Two-storey extension plans and drawings in County Londonderry

County Londonderry at a glance

Nation: Northern Ireland
Price region: Northern Ireland
Postcode areas: BT
Towns covered: 11 listed below, plus surrounding villages
Site visits: Free, no obligation

What a set of extension plans involves

Two-storey extension plans involve a measured survey of your house, design options, and a set of scaled drawings showing the existing and proposed floor plans, elevations, a site plan and a location plan. These are the drawings needed for a planning application or certificate of lawfulness. Building regulations drawings with construction details follow as a separate, more technical set.

Across County Londonderry we cover Derry (BT48), Coleraine (BT51), Limavady (BT49), Magherafelt (BT45), Portstewart (BT55) and Portrush (BT56), plus the smaller places around them.

Fees

Planning drawings (survey and design) are a guide of £2,000–£3,500 and building regulations drawings and specification £1,500–£4,000, with your design stage priced in writing before it starts.

Rules in Northern Ireland

In Northern Ireland, the plans support a planning application to the local council, costing £347 per dwelling, or show that a rear extension meets the 3 m and 7 m permitted development limits. Building control drawings to the Building Regulations (Northern Ireland) and Technical Booklets follow.

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

Planning drawings versus building regulations drawings

Planning drawings show what the extension looks like and how it affects neighbours. Building regulations drawings show how it is built: foundations, structure, insulation, fire safety, ventilation and drainage. Most two-storey extensions need both, prepared at different stages.

Drawings that can be built

Drawings that ignore steel sizes, floor depths or drain runs often need redesigning once a builder prices them. We coordinate the design with the structural engineer and our build teams, so what is approved is practical to construct.

How we work in County Londonderry

Understand the brief
At your home in County Londonderry we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Get it approved
Once you're happy with the design we submit it to the council for County Londonderry and deal with any questions from the planning officer.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Towns we cover in County Londonderry

Two-storey extension plans and drawings in County Londonderry: questions

Do the plans include structural calculations?

Not at planning stage. Structural calculations and beam design are prepared by a structural engineer once the design is agreed, and they form part of the building regulations package. We coordinate the engineer's work with the drawings so steel sizes and floor depths match.

Do I own the plans once they are drawn?

You receive copies of the drawings to use for your project, including your planning application and building regulations approval. Copyright in drawings normally stays with whoever prepares them unless agreed otherwise. Your written design stage price sets out how the drawings can be used.

How long do extension plans take to prepare?

Survey, design and planning drawings usually take 4 to 8 weeks, depending on how many options you want to explore. Technical design, structural calculations and building control approval take a further 4 to 8 weeks, and this can overlap with the planning decision period.

Neighbouring areas

All extension services in County Londonderry · About two-storey extension plans and drawings