Home energy guide
Rafter insulation cost and grants in Ireland
Understand insulation along a sloping roof and how its scope differs from insulation at attic floor level.
Last reviewed: October 2026
Indicative costs
DanannIQ uses irish 2026 installed rafter/room-in-roof insulation pricing for this guide, covering 2026 planning range. Where a stored median is available, the displayed range applies the existing DanannIQ planning spread. These figures are planning information, not quotations or guarantees.
Planning range for rigid rafter-level insulation including typical lining/finishing. Roof geometry, ventilation detailing, access and existing finishes can materially change the price.
These retained rates are DanannIQ planning assumptions, not published SEAI medians. An itemised contractor quote must confirm scope and actual cost.
Rafter level and ceiling level are different projects
Rafter insulation follows the sloping roof, bringing the intended roof space within the thermal envelope when correctly designed. Ceiling-level attic insulation lies over the ceiling below a cold attic. These approaches are not interchangeable, and adding both is not automatically the right design.
A usable room-in-roof or a conversion can need roof-level work, including junctions with gable walls, floors and any unheated eaves. Insulation alone does not turn storage space into compliant living accommodation. Structure, escape, stairs, services and permissions are separate considerations.
Design the roof as a complete assembly
Warm-roof and other roof-level arrangements differ in where the insulation and air/vapour-control layers sit. The existing covering, underlay, structure and intended room use determine the suitable approach. Ask a designer to confirm moisture control, weathering and roof ventilation rather than choosing a board thickness in isolation.
Room fresh-air provision and roof-space ventilation have different jobs. Review airtightness and ventilation before concealing junctions or service penetrations. SEAI’s SEAI homeowner’s guide to attic and rafter insulation explains the distinction from a conventional cold attic.
What the planning rate includes
DanannIQ retains €100–€180/m² for the insulated rafter/sloped-roof area, including typical lining and finishing. This is an existing planning assumption, not a published median. Do not substitute total house floor area for the measured roof area.
Roof geometry, access, ventilation details, existing finishes and unusual junctions affect scope. Roof repairs, major structural work and a full attic conversion are not established by that base rate. Ask an itemised quote to separate insulation from any conversion or wider renovation work.
Grant route and eligibility
DanannIQ treats rafter insulation as an OSS-supported measure, with €3,000 for detached or semi-detached/end-of-terrace homes, €2,000 for mid-terrace homes and €1,500 for apartments. It does not deduct a standalone Individual Grant for this project.
These amounts require a qualifying assessed OSS package, including pre-2011 construction and occupancy and the scheme’s required post-works performance. They are not automatic support for a conversion. Compare the routes and confirm the current schedule with SEAI One Stop Shop: eligibility, services and grant schedule.
Questions before committing
Confirm the thermal boundary, exact area, moisture and ventilation strategy, finishing scope and grant route with the designer/provider. If the attic will remain unheated storage, revisit the ceiling-level guide before choosing roof-level work. A grant estimate does not establish technical suitability or final approval.
Plan this upgrade with the rest of your project
Use the DanannIQ calculator to estimate this work alongside other home improvements. It provides indicative project ranges and potential grant information, not an exact contractor quotation.
Open the DanannIQ calculatorSources and methodology
Cost figures use the existing DanannIQ source record for Rafter insulation, checked on 2026-09-09. Grant information uses the existing SEAI - One Stop Shop grants record, checked on 2026-09-09. Confirm current rules and application requirements with the official SEAI source.
For more detail on DanannIQ cost ranges and potential grants, read the Methodology & data sources page or browse all upgrade guides.
Planning several measures? Use the SEAI grants overview and whole-project cost guide to put this upgrade in context.
Have a BER Advisory Report? Start your BER-guided plan.