extensions in Northern Ireland can't be more than 4 m high, which rules out two storeys.
Site visits: Free, no obligation

What a two-storey annexe extension involves

A two-storey annexe extension is an attached extension laid out as self-contained living space on two floors, usually with a living area and kitchenette below and a bedroom and shower room above, for a relative living with the family. It stays part of the main house rather than a separate home. Planning and council tax rules treat it differently from a separate dwelling.

Across County Tyrone we cover Omagh (BT78), Strabane (BT82), Dungannon (BT69), Cookstown (BT80), Coalisland (BT71) and Dromore (County Tyrone) (BT78), plus the smaller places around them.

Guide price in Northern Ireland

Using our Northern Ireland rates, a two-storey annexe extension with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £76,000–£101,500 (plus kitchenette and shower room fittings, priced to your choice), including VAT. Bigger or more glazed designs cost more per m². The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	Typical project
Essential	£1,660–£2,230 per m²	£69,500–£93,500
Standard	£1,800–£2,420 per m²	£76,000–£101,500
Premium	£2,160–£2,900 per m²	£91,000–£122,000

Rules in Northern Ireland

In Northern Ireland, a two-storey annexe at the rear can be permitted development within 3 m of the original rear wall and 7 m from the rear boundary, with the usual conditions. A side annexe needs a planning application costing £347, and councils may add conditions linking its use to the main house.

Approval in Northern Ireland: Planning application for works to a house: £347. Councils aim to decide local applications within an average of 15 weeks; many take longer.

Building control: Building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets.

There is no Party Wall Act in Northern Ireland. Shared walls and boundaries are a matter of title and common law, so we agree access and record conditions with neighbours before work starts.

Getting the design right

Annexe, not a separate house

To stay an annexe, the space should be used by members of the household and stay linked to the main house, usually with an internal door and shared address, garden and services. Designing it as a fully separate home can mean the council treats it as a new dwelling.

Fire separation and escape

A kitchenette in an annexe and a bedroom above need safe escape and suitable separation from the main house. Building control checks the escape windows, smoke alarms and the door between the two parts.

How we work in County Tyrone

Start at your house
We come to your home in County Tyrone, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering County Tyrone.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Towns we cover in County Tyrone

Two-storey annexe extensions in County Tyrone: questions

How much does a two-storey annexe extension cost in County Tyrone?

In Northern Ireland our guide is £1,800–£2,420 per m² including VAT, so about £76,000–£101,500 (plus kitchenette and shower room fittings, priced to your choice) for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Can I rent out an annexe later?

Not always. Many annexe permissions include a condition that it is only used by members of the household, so renting it out may need a fresh planning application. If you think you might want to let it, tell us at the start so we can explain the options.

Can an annexe have its own front door?

It can, but a separate front door, kitchen and address together make it look more like a separate home, which can change how the council treats it for planning. Many annexes have their own door to the garden or side and an internal door to the main house. We explain how each choice is likely to be viewed before the design is fixed.

Can an annexe be designed for someone with limited mobility?

Yes. We can plan a ground-floor bedroom space, a level-access shower, wider doorways, lever handles and space for a stairlift later. These features are much cheaper to build in at the start than to add afterwards, and they keep the annexe useful as needs change.

Will I need planning permission in County Tyrone?

County Tyrone is in Northern Ireland. Planning permission is needed: permitted development side extensions in Northern Ireland can't be more than 4 m high, which rules out two storeys.

Neighbouring areas

All extension services in County Tyrone · About two-storey annexe extensions