In 2026, the construction cost of a typical new build detached house in Northern Ireland ranges between £2,000 and £2,800 per square metre depending on specification, complexity and site conditions. A 200m² house would therefore typically cost between £400,000 and £560,000 for construction alone, excluding land and professional fees.

Site Conditions – Sloping sites / Poor ground / Rural access / Drainage requirements

Specification Level – Basic finish / Mid range finish / High end bespoke

Construction Method – Blockwork / Timber frame / Hybrid systems

Energy Performance Level – Building regulation standards / Enhanced fabric first / Passivhaus standard

Architect and consultant fees
Planning application fees
Structural engineer
SAP or energy assessment
Building control fees
Ground investigation
Landscaping
Utility connections

Generally not at current material and labour costs unless specification is very basic and site conditions are simple.

Often yes, due to site works and service connections

Yes, it is possible to build a house in the countryside in Northern Ireland, but planning permission is required and strict policy criteria apply.

Most rural homes are assessed under Policy CTY 10, 11, or 12 of the Strategic Planning Policy Statement. Approval is generally based on demonstrating an active farming need, a replacement dwelling, infill opportunity, or redevelopment of an existing building.

Design, integration into the landscape, access, and impact on rural character are all carefully considered. Each application is assessed on its individual merits, so early site appraisal and professional advice are essential before progressing with a purchase or design.

Not always, overall specification and detailing matter more than structural system.

Initial consultation to sketch options: 2 to 4 weeks

Developed design to Planning: 4 to 8 weeks

Technical drawings for Building Control and construction: 4 to 8 weeks

So from first meeting to Planning submission can often take 6 to 12 weeks, depending on complexity and how quickly decisions are made.

Planning permission is not always required for a rear extension, as some projects fall within Permitted Development rights. However, this depends on the size, height, location, and whether your property has previous planning approvals or restrictions. It is always advisable to have this formally assessed before starting design or construction.

Permitted Development in Northern Ireland refers to a range of minor building works and alterations that can be carried out to a house without applying for full planning permission. These rights are set out within the Planning (General Permitted Development) Order (Northern Ireland) 2015. See link

For houses, this can include certain rear or side extensions, porch additions, rooflights, dormer windows, garage conversions, and outbuildings, provided they fall within defined limits relating to size, height, location, and overall impact.

A Certificate of Lawfulness in Northern Ireland is a formal legal document issued by the local Planning Authority which confirms that proposed or completed works are lawful in planning terms.

It is typically used where development falls within Permitted Development rights and does not require planning permission. The certificate provides written confirmation that the works comply with planning legislation, protecting you from future enforcement action and providing reassurance to lenders or future purchasers that the development was carried out legally.

No

Yes, however it would be at your own risk as Building Control may request information to be assessed that could delay the project or potential alter established work.  Always check with your council first.

A SAP assessment (Standard Assessment Procedure) is the method used to calculate the energy performance of a new build home and demonstrate compliance with Building Regulations.

It assesses the predicted energy use for heating, hot water, lighting, and ventilation based on the dwelling’s fabric performance, airtightness, heating system, and renewable technologies.  It is generally part of the Building Control application.

The assessment is carried out at design stage and again on completion. The results are used to produce the Energy Performance Certificate (EPC) and confirm that the home meets the required standards for energy efficiency and carbon emissions.

Building Regulations in Northern Ireland do not specifically require you to install solar panels or an air source heat pump in a new home.

However, Part F of the Building Regulations (Conservation of Fuel and Power) sets minimum targets for energy efficiency and carbon emissions. To meet these targets, most new homes now require low carbon technologies such as photovoltaic panels or heat pumps, particularly where fossil fuel heating systems are proposed.

These systems help reduce primary energy demand and CO2 emissions, allowing the dwelling to achieve the required SAP rating and overall compliance. In practice, renewable technologies are often the most cost effective way to meet the performance standards set by the regulations.

MVHR (Mechanical Ventilation with Heat Recovery) is a whole house ventilation system that continuously extracts stale air from wet rooms such as kitchens and bathrooms, while supplying fresh filtered air to living spaces and bedrooms.

As the air passes through the unit, heat from the outgoing stale air is transferred to the incoming fresh air. This improves indoor air quality while significantly reducing heat loss, making MVHR particularly effective in airtight homes.

Under Northern Ireland Building Regulations Part K (Ventilation), other compliant systems can also be used. These include intermittent extract fans, passive stack ventilation, and continuous mechanical extract ventilation (MEV). The appropriate system will depend on the airtightness level of the dwelling and the overall energy strategy.

Yes. You can design and build a genuinely low energy home without formal Passivhaus certification by applying fabric first principles, excellent airtightness, high insulation levels, careful thermal bridge detailing, and efficient ventilation.

However, Passivhaus certification brings clear benefits. It provides independent verification that the design and construction meet a proven performance standard. The rigorous modelling through PHPP, quality assurance checks, and on site testing reduce performance gaps and give clients confidence that the home will deliver predicted comfort and energy savings. Certification can also enhance resale value and demonstrates a measurable commitment to sustainability.

An air test, also known as an airtightness or blower door test, measures how much uncontrolled air leaks in and out of a new build home through gaps in the building fabric.

A calibrated fan is temporarily fitted into an external door to pressurise and depressurise the house. The equipment then measures the rate of air leakage, typically expressed as air changes per hour.

It is important because excessive air leakage leads to heat loss, higher energy bills, draughts, and reduced comfort. Achieving a good airtightness result helps the insulation and ventilation systems perform as intended, improves energy efficiency, and is required to demonstrate compliance with Building Regulations.

Building Regulations maximum allowable air permeability:

Northern Ireland         10m3/(h.m2) – TB Part F1 2022

Republic or Ireland     5m3/(h.m2) – TGD Part L 2019)

Scotland                        5m3/(h.m2) – Section 6

England & Wales        8m3/(h.m2) – Approved Document L

Passivhaus                 0.6m3/(h.m2)