Building and renovation

Attic conversion

Converting an attic to habitable space, including stairs, insulation and fire separation.

Whether this needs a licence in Ireland

Ireland

Licence required

Building Control notification and assigned certifier

Building Control notification and assigned certifier, issued or supervised by the Local authority building control. Ask for the registration number before the work starts and check it on the public register. Check the register: www.gov.ie

Wording approved by Talqero; not yet reviewed by a solicitor

Local authority building controlwww.gov.ieChecked 11/10/2026

Attic conversion: what the job involves

Turning the roof space into usable room: a floor strong enough to use, a proper stairs, insulation, roof windows or a dormer, and the fire separation the building regulations ask for. Many Irish attic conversions are finished as storage rooms because a habitable bedroom has stricter rules.

Also asked for as: loft conversion · dormer · attic room · convert attic · attic stairs

How the job is usually done

Survey: head height under the ridge, roof structure (traditional cut rafters or trussed rafters), water tank, and room for a stairs.
Design: decide habitable room or storage, stairs position, dormer or roof windows, and get an engineer’s design if trusses or rafters are altered.
Confirm planning: a rear or side dormer within the exemption, roof lights, or an application for a front dormer.
Structure: strengthen or add floor joists, trim openings, and form the dormer if there is one.
Stairs, fire doors and fire-resisting floor and enclosure to the stairs; escape windows and smoke alarms.
Insulation between and under the rafters, ventilation, electrics, heating and plastering.
Flooring, finishing and sign-off; record whether it is habitable or non-habitable.

Attic conversion: what is included

Usually included

Floor strengthening and boarding
Roof windows or dormer as specified
Insulation, plasterboard and skim
Stairs and the fire separation designed for the conversion

Usually not included — agree it separately

Design, engineer and any planning fees
Moving the cold water tank or heating, unless agreed
Electrics by a registered electrician, unless included
Built-in storage, flooring finishes and decoration

Materials and who supplies them

Floor joists, steel or engineered timber to the engineer’s design
Rigid or mineral insulation, vapour control layer, plasterboard
Roof windows or dormer materials, stairs and fire doors

How long it takes

Usually four to eight weeks on site; a dormer, trussed rafters needing structural redesign, or moving the water tank and heating add time.

When to book

Can be done in any season since most work is inside, but dormers and roof windows need a dry spell for the few days the roof is open.

Attic conversion: the rules in Ireland

What the official sources say, checked against them on the date shown. A summary, not legal advice — follow the link to read the rule itself.

Since 27 July 2026, a dormer to the side or rear is exempt up to 30 m³ of internal volume, no higher than the ridge and set back at least 20 cm from the eaves; up to two front roof lights of at most 100 cm by 90 cm are exempt. A front dormer, a protected structure or a conservation area needs planning permission.
Applies to: the homeowner
Planning and Development (Exempted Development (Act of 2000)) (No. 7) Regulations 2026, S.I. 344 of 2026, Classes 1B and 1C · sdcc.ie · Checked 9 October 2026
Converting a roof space into habitable rooms adds a storey: the stairs must be enclosed in fire-resisting construction with self-closing fire doors, the new floor separated by fire-resisting construction, each new room given an escape window or roof light, and smoke and heat alarms provided throughout the house.
Applies to: the designer and the builder
Building Regulations Part B — Technical Guidance Document B Volume 2, 1.3.6.5 and Appendix D · gov.ie · Checked 9 October 2026
Work that is not exempted development generally needs a Commencement Notice lodged with the council’s Building Control Authority through the BCMS portal 14 to 28 days before it starts. An extension of more than 40 m² also needs statutory certification — a design certifier, an assigned certifier and a Certificate of Compliance on Completion — unless the owner opts out for a domestic extension, in which case the building regulations still apply in full.
Applies to: the homeowner and the builder
Building Control Regulations 1997 to 2015, including the Building Control (Amendment) Regulations 2014 (S.I. 9 of 2014) · irishstatutebook.ie · Checked 9 October 2026
Where more than one contractor works on the job, there is a particular risk (deep excavation, heavy steel, asbestos, a fall from height), or the work lasts more than 30 days, the homeowner must appoint a Project Supervisor Design Process and a Project Supervisor Construction Stage in writing, and keep the safety file. Work lasting more than 30 days or 500 person-days must also be notified to the HSA.
Applies to: the homeowner, as client
Safety, Health and Welfare at Work (Construction) Regulations 2013 — HSA, Getting Construction Work Done Safely: Guide for Homeowners · hsa.ie · Checked 9 October 2026

