Mobile homes in gardens: what Class 3A excludes

Class 3A does not provide an exemption for a temporary caravan or mobile home. Condition 5 specifically excludes temporary construction, giving those examples. A permanent garden dwelling needs its own assessment against every condition; a supplier’s description alone does not settle the planning position. Read S.I. No. 340/2026, Class 3A, condition 5.

What does condition 5 mean for your proposal?

Start with the actual structure and intended use. Ask the supplier for drawings, a construction specification and a written description of the accommodation. Take those documents to your planning adviser before paying a deposit or arranging ground works.

Keep three questions separate: what you are buying, what you intend to do with it and which planning route applies to that proposal. Do not assume that insulation, plumbing or a different product name turns a temporary unit into a qualifying Class 3A dwelling.

What about a permanent garden dwelling?

Condition 7 of Class 3A sets a 32–45 m² external-footprint band, counted together with earlier Class 3 garden structures. S.I. No. 340/2026, Class 3A.

The area rule is only one part of the assessment. Use the full Class 3A planning guide to discuss the existing garden structures, access, remaining garden, services and occupation of the main house. Ask the adviser to identify any condition that needs further evidence.

Nua Living uses ICF construction, with concrete poured on site between permanent insulation layers. See our construction explanation and home specifications when comparing the written scope with another proposal. Compare construction separately from planning eligibility.

Is an office or hobby room a different question?

For non-habitable use, start with the garden-room planning guide. Tell your adviser if anyone will live or sleep in the building. Do not describe proposed accommodation as an office simply to use a different planning category.

What needs attention before work starts?

Conditions 16–18 require notification to the planning authority at least 14 days before work starts; the notification records use of the exemption and is not planning approval. S.I. No. 340/2026, Class 3A.

A Class 3A auxiliary dwelling follows the normal Building Control process, including a Commencement Notice, design and assigned certifiers, a competent builder and a Certificate of Compliance on Completion. Department Circular BC07-2026.

Keep those processes separate in the programme. Use the pre-start paperwork guide to discuss responsibility for the council submission, Building Control documents and professional appointments. Do not order site work while the planning route remains unresolved.

What should you bring to a site discussion?

• The supplier’s drawings and specification.
• Your intended use and the proposed location in the garden.
• Details of existing garden structures and access constraints.
• A list of questions that still need a planning or technical answer.

If you are considering a permanent Nua Living dwelling, request a callback and free site visit. Explain the proposal first so the discussion starts with the correct use and scope.