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A Guide to House Extensions…...

Some of your most common questions answered:

How much does an extension cost?

You should allow €2,000 - €2,500+VAT/m2 for your house extension. But costs can vary depending on numerous factors:

· Single storey

· Two storey

· New kitchens/bathrooms required

· Structural steel required

Do I require planning permission?

Generally, you do not require planning permission for:

An extension to the rear of the house which does not increase the original floor area of the house by more than 40m2 and is not higher than the house. The extension should not reduce the open space at the back of the house to less than 25m2 which must remain private open space (back garden).

If your house has been extended before, the floor area of the extension you are now proposing and the floor area of any previous extension (including those for which you previously got planning permission) must not exceed 40m2.

Converting a garage attached to the rear or side of the house to domestic use provided it has a floor area of less than 40m2.

Building a garage at the back or side of a house so long as it does not extend out in front of the building line of the house and does not exceed 4m in height (if it has a tiled/slated pitched roof) or 3m (if it has any other roof type). This building will be exempt from planning permission once the floor area of all additional structures (both new and previously added) is limited to 25m2.

Building a porch to the front door so long as it does not exceed 2m2 and is more than 2m from a public road or footpath. If the porch has a tiled or slated pitched roof, it must not exceed 4m in height or 3m for any other type of roof.

Do Building Regulations apply when building a house extension?

Yes, it doesn’t matter if your house extension requires planning permission or not, you will need to ensure that you obey all relevant Building Regulations.

What to do next?

Book an online consultation with us:


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