What attic conversion costs, and why

What jobs on Talqero came to

Not enough comparable jobs yet to publish a range here. Talqero shows a price range only once at least five comparable jobs, agreed prices or offers exist — a range from fewer would describe a handful of jobs, not the market. Post your job and compare the offers you get.

What affects the price

Roof type: cut rafters convert more easily than trussed rafters
Dormer or roof windows only
Stairs and fire separation needed to make it a habitable room
Moving the water tank, plumbing and heating
Head height and how much floor area is usable
VAT: building work on a home is charged at the reduced 13.5% rate by a VAT-registered builder, unless materials are more than two-thirds of the price (Revenue’s two-thirds rule)
VAT: building work on a home is charged at the reduced rate of 13.5% by a VAT-registered business — unless the materials come to more than two-thirds of the price, when Revenue’s two-thirds rule applies the goods rate to the whole job. Ask whether a quote includes VAT.

Paperwork to ask for at the end

The engineer’s design and sign-off for the structure
A written opinion on compliance with planning and building regulations, stating whether the room is habitable
Electrical Completion Certificate for new circuits
Product guarantees for roof windows and insulation

Safety

Never cut or remove a trussed rafter without an engineer’s design: every member of a truss carries load.
Older attics can hide asbestos in the water tank, lagging or insulation; ask before anything is disturbed.
A bedroom in the attic needs a way out in a fire; do not lock escape windows with a key.

Attic conversion: before you hire

Questions to ask a tradesperson

Will this be certified as a habitable room, or as storage?
Who is designing the structure, and will they sign it off?
Is the stairs, fire separation and escape window included?
How will the existing house be protected from dust and weather?
Is VAT included?

What you can do yourself

Clearing the attic and measuring head height are useful; boarding over joists for storage is possible but anything structural or a habitable room is not DIY.

What to put in your task

What do you want to use the attic for?
What does the roof structure look like inside?
How high is it from the attic floor to the ridge?
How would you like light in?
What type of house is it?

Photos that help

The attic from the hatch, showing the roof timbers
A tape measure from the joists to the underside of the ridge
The landing below, where the stairs could go
The roof from outside, front and rear
The water tank and any pipes or cables in the attic

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Questions about attic conversion

Does attic conversion need a licence in Ireland?

Yes. Building Control notification and assigned certifier, supervised by the Local authority building control. Source: www.gov.ie. Ask for the registration number and check it on the public register. Wording approved by Talqero; not yet reviewed by a solicitor.

What is the difference between a habitable and a non-habitable attic conversion?

A habitable room meets the building regulations for living in, including fire separation, a compliant stairs and an escape window. Many conversions do not meet those, often because of head height or the stairs, and are sold as storage. Buyers’ solicitors check, so get the description right in writing.

Do I need planning permission for an attic conversion?

The internal work does not, and since 27 July 2026 a side or rear dormer up to 30 m³ and up to two front roof lights within a size limit are exempt. A front dormer, a bigger dormer, a protected structure or a conservation area needs permission.

Can every attic be converted?

Most can be made into useful storage. A habitable room needs enough head height, room for a proper stairs and a roof that can be adapted. Trussed rafters, common in houses from the 1970s on, can be converted with an engineer’s design but cost more.

Often booked with attic conversion

Builders