Q. I live in an end of terrace house in the Dún Laoghaire Rathdown area and want to build an extension at the back of my house. As I am end of terrace my back garden extends wider than the back of my house. The extension I would like to build is less than 40sq m, but will be wider than my house. Do I need planning permission for this?

A. This is an interesting question, and one that I have been asked before. The planning and development regulations state that the following is exempted development: “The extension of a house, by the construction or erection of an extension (including a conservatory) to the rear of the house [subject to certain conditions]. . . ” I have heard it argued that an extension to the rear of an original house, which is wider than the house, is exempted development, so long as the extension is kept behind the line of the rear of the house.

However, I believe that this is incorrect. While, arguably, the regulations are not explicitly clear on this particular matter, my interpretation is that an extension should be fully behind the rear wall of the original house ie so that one could not view it if they were standing at the front of the house. Not only could building wider than the original house be construed as building to the side, it would materially alter the character of the house from the front, especially a terraced house.

In situations where a question arises as to what is or is not development/exempted development, my advice, depending on the circumstances, is to either apply for planning permission or to seek a ‘declaration’ on that question from the planning authority, under Part 1, Section 5 of the Planning and Development Act.

Otherwise, one is running the risk of proceeding with a development that is potentially illegal and possibly facing subsequent enforcement action.

It is also important to bear in mind that exempted development is subject to several strict conditions including the size and height of the development. These conditions are readily available to view on most Planning Authority websites, and one should familiarise themselves with the conditions prior to proceeding with a development.

Andrew O’Gorman, chartered building surveyor and member of the Society of Chartered Surveyors Ireland, scsi.ie

Subsidence fears

Q. I recently viewed a totally renovated house in Cork City that I am possibly interested in making an offer on. I like the house, it is in a good area and the asking price is reasonable. It has been totally dry-lined and redecorated inside and the outside has new external insulation front and back. A new extension of 10sq m approximately to provide a downstairs shower room and utility room have been added. The house is currently rented.

My problem is that this house is in an area known for subsidence and the house has not been underpinned. There will be difficulties with insurance cover. The usual signs of subsidence – cracking inside and out – will have been concealed by the renovation and by observation any problems will be difficult to detect. I have been asking myself why someone would not underpin before doing all the insulation work? Is there anything I can do to set my mind at ease before proceeding further? I would be grateful for any advice.

A. The question as framed, provides valuable information raising important issues warranting further consideration. The assumptions and suspicions expressed about the structural integrity of the property emphasises the dreaded “caveat emptor” (buyer beware) adage about purchasing without careful consideration.

The opinion that the price is “reasonable” for this area, might suggest that it is below the expected market value for this type of property? If so, this needs further examination.

As the property has been fully renovated, it should be checked for compliance with Planning, Building Control/ Building Regulations.

The recently constructed extension of approximately 10sq m also needs confirmation of compliance. This should be checked by a competent professional such as a local chartered building surveyor.

No information is provided about the property type, structure or age and this would have helped. However, it seems that adjacent properties have been underpinned and apparently the foundations were deficient. Sometimes proper foundations were non-existent in very old buildings built around, or before, the early part of the last century. If more recently built there could be other issues.

Evidently the house is in an area known for subsidence and seemingly the foundation has not been underpinned.

The cause and extent of subsidence needs to be determined and if the immediate location is also prone to flooding as this could be a contributory factor. The reference to anticipated difficulties with insurance cover needs further investigation.

You rightly suggest that recent renovations such as internal dry lining and external insulation may temporarily disguise latent defects such as cracking.

A combination of partly destructive and non-destructive tests using an array of probes and other investigative surveying/testing apparatus throughout the building, would assist in establishing how sound the structure is likely to be.

Selected key structural elements may require significant investigation and partial exposure and it would be prudent to also consider selectively exposing the foundations for inspection as this will examine the underpinning concerns.

All this presents a significant dilemma and can be difficult to cater for contractually. This obviously affects the seller who is unlikely to be willing to undertake such prior works as it is both disruptive and costly and undoubtedly has implications for the tenant.

If you still wish to proceed – and bearing in mind that it is unlikely that you will be allowed to carry out the rigorous tests outlined above prior to purchasing – you should still seek professional advice from competent professionals including your legal adviser and structural engineer prior to agreeing any deal.

You also need to address the planning and building regulations compliance issues by engaging a local chartered building surveyor. Naturally the costs of these tests and advice will have to be factored into the asking price and there may be some scope for negotiation there.

Armed with that information, hopefully you will be in a better position to make a more informed decision on how to proceed. You may well decide to walk away or else make an offer for the property which reflects any risk element.

It’s your call but in the absence of the tests, surveys and inputs from your solicitor and engineer, ‘caveat emptor’ is still the best advice.

Kevin Sheridan is a former chairman of Building Surveying Professional Group of the Society of Chartered Surveyors Ireland scsi.ie