# Attic Conversion Structural Engineer Dublin | Floors & Dormers > Attic conversion structural engineer in Dublin: new floor joists, truss alterations, dormer steel and sign-off for habitable attics. Fixed fee before the visit. URL: https://structuralengineer.ie/attic-conversion-structural-engineer/ # Attic Conversion Structural Engineer in Dublin A new floor that can take a bedroom, a roof that still stands once the trusses are cut, and dormer steel designed before anyone climbs into the loft with a saw. [Call 01 270 9764](tel:+35312709764) [Get a fixed fee](#quote) _Image: New C24 floor joists and a steel beam in an attic conversion in an Irish semi-detached house_ - I.S. EN 1991-1-1 Imposed loads - I.S. EN 1991-1-3 Snow loads - I.S. EN 1993-1-1 Steel design - I.S. EN 1995-1-1 Timber design - TGD A Structure - TGD B Fire safety - TGD K Stairways Last updated: 14 October 2026 · Reviewed by Joachim Louw, CEng MIEI [StructuralEngineer.ie](https://structuralengineer.ie/) is a Chartered attic conversion structural engineer serving Dublin, Kildare, Meath and Wicklow. Joachim Louw (CEng MIEI) designs the new floor, any alterations to trusses or purlins, the steel for dormers and hip-to-gable conversions, and the support for the new stairs. He then inspects the work and signs it off. The ceiling joists in most Irish attics were sized for storage boxes, not a bedroom, so almost every habitable attic needs a new floor structure. Published 2026 Irish guides put the engineering fee for an attic conversion at €800–€2,500, within a total project cost of roughly €28,000–€75,000 in Dublin depending on dormers and finish. Your fee is fixed in writing before the visit. ## What happens on the first visit On the first visit the engineer goes into the attic to establish what kind of roof you have and how it is carried: trussed rafters, a traditional cut roof with purlins and struts, or a mix. That decides how much of the roof can be opened up, and what the new floor and any dormer steel have to do. - Identify the roof type: trussed rafters or a cut roof with purlins, struts and binders - Measure the existing ceiling joists, their span and what they bear on - Check the walls below that new floor beams and steel will bear onto - Measure the headroom at the ridge and the height available for a dormer - Check where the stairs can land and what has to be trimmed for the opening - Note water tanks, chimney stacks and party walls that affect the layout ## Why the existing ceiling joists can't be the new floor Ceiling joists in a typical Irish house were designed to hold up a plasterboard ceiling and some storage, often at a light imposed load. A habitable room is designed for 1.5 kN/m² of imposed load under I.S. EN 1991-1-1, plus the weight of the floor, partitions and furniture. Those are very different numbers. The usual answer is a new set of floor joists, typically C24 timber, spanning between load-bearing walls or onto new steel beams, laid between or alongside the old ceiling joists so the ceiling below isn't disturbed. The joist size, spacing and bearings come from the calcs. ## Trussed roofs, cut roofs and dormers Most Irish houses built from the 1970s on have trussed-rafter roofs. Each truss is an engineered triangle, and cutting any member removes what holds it together. Converting a trussed roof means designing replacement structure first, usually steel or timber beams at purlin level plus new floor joists acting as ties, and only then removing the truss webs. Older cut roofs with purlins and struts are often easier to open up, but the struts usually land on internal walls below, so the loads have to be re-routed onto new beams. Rear and side dormers need a structural opening in the roof: trimmers or steel carrying the cut rafters, and a dormer frame that ties back into the roof. Hip-to-gable conversions build up a new gable wall, which needs checking at its foundation. ## Fire, escape and the stairs Habitable attics bring Technical Guidance Document B (fire) and K (stairs) into play: a protected stair route, fire-rated doors to the rooms off it, and a stair with compliant pitch and headroom. These are not structural items, but the stair opening is. Trimming the floor for the new stair, and supporting it, is part of the structural design. ## Planning, the 2026 dormer exemption and selling a converted attic Since 27 July 2026, side and rear dormers are exempted development within limits, reported as about 30 m³ of added volume, set back from the eaves and no higher than the existing ridge. Front dormers still need permission. Check the regulations and your estate's original planning conditions before relying on the exemption. If the room is to be used or sold as a bedroom, it has to comply with the Building Regulations in full: structure, fire safety, stairs, ventilation and energy. An attic that doesn't comply is marketed as 'attic storage', and buyers' surveyors check. The engineer's opinion of compliance with Part A, backed by inspections during the work, is part of what lets you call it a room. For the full budget, read [attic conversion cost in Dublin](https://structuralengineer.ie/guide/attic-conversion-cost-dublin/). For headroom, fire and the 2026 dormer exemption, see [attic conversion regulations in Ireland](https://structuralengineer.ie/guide/attic-conversion-regulations-ireland/). ## What's included - Site visit and roof survey by a Chartered Engineer - New floor joist design with bearings - Truss or purlin alteration design - Dormer or hip-to-gable steel and framing - Stair opening trimming design - Calcs, drawings and steel schedule - Inspection before the floor and roof are closed in - Signed opinion of compliance with Part A Typical market range: **€800–€2,500** (attic conversion engineering; total project €28,000–€75,000 in dublin). Source: calculateroofcost.ie; constructors.ie; premierbuilders.ie, 2026. Fixed fee confirmed in writing before the visit. ## Attic company standard detail, online calcs or an engineer on site What gets checked, and what you can show a buyer's surveyor afterwards. | Check | Standard