Modular does not mean exempt
Irish Building Regulations apply to the design and construction of new buildings, including dwellings, unless a specific exemption applies. The regulations set minimum performance requirements across Parts A to M.
The Department of Housing also states that compliance responsibility rests with the owner and the builders and designers engaged. A factory warranty or supplier promise does not transfer that statutory responsibility away from the project team.
What Parts A–M mean for a dwelling
| Area | Buyer-level question | Typical evidence to request |
|---|---|---|
| Part A — Structure | Can the building, connections and foundation resist the site loads? | Site-specific calculations, drawings and foundation reactions |
| Part B — Fire | How are escape, alarms, linings, structure and separation addressed? | Fire design drawings, specifications and product classifications |
| Part C — Site/moisture | How are radon, ground moisture, rain and condensation controlled? | Ground, membrane, junction and condensation-risk details |
| Part D — Materials/workmanship | Are products suitable, traceable and installed correctly? | Product data, DoPs, certification and installation instructions |
| Part E — Sound | Does the design limit internal and external sound transmission? | Build-ups, junction details and relevant test/calculation evidence |
| Part F — Ventilation | Will fresh air and moisture extraction work after airtightness measures? | Ventilation design, commissioning and user information |
| Part G/H — Hygiene/drainage | Are water, sanitary facilities, drainage and wastewater coordinated? | Plumbing, drainage and site-services design |
| Part J — Heat appliances | Are heat-producing appliances and flues safely designed? | Appliance, flue, ventilation and commissioning records |
| Part K/M — Safety/access | Are stairs, guarding, entrances, rooms and sanitary facilities usable? | Dimensioned access and safety drawings |
| Part L — Energy | Does the complete dwelling meet energy and carbon requirements? | DEAP assessment, thermal details, systems design and BER route |
Technical Guidance Documents show common ways of demonstrating compliance, but a design may use another approach if adequately demonstrated. That is a professional design decision, not a marketing shortcut.
CE marking, DoPs and Agrément are different
CE marking and DoP
For construction products covered by the applicable European framework, the manufacturer declares performance against relevant characteristics. This gives designers data; it does not approve the whole dwelling.
NSAI Agrément
Agrément certification can assess innovative systems or products for stated conditions and uses. Check the certificate scope, limitations, installation requirements and whether the exact proposed system is covered.
The Building Control route
Building Regulations describe performance. Building Control Regulations set procedures for demonstrating and recording compliance. The exact route depends on the work and circumstances.
- Appoint competent Irish designers early enough to review the system before ordering.
- Agree the Building Control strategy, including the Commencement Notice and whether statutory certification or an available opt-out route is appropriate.
- Define the owner, builder, designer, design certifier and assigned-certifier roles where applicable.
- Coordinate factory inspections with site inspections and retain traceability for concealed work.
- Lodge completion documentation required for the route before the dwelling is occupied or used.
A new single dwelling may have an opt-out option from statutory certification in qualifying circumstances, but the Department makes clear that opting out does not remove the need to comply with Building Regulations or Building Control procedures.
Documents to demand before a deposit
Minimum due-diligence pack
- Dimensioned architectural, structural and services drawings.
- Complete wall, roof and floor build-ups with named products.
- Structural calculations and foundation loads for Irish review.
- Fire, energy, ventilation, moisture and accessibility design information.
- Declarations of Performance and certificates with matching product/system names.
- Installation, lifting, transport and weather-protection method statements.
- Factory quality-control and inspection records available to the Irish certifier.
- A responsibility matrix covering factory, delivery, foundation, module joins and services.
- Written list of exclusions and the documents supplied at completion.
Have the Irish project professionals review this material. A large PDF bundle is not useful if it describes a different model, climate, configuration or regulatory jurisdiction.
Six supplier red flags
“CE means approved”
It does not certify the completed building against all Irish requirements.
No Irish design contact
Nobody is identified to answer the architect, engineer or certifier.
Generic calculations
The documents do not reflect the proposed openings, foundation or site exposure.
Undefined interfaces
The factory and groundworker each assume the other owns the critical junction.
Certificates after payment
Evidence is promised only after the deposit or delivery.
No completion pack
The contract does not define as-built drawings, commissioning and inspection records.
Frequently asked questions
Can a cabin under 45m² ignore Building Regulations?
No general rule says that a dwelling below 45m² is exempt from Building Regulations. Class 3A concerns planning exemption and expressly preserves relevant Building Regulations and Building Control obligations.
Can an Irish engineer certify an imported home after arrival?
A professional can only certify within their competence and based on adequate design and inspection evidence. Concealed factory work and undocumented changes can make late certification difficult or impossible.
Does a foreign building approval work in Ireland?
It may provide useful evidence, but it does not automatically demonstrate compliance with Irish requirements. NSAI notes that third-country certifications do not by themselves meet EU and Irish requirements.
Is BER the same as Building Regulations compliance?
No. BER records energy performance. The project must also address structure, fire, moisture, ventilation, drainage, access and other relevant requirements.
Official sources
Legally and technically reviewed: 6 August 2026. General educational information, not a compliance determination or professional certification. Appoint competent designers for the exact system and site.