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We've inherited planning permission, but we don't like the design


A well-designed extension makes good use of space and natural light to create a useful space

A well-designed extension makes good use of space and natural light to create a useful space

A well-designed extension makes good use of space and natural light to create a useful space

Q We have bought a house and have 'inherited' a planning permission for a two-storey extension, but we don't like the design. How can we change it?

A This is an issue which often arises. You're very wise to acknowledge where you don't like the design and to consider changing it. Regrettably, all too often people proceed and build in haste with 'inherited' permissions (from prior ownership or otherwise) and then live with the consequences - in some instances, for the rest of their life.

It's certainly possible to change the design and, depending on the nature, this may or may not even require planning permission.

Architect and design

Your first step should be to engage a registered architect to consider the design. This is a critical step to ensure you achieve a design that best reflects your needs and maximises the potential of your home. The process can start with a one-off consultation for an initial discussion on what might be possible. The cost of this is typically absorbed into agreed fees, should you choose to proceed further.

Simple changes such as re-organising the internal space, changes to proposed window types/format and the introduction of rooflights can usually be possible without permission, provided these do not cause overlooking.

More fundamental changes normally require permission, and your architect should talk you through the entire building and planning process, as well as the many other statutory requirements. Regardless of whether the final extension is a complete re-design or just alterations to your inherited design, your architect will normally look afresh at the whole house and guide you accordingly.

Changes and permission

Having to apply for permission certainly shouldn't be a deterrent to rectifying something which will be such a large investment and which should add long-term value to your home, not just financially, but more importantly in terms of quality and the enjoyment of your home.

If permission is required for the changes (and your inherited permission is still valid), a new application can usually be considered by the local authority as 'alterations to a previously granted permission', depending on the extent of changes. The precedence of your already granted permission should be acknowledged by the local authority and help with a new application.

The time involves a minimum of three months, but can stretch to five to six months if any additional information is sought. In the extreme case that a decision is appealed to An Bord Pleanala, the timescale can be extended further. However a well-considered application (together with a pre-planning consultation with the local authority, if required) should assist in a straightforward application process.

Even if you decide not to consider a new application, internal changes can be made which should be acceptable to the local authority, provided it doesn't alter the extension size or height, the external appearance or create new issues of overlooking. In such cases, you should still take guidance from an architect where items such as light, orientation and circulation must still be taken into account. Here are some common issues that can occur with poor design and reasons you may need to revise what you have inherited:

Orientation and light

Orientation and light are key considerations for an architect when designing an extension and can hugely contribute to the quality of the building. Poor orientation or access to light will therefore have the opposite effect, and designs which do not exploit the light or views available can be commonplace.

Orientation might be influenced by a particular view, a focal point in a garden or to enclose an external space such as a courtyard. It can also be used to prevent overlooking.

Light shouldn't just be considered in terms of how many windows there are to the walls of the extension, but how and where light enters. Roof windows, clerestory windows, opaque glazing and deflected light are all additional forms of getting light into a building. Simple alterations such as window heights (and window type) can also make a big difference and are worthy of consideration.

Internal layout and organisation

Layout of the internal space is crucial to a well-worked extension. Poor examples, such as failing to address the garden/external environment in the vicinity of the extension, or the extension being a walk-through area to get to the outside, can leave people living with and cursing these mistakes. A simple case may be a kitchen or seating area which would be better served by being a dead end space (if the size of extension allows) rather than compromised by people constantly walking through.

A well-worked extension should therefore properly organise the internal layout and fully exploit the potential of the available external area. If done well (and with due consideration to landscaping), your extension can even use part of the external area to become like another room to the house.


Poor design can create overlooking issues from or to a neighbouring property. While this may not have been raised as an issue with the inherited permission, walking directly out of an extension to see your neighbour doing his early morning stretching routine next door can be a reflection of a poorly thought-out extension! Landscaping and screening can also play a big role here.

Similarly, your own privacy should be fully thought-out in terms of window locations and orientation. Good design should prevent this - or at least limit this - through careful consideration, orientation and planning.

Structure and services

Poor consideration of structure and services can lead to expensive and unnecessary costs, as well as detailing headaches at a later stage. Your architect will typically look at both the existing and proposed structures/services and advise on the requirements of a structural engineer or other consultants, as required. A well thought-out design should consider its buildability/cost as well as environmental impact.

Similarly, the location of existing and proposed services should be well thought-out, such as existing foul and surface water drains traversing the area of the extension, existing electricity meters and locations of proposed services, such as downpipes and outlets. Poor locations or issues at construction with existing services are a typical indictment of poor design from the outset.

The underlying principle for any building project is: better get it right than fast.

Diarmuid Cronin is a registered RIAI architect and director of Cronin Architects, covering residential and other sectors. Visit croninarchitects.ie

Do you have a design dilemma we can help you with? designclinic@independent.ie. Advice provided is for guidance only and readers are advised to seek professional assistance for any proposed project.

Sunday Independent