If you are building an extension or making other changes to your existing house, you may need planning permission.

Extensions and conservatories will not usually need planning permission if they do not extend the floor area of the house by more than 40 sq m and are not higher than the house, but homeowners are advised to check this before any building work begins.

It is an offence to carry out any work that requires planning permission and the offence can result in heavy fines and imprisonment. If a genuine mistake has been made, it is possible to apply for permission to keep the development, but this permission may be refused and the development demolished.

You must place a notice of your proposals in one of a list of approved newspapers and then apply to the local authority within two weeks. Either before or on the day of application, a notice that can be clearly read must be put up on the site and should remain there for at least a month.

To apply for planning permission, you will need to fill out an application form, which is now available online at reachservices.ie. You will also need to submit detailed drawings of your proposed extension, copies of public notices and an application fee to your local authority. The current fee for an application to build a house extension or the conversion of a garage for use as part of the house is €34.

It can take over three months to get planning permission, or longer if the local authority's decision is appealed to Bord Pleanála.