detail, no calcs | Online calcs, no visit | Chartered Engineer on site | | --- | --- | --- | --- | | Roof type and load paths checked in the attic | sometimes | No | Yes | | Floor joists sized for habitable use | assumed | Yes | Yes | | Truss alterations designed before cutting | No | assumed | Yes | | Walls below checked for new beam bearings | No | No | Yes | | Structure inspected before it is closed in | No | No | Yes | | Opinion of compliance to support 'bedroom' at sale | No | limited | Yes | Sources - [calculateroofcost.ie: attic conversion cost Dublin 2026](https://www.calculateroofcost.ie/attic-conversion-cost-dublin/) - [Constructors.ie: attic conversion cost and regulations](https://constructors.ie/blog/attic-conversion-cost-ireland-regulations-guide) - [Premier Builders: attic conversion prices Dublin](https://premierbuilders.ie/attic-conversions-prices/) - [Department of Housing: Technical Guidance Documents](https://www.gov.ie/en/collection/26ce3-building-regulations-technical-guidance-documents/) Talk to the engineer 01 270 9764 Mon–Fri 8:00–18:00. Callback the same working day. [Call now](tel:+35312709764) Fixed fee confirmed in writing before the visit. Standards we design to - I.S. EN 1991-1-1 Imposed loads - I.S. EN 1991-1-3 Snow loads - I.S. EN 1993-1-1 Steel design - I.S. EN 1995-1-1 Timber design - TGD A Structure - TGD B Fire safety - TGD K Stairways Before you book: costs and rules - [Attic Conversion Cost in Dublin (2026)](https://structuralengineer.ie/guide/attic-conversion-cost-dublin/) - [Attic Conversion Regulations in Ireland (2026)](https://structuralengineer.ie/guide/attic-conversion-regulations-ireland/) - [How Much Does a Structural Engineer Cost in Dublin? (2026)](https://structuralengineer.ie/guide/structural-engineer-cost-dublin/) How the job runs ## How an attic conversion is designed and signed off - 01 ### Call and fixed quote Describe the house and the conversion you want. You get a fixed fee in writing. - 02 ### Roof survey The engineer identifies the roof type, load paths, headroom and the walls below. - 03 ### Floor and roof design Joists, beams, truss alterations, dormer framing and stair trimming, with calcs and drawings. - 04 ### Inspection and sign-off Structure inspected before it is closed in, then the signed opinion of compliance. What the work involves ## Typical stages on site Illustrative images of typical work, not photographs of specific client projects. _Image: Rear box dormer framing under construction on an Irish semi-detached house_ Rear box dormer framing under construction on an Irish semi-detached house _Image: Steel beam at purlin level supporting cut rafters during an attic conversion_ Steel beam at purlin level supporting cut rafters during an attic conversion _Image: Trimmed stair opening with doubled joists for an attic conversion staircase_ Trimmed stair opening with doubled joists for an attic conversion staircase _Image: Finished attic bedroom with a dormer window in an Irish semi-detached house_ Finished attic bedroom with a dormer window in an Irish semi-detached house ### Typical before and after _Image: Before: unconverted attic with trusses, insulation and storage boxes_ Before Illustrative _Image: After: the same attic converted into a bedroom with a dormer window and a new stair_ After Illustrative Converting the attic? Get the floor, trusses and dormer designed before anything is cut. Fixed fee confirmed in writing before the visit. [Call 01 270 9764](tel:+35312709764) [Request a fixed fee](#quote) Questions ## Attic conversion engineer: common questions **Do I need a structural engineer for an attic conversion?** Yes, if the attic is to be a habitable room. The existing ceiling joists were not designed for bedroom loads, trussed roofs cannot be cut without replacement structure, and the stair opening has to be trimmed. Building Regulations Part A applies, and the engineer's opinion of compliance is what supports calling it a bedroom when you sell. **Can I convert an attic with a trussed roof?** Usually yes, but it takes more structure than a cut roof. The truss webs that are in the way can only come out once replacement beams, typically steel or timber at purlin level, and a new floor acting as a tie have been designed and installed. Headroom is the other limit, because trussed roofs are often shallow. **How much headroom do I need for an attic conversion?** A commonly used benchmark is 2.4 m of headroom over at least half the floor area for a habitable room, with the stair needing its own clear headroom under Technical Guidance Document K. Measure from the top of the new floor, which sits higher than the existing ceiling joists. A dormer is often what makes the headroom work. **Is an attic conversion a bedroom when I sell?** Only if it complies with the Building Regulations for a habitable room: structure, fire safety, escape, stairs, ventilation and energy. Otherwise it is marketed as attic storage, and the buyer's surveyor will check. Inspections during the work and an engineer's opinion of compliance with Part A are part of that case. **What areas do you cover?** Dublin and the Greater Dublin Area (Kildare, Meath and Wicklow). Site visits are booked from the Blackrock office. Site visit usually within 5 working days. ## Related services [### Extensions Foundations, steel and BCAR sign-off for rear and side extensions, including the new 45 m² exemption.](https://structuralengineer.ie/structural-engineer-for-extensions/) [### Load-Bearing Wall Removal Steel beam and padstone design, propping, inspection and a signed certificate for knock-throughs.](https://structuralengineer.ie/load-bearing-wall-removal/) [### Opinions of Compliance Engineer's certificate for past works when you sell, remortgage or regularise an extension.](https://structuralengineer.ie/opinion-of-compliance/) Next step Get a fixed fee for your attic conversion Call [01 270 9764](tel:+35312709764), or send the details and we'll call you back. Request a fixed engineering fee Prefer to talk? [Call 01 270 9764](tel:+35312709764). A live person answers during office hours.