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Do I need planning permission or Building Control Approvals?

To help you understand these issues we detail below some of the "conditions" attached to planning permission and Building Regulations. (These apply to Northern Ireland only) Wales Scottish, England, Eire regulations are quite different - You should in all instances take local advice.

Do I need permission for a Conservatory?

According to "Your Home and Planning Permission" - A Guide for House Holders in Northern Ireland a conservatory attached to the house will be treated as an extension and Rules A - F in section 1 "Building an Extension" will apply.

A Free Standing Conservatory will be considered under the Rules in Section 6

You will find the "sections" and very detailed explanations of all that involved at Householders Guide

Below we detail the main points with regards to planning permission for extensions / conservatories in Northern Ireland.

Building an Extension / Conservatory

Do I need permission to extend my house?

No, where the proposed extension complies with Rules A - F of Section 1

Rule A. The size of the extension must not be more than:

-Terraced house: 50 cubic metres or 10% of the original house volume, whichever is the greater

-Any houses in a Conservation Area: 50 cubic metres or 10% of the original house volume, whichever is the greater

-Any other house (detached or semi-detached): 70 cubic metres or 15% of the original house volume, whichever is the greater.

Illustration 1: Building an extension (Note 2 and Note 3)

Three identical extensions but only the extension at house 'A' would not require planning permission. At house 'C', the existing garage was added after 1 October 1973 and is therefore treated as an extension. The volume of the garage (44m3) plus the proposed extension (30m2) would exceed the stated allowance (70m3) and so planning permission would be required.

At house 'B', planning permission would be required because the extension would be within 5 metres of an existing building belonging to the house, causing that building to be treated as if it were part of the extension. The combined volume again exceeds the stated allowance.

Finally, at house 'A', the existing garage would not be treated as an extension as it would remain beyond 5 metres from the house and the proposed extension.

Rule B. The design and materials to be used to build the proposed extension must be in keeping with the main house.

Rule C. No part of the extension should be nearer to any road than the part of the original house nearest to the road.

Rule D. No part of the extension should be higher than the highest part of the existing roof of the house.

Rule E. The extension should not be more than 4 metres high if it comes within 3 metres of the boundary of the property (see Illustration 2). Height is to be measured from ground level, measuring the level of the surface of the ground immediately adjacent to the building or if it is not uniform, the level at its highest adjacent part.

Rule F. The ground area covered by the extension and any other buildings within the boundary of the property (excluding the original house) must not be more than half the total area (not counting the ground area of the original house).

Illustration 2: Building an extension (Rule E)

Note 1: In all cases size is calculated from external measurement, and there is an upper limit of 115 cubic metres. Note 2: Any extension built since 1 October 1973 will not be treated as part of the original house volume. It will therefore be necessary to subtract the volume of any existing extension from the allowances specified above. The amount left over (if any) is the amount, which you can extend without planning permission providing the proposed addition also complies with Rules B to F (see Illustration 1). Note 3: In some cases other buildings on your property will be treated as extensions and will reduce the allowances for extending your house.

If an extension to your home comes within 5 metres of another building belonging to the house (e.g. Garage, shed or greenhouse, etc) that building will be treated as if it were part of the extension (see Illustration 1).

Any building added to your property which is more than 10 cubic metres in volume and which is within 5 metres of your house is treated as an extension and so reduces the allowances for further additions to the house without planning permission (see Illustration 3).

If you live in a house which is a listed building or is in a Conservation Area, all additional buildings which are more than 10 cubic metres in volume, regardless of the distance from your house, are treated as extensions and reduce the allowance for extending without planning permission. Note 4: The figures given for maximum sizes in Rule A represent the total amounts which can be built without planning permission. If, for example, you are making an addition to the roof of your house and also extending the house. The volume of both structures added together must not exceed the relevant amount shown at Rule A. Note 5: If you live in a house, which is a listed building, it is likely that you will need Listed Building Consent for the building operations covered in this report. Your local planning office will advise if such consent is required.

Illustration 3: Building an Extension (Note 3)


Generally speaking conservatories on residential property are exempted under Building Regulations.

Below are some of the Exemption Criteria - under the Building Regulations (Northern Ireland) 2000 (as amended). These criteria must be met for a conservatory extension to be classified as exempt:

a) The extension walls are substantially glazed. Must have at least half the area of the walls formed of windows. Must have at least three quarters of the area of the roof formed of glazing, polycarbonate sheets or similar translucent material.
b) The extension has a floor area not exceeding 30sq m.
c) The extension is sited at ground level.
d) The extension is permanently separated from the remainder of the property by means of an external quality door.
e) Any radiator within the conservatory is controllable. (If fixed heating installations are proposed, they should have their own separate temperature and on/off controls).
f) The glazing satisfies the requirements of part N, Schedule 1 (toughened/safety glass).

Integral conservatories are no longer allowed. Conservatories must be separated by an external quality door.

Conservatories should not be located where they will restrict ladder access to windows serving rooms in roof or loft conversions, particularly if any of the windows are intended to help escape or rescue if there is a fire.

Any new structural opening between the conservatory and the existing house will require building regulations approval, even if the conservatory itself is an exempt structure.