Do I need planning permission to add a conservatory?

Q We have bought a three-bed semi-detached home in need of some modernisation

Q We have bought a three-bed semi-detached home in need of some modernisation. We want to knock a wall between the kitchen and dining room as well as take down the back wall and build a conservatory to open up the entire space.

We are wondering if we need any planning permission or if we have to comply with any building regulations to do this?

AThere are basically two external/third party controls over building works including planning permission and building regulations. Planning permission is concerned with the use of a building together with the overall appearance and general environmental conditions whereas building regulations are concerned with the quality of construction and health and safety issues.

Generally speaking works of this nature are exempt from planning permission.


However there can be certain restrictions. In particular the conservatory would have to be located to the rear (not to the side or front) of your house, should not exceed 40sq m, taking account of other extensions as well and there should be at least 25sq m of open space remaining after the conservatory has been built.

Also, there should be no windows within a metre of any side boundary.

There can also be some further restrictions depending on the type of property and its location.

You can also have situations where the normal exemptions have been “conditioned out” in previous planning permissions. Ensure that this has been properly examined before doing any work.

It would also be prudent to have a site-specific inspection carried out.

As regards the building regulations, the obligation is to carry out the works in accordance with the relevant building regulations.

However there is no third-party involvement in this process and so it is highly unlikely that the works will be checked or inspected by the local authority.

But if you are borrowing money to do the works or if you are selling the property on, you will be asked to provide a certificate of compliance with the building regulations.

Theoretically you could bring in a professional to provide a certificate on completion of the works as such certificates are often purely based on a visual inspection.

But it is obviously much better to seek professional advice early on and seek clarification as to what the relevant building regulations are and to have the works inspected periodically so that there is no ambiguity or uncertainty over this.

For example if a professional looks at a finished floor, they will assume that insulation has been incorporated, as the actual responsibility is on the builder to incorporate this, but it is not possible to see this in a final inspection. If periodic inspections are being carried out, one of them could and should be inspected before the floor is laid.

Val O’Brien is a chartered building surveyor and member of the Building Surveying Professional Group of the Society of Chartered Surveyors Ireland