A modular, prefabricated or timber-frame house in Northern Ireland is, for planning purposes, a dwelling. The way it is built does not take it outside the planning system, and it does not create more generous rules than a conventional house. If you want to put a modular home on a plot, in a garden, or in the countryside, you should plan for the same planning permission and policy tests as any other new house.
The same permission as any other dwelling
Planning permission is required for development, including the erection of a building. A new modular home is a new dwelling. It is not permitted simply because it arrives in sections or can be assembled more quickly than a traditional build.
nidirect is clear that you need to apply for planning permission to build a separate house in your garden, or to use a building or caravan in your garden as a separate residence for someone else. A modular unit used as a home in those circumstances should be treated in the same way.
If the unit would replace an existing dwelling, or convert or reuse an existing building, different policy tests apply, but it is still assessed as a dwelling, not on the construction method alone.
Countryside policy: PPS 21 and Local Development Plans
Outside settlement limits, new houses are carefully controlled. Planning Policy Statement 21: Sustainable Development in the Countryside (PPS 21) requires a new dwelling to fit a defined Policy CTY 1 route. Those routes include a dwelling on a farm (CTY 10), a replacement dwelling (CTY 3), a small gap site within an otherwise substantial and continuously built-up frontage (CTY 8), a dwelling within an existing cluster (CTY 2a), the conversion and reuse of an existing building (CTY 4), and, in more limited cases, personal or domestic circumstances (CTY 6) or the essential needs of a non-agricultural business (CTY 7).
A modular home does not create an easier countryside category. If the site would not be acceptable for a conventional house, it is unlikely to be acceptable for a modular one.
Policy CTY 9 allows a residential caravan or mobile home only temporarily, in exceptional circumstances, such as while a permanent dwelling is built, or for compelling site-specific personal or domestic circumstances. Permissions are normally limited to three years, which may be extended in particular cases. PPS 21 states that permission will not be granted for a permanently sited residential caravan or mobile home in the countryside. A typical permanently sited modular or timber-frame house is assessed as a permanent dwelling, not under Policy CTY 9.
Whether PPS 21 still applies depends on the council. Retained regional policies are applied with the Strategic Planning Policy Statement until a council adopts a Plan Strategy, after which the Local Development Plan takes the primary role. Confirm the current policy with the planning office, and see our page on rural planning. Siting, design, access, integration and drainage still have to be acceptable.
Building control is separate
Planning permission and building regulations are different approvals. The current standards are the Building Regulations (Northern Ireland) 2012. The Department of Finance is clear that if you intend to erect, alter or extend a building, or to make a material change of use, you must first seek approval from your district council.
A new modular dwelling will normally need building control approval as well as planning permission. Do not assume that a factory-made unit is exempt.
How we can help
Patrick O’Reilly, Senior Planning Consultant at NI Planning Permission Ltd, is a chartered planner and a Full Corporate Member of the Irish Planning Institute (MIPI). We can advise whether a site has a realistic policy basis for a new dwelling, including a modular home, and we can prepare a planning application where you decide to proceed. We cannot guarantee that permission will be granted, and we do not issue building control approvals.
Frequently asked questions
Does a modular home need planning permission if it is moveable?
Many modular homes are designed to stay as permanent houses, and they are assessed as dwellings. Even a caravan used as a residence will often need planning permission. A supplier’s label is not decisive.
Can I put a modular home in a field I own?
Only if there is a policy basis for a new dwelling on that site, and if the siting, design and other requirements are acceptable. Ownership of the land is not enough.
Is a modular house treated as a caravan under Policy CTY 9?
CTY 9 is a temporary, exceptional policy. It is not a route to a permanent house. A permanently sited modular home is generally assessed as a dwelling.
Do I still need building control if I have planning permission?
Yes, unless building control confirms that an exemption applies. The two systems are separate.
Request planning help
If you are considering a modular, prefab or timber-frame home in Northern Ireland, get advice before you place an order or start on site. Enquire through our contact form or call 028 9591 6888. Our free planning guides include a guide to a house in the countryside.
NI Planning Permission Ltd, Scottish Provident Building, 7 Donegall Square West, Belfast BT1 6JH. Email info@niplanningpermission.co.uk.
This page is general information only. It is not a formal determination or a guarantee of any particular outcome. Check the current position with the relevant council.