- Planning permission and Building Regulations are two separate systems.
- Exemption from planning does not mean exemption from Building Regulations.
- Almost every habitable attic conversion is subject to Building Regulations.
- Compliance is evidenced by a Certificate of Compliance on completion.
Two systems, two questions
Planning permission asks a single question: may this development take place at this location? Building Regulations ask a different question: given that it is taking place, how must it be built so that it is safe, healthy, energy-efficient and durable? Both questions have to be answered on almost every attic conversion.
Planning permission
Planning is administered by the local authority. It concerns land use, external appearance and impact on neighbours — the outside of the project. Certain works are formally exempted development under the Planning and Development Regulations, subject to conditions.
The 27 July 2026 update introduced new exemptions for certain side and rear dormer works, subject to conditions such as aggregate internal volume, design and position. Even where a project qualifies as exempt, it is still a good idea to have the assessment recorded in writing.
Building Regulations
Building Regulations are a technical standard for how buildings are constructed. They are grouped into Parts and cover, among other things:
- Part A — Structure
- Part B — Fire safety
- Part D — Materials and workmanship
- Part F — Ventilation
- Part G — Hygiene
- Part H — Drainage and waste water disposal
- Part K — Stairways, ladders, ramps and guards
- Part L — Conservation of fuel and energy
For attic conversions the most commonly relevant Parts are A, B, F, K and L. Compliance is not optional. Whether or not planning is required, the works must be designed and built to satisfy the applicable Parts.
Where the confusion comes from
Homeowners often hear that a project is “exempt” and take that as a green light for any construction. In reality the exemption is only from the requirement to make a planning application. All the technical requirements — structure, fire safety, stairs, insulation, ventilation — apply the same way as they would with a full application.
Documentation and sign-off
Building Regulations compliance is documented differently depending on the scope of the project. For most single-home attic conversions, a suitably qualified professional issues a Certificate of Compliance on completion. This is the paperwork a solicitor typically looks for at sale or refinance.
What this means for your project
Treat the two questions as separate from the very beginning. Answer the planning question first — is planning permission needed? — and then focus on the technical design that satisfies Building Regulations. A design that meets both cleanly is usually cheaper than one that has to be adjusted mid-build.
What this means for your project
Every home is different. Use this guidance to ask the right questions and to shape your brief — but confirm what applies to your specific property with a home survey and appropriate professional input.
Frequently asked questions
- If my attic conversion is exempt from planning, is that the end of the compliance question?
- No. Building Regulations still apply to the works. They cover structure, fire safety, ventilation, energy, drainage and more.
- Who signs off Building Regulations compliance?
- For most single-house works, a Certificate of Compliance is issued by a suitably qualified professional at the end of the project. The exact certification depends on the scope of works.
- Does the local authority check Building Regulations?
- Building Control has the power to inspect and to require rectification. On smaller works the certification chain is usually the professional's responsibility, but Building Control oversight remains in the background.
- What if a previous conversion was done without paperwork?
- It is a common situation. A retrospective assessment by a suitably qualified professional can identify what compliance work is needed. This often becomes relevant at sale or refinance.
Start with a quick check of your attic.
Answer a few simple questions about your home and what you would like to create. We’ll give you an early indication of which conversion route may be worth exploring. A home survey is still required before suitability can be confirmed.
Or call +353 85 150 0853