Front Roof Windows and Planning: The 2026 Exemption Explained for Dublin and Naas Homes

For years, the advice for most Dublin homes was simple: a roof window on the back slope was usually fine without planning permission, but one on the front slope meant a planning application. That changed on 27 July 2026, when new exempted development regulations came into force for houses.

If you have been putting off brightening a front bedroom, landing or attic room because of the planning step, this guide explains what the new rule covers, which window sizes fit inside it, and when you should still check with your council before any work starts.

This is general guidance, not legal advice. For a firm answer on your own house, the council can give you a formal declaration (more on that below).

What changed in July 2026

The government amended the Planning and Development Regulations 2001 with a set of new exemptions for houses. One of them, S.I. No. 344 of 2026, added two new classes:

• Class 1B: a dormer roof extension to the side or rear of the house, with limits on volume, height and setback from the eaves.
• Class 1C: the insertion of roof lights on the existing front roof plane of the house.

These are national regulations, so they apply across Dublin City, Fingal, South Dublin, Dún Laoghaire-Rathdown, Kildare and Wicklow, not just in one council area.

The two conditions for front roof windows

Class 1C comes with two conditions. A front roof window is only exempt if both are met:

If you want three windows on the front, or a bigger window than the limit, the exemption does not apply and you would need planning permission as before.

Which roof window sizes fit the limit?

This is where many homeowners will be caught out. Most popular roof window sizes are taller than 100 cm. Using the size codes on the VELUX Ireland size guide (width x height):

Of the common pitched-roof sizes listed by VELUX, the MK04 is the one that sits inside the limit. Smaller sizes from VELUX and other brands such as FAKRO and Keylite may also fit, but always check the outer frame dimensions on the manufacturer's sheet before ordering.

The regulation does not spell out whether "length" and "width" mean the outer frame or the glass. We plan to the outer frame size, as that is the cautious reading. If your plans are close to the limit, confirm with the council first.

For help choosing between brands and glazing, see our VELUX, FAKRO, Keylite and Roto comparison and our guide to double vs triple glazed roof windows.

What about rear and side roof slopes?

Class 1C only covers the front roof plane.

• Rear slope: Before the new rules, Dublin City Council's own guidance, as reported by the Irish Times, treated Velux windows to the rear as exempt. That relies on the general exemption in section 4(1)(h) of the Planning and Development Act 2000 for works that do not materially affect the external appearance of the house in a way that is inconsistent with its character or its neighbours.
• Side slope: The same guidance said side and front Velux windows were not exempt. The new front exemption does not mention side slopes, so a side roof window on a semi-detached or end-of-terrace house is still one to check before you go ahead.
• Dormers: A dormer is not the same as a roof window. Dormers to the side or rear now have their own exemption (Class 1B) with separate limits. Front dormers are not covered.

When the exemption will not apply

Even a single small front roof window can still need planning permission in some situations. Dublin City Council's Section 5 page notes that exemptions do not apply if the development is:

• in an Architectural Conservation Area, which applies to a number of older streets and town centres across the Dublin area (your council's development plan maps show where they are);
• in a Special Amenity Area Order area; or
• a protected structure.

There are also wider restrictions under Article 9 of the Regulations, and planning conditions on your original house permission can matter too. Newer estates in North Dublin, Lucan and Naas sometimes have conditions about future alterations.

For protected structures, the rules are stricter again. In a 2020 decision on a protected house on Brighton Road, Rathgar, the planning board found that reinserting a small rooflight in the front roof slope was not exempted development. Owners of protected structures can ask Dublin City Council's conservation section for a Section 57 declaration setting out what works can be done without permission. Our guide to roof repairs on protected structures covers this in more detail.

How to get a firm answer: a Section 5 declaration

If you are unsure, you can ask your council for a formal ruling under section 5 of the Planning and Development Act 2000. In Dublin City, the council's page says you need:

• a completed Section 5 application form;
• the relevant site maps; and
• a fee of €80.

Dublin City Council says a planner will respond with a decision within four weeks, and the decision can be referred onwards to the national planning board. Other councils, including South Dublin, Fingal, Kildare and Wicklow, run their own Section 5 process, so check their websites for current forms and fees.

A declaration is also useful when you sell. A buyer's solicitor may ask whether front roof windows had permission or were exempt, and a written answer is easier than an argument.

Planning is only one part of the job

An exemption from planning does not mean anything goes. The council's guidance on the 2026 regulations is clear that Building Regulations and Fire Regulations still apply. Before fitting a front roof window, a good roofer should check:

• Roof structure: cutting a rafter to fit a window needs proper trimming. Older Dublin City terraces and 1930s semis often have smaller rafters than modern homes.
• Roof covering: the right flashing kit for your slates or tiles. Deep-profile concrete tiles, common on estates in Lucan and Naas, need a different flashing from flat natural slate.
• Weather exposure: front slopes facing south-west take the brunt of Irish wind-driven rain. Correct flashing and underlay detailing matter more than the window brand.
• Inside finish: insulation around the lining, and where condensation will go. Our roof window flashing checks explain common leak points.
• Access: front roof work over a footpath or a busy road may need scaffolding and, in some cases, a council licence. See our guide to scaffolding and access for terraces.

Please do not go up on the roof to measure. Rafter spacing and existing window sizes can be checked from the attic or by a roofer with proper access.

Quick checklist before you order a front roof window

• No more than two roof windows on the front slope, counting any already there
• Each window no more than 90 cm wide and 100 cm long (check the outer frame)
• House is not a protected structure and not in an Architectural Conservation Area
• No planning conditions on your house that restrict roof alterations
• Side-slope or larger windows checked with the council (Section 5)
• Roofer has checked rafters, flashing type and access
• Building Regulations requirements discussed if the room is being converted

Thinking about a front roof window?

We fit and replace roof windows across Dublin City, North Dublin, South Dublin, Lucan, Bray, Wicklow, Naas and nearby areas. We can check your roof, recommend a size that suits the room and the new exemption, and fit it with the right flashing for your slates or tiles. If your plans need a Section 5 declaration or planning permission first, we will tell you before any work is booked.

Contact us by WhatsApp, call 083 066 3462, or email hi@perfectroofing.ie.