What does a roof window installation cost in Ireland?
Source reviewed with 4 external references. How we review guides
A roof-window quote can describe two very different jobs. A straight replacement uses an existing opening and is normally the simpler project. Installing a new window means opening the roof, integrating flashing and underfelt, insulating the reveals and completing the internal lining. Comparing those two prices without comparing scope is misleading.
VELUX Ireland publishes a broad average of €1,400–€1,800 to supply and install one replacement roof window. A separate reviewed Irish self-build guide estimates €1,200–€2,500 installed for a roof window including flashing. These are budgeting references, not a national tariff; size, glazing, roof covering, access and internal finishing determine the property-specific quote.[1][2]
This guide explains what should be surveyed before ordering, which details prevent leaks and cold bridges, and how to ask for a quote that includes the finished room rather than only the window unit.
Published Irish roof-window cost references checked October 2026
| Job | Published supply-and-install reference |
|---|---|
| Straight roof-window replacementVELUX Ireland broad average for one replacement in an existing opening. | €1,400–€1,800[1] |
| Roof window including flashingReviewed Irish guide estimate; confirm whether a new opening and internal finishes are included. | €1,200–€2,500[2] |
| Triple-glazing upgradeGuide estimate over its double-glazed reference specification. | €300–€500 extra[2] |
Prices are typical 2026 estimates and vary by job, condition and location.
Replacement and new installation are different scopes
VELUX describes its replacement service as fitting into the existing roof opening, without structural work. That is why its €1,400–€1,800 average should not be applied automatically to a new opening, a changed window size or an attic conversion. Ask the surveyor to state whether the existing aperture, rafters, lining and flashing can remain.[1]
- Straight replacement in an existing opening, with the same or a compatible size.
- Replacement that enlarges the opening or changes the roof structure.
- Completely new opening through slates or tiles, underlay, battens and ceiling.
- Single window, paired windows or a combination requiring additional structural support.
If the room has staining or damp around the old window, ask the contractor to identify whether the cause is failed flashing, condensation, a roofing defect or the window itself. Replacing the frame without correcting the cause can leave the same problem behind.
Specification and weathering details that affect price
The quote should identify the exact window model, dimensions, opening method, glazing and flashing kit. The flashing must suit the roof covering and its profile. External weathering, underfelt connection, insulation around the frame and correctly formed internal reveals are separate details that all affect performance.
- Roof material and pitch, including whether slates or tiles must be replaced.
- Access equipment, scaffolding and protection against rain during the opening.
- Double or triple glazing, acoustic options, solar control and safety glazing where required.
- Manual, electric or solar operation, blinds, sensors and electrical work.
- Plasterboard, insulation, skim coat, painting and disposal of the old window.
SEAI's rooflight guidance notes that rooflights form part of the roof and highlights consultation with the planning or conservation authority for protected structures, architectural conservation areas or changes affecting appearance. Planning circumstances are property-specific, so confirm them before ordering when the proposal changes the roof externally.[3]
What a complete quote should state
- Whether the price is replacement-only or includes forming a new structural opening.
- Window manufacturer, product code, size, glazing, U-value and warranty.
- Flashing, underfelt collar, insulation collar, drainage and replacement roof covering.
- Scaffolding, access, room protection, making good, plastering and decoration.
- Electrical connection for powered models and who performs any regulated work.
- VAT, waste removal, start date and the remedy if hidden roof damage is found.
The CCPC recommends written quotes, clear scope and payment records for home-improvement work. Where hidden timber damage is possible, agree how photographs, a revised price and your approval will be handled before extra work proceeds.[4]
A roof-window request you can adapt
'Please survey and quote for [replacing an existing roof window/installing a new roof window] at a [house type] in [county]. The roof covering is [slate/tile/other], the room is [finished/unfitted], and access is [describe]. Please specify the window, glazing and flashing system and include roof opening work, weathering, insulation, internal lining, plastering, access equipment, disposal, VAT and warranty. State what decoration, electrical work, structural work and planning checks are excluded. Photos and approximate measurements are attached.'
Frequently asked questions
What does replacing a roof window cost in Ireland?+
VELUX Ireland publishes a broad average of €1,400–€1,800 to supply and install one replacement roof window. Your exact quote depends on its size, specification and whether the existing opening can be reused.[1]
Does a roof-window price include plastering and painting?+
Not necessarily. Some prices cover the exterior window and flashing but exclude internal lining, skim coat and decoration. Ask for each finishing stage in writing.
Why does a new roof window cost more than a replacement?+
A new opening can require cutting and supporting the roof structure, altering slates or tiles, connecting underfelt, adding insulation and forming new internal reveals. A straight replacement can reuse the existing aperture.
Do I need planning permission for a roof window?+
It depends on the property and proposal. Protected structures, conservation areas and changes to the building's appearance need particular care. Ask the local planning authority when the position is uncertain.[3]
Sources and editorial notes
Numbered references link claims in this guide to the sources below. Sources were accessed during the article's research or latest material review.
- [1] VELUX Ireland - Replacement supply and fit service
- [2] Planning Permission Ireland - Roof windows in Ireland
- [3] SEAI - Rooflights and dormers guidance
- [4] CCPC - Home improvement and building work disputes
Official guidance and further reading
These links are further reading and do not substantiate every estimate above.