- Published price ranges rarely reflect a specific home.
- Roof structure, stairs and finishes are the biggest cost drivers.
- A dormer typically costs more than a standard conversion, for good reasons.
- A written, itemised quotation is the only reliable point of comparison.
Why one number does not fit all
A converted attic is a bespoke construction project layered onto an existing house. The cost is driven by dozens of small decisions — some structural, some regulatory, some aesthetic — that vary from one property to the next. Anyone quoting a fixed figure without a survey is either working from a rough rule of thumb or hoping to price the work up later.
The main cost drivers
Roof structure
A cut-timber roof is usually the least intrusive structurally. A trussed roof needs engineered beams before the internal webs can be cut. A hipped roof may need a hip-to-gable adaptation for standing headroom. Each of these is a real cost, driven by material and by labour.
Floor strengthening
The existing ceiling joists are usually undersized for habitable use. Additional joists — steel or timber — are introduced to create a compliant floor. The size and span determine the specification.
Stairs
A straight stair off an existing landing is the simplest. L-shaped, U-shaped or bespoke stairs cost more. Where the stair requires headroom to be created above it — a rooflight or a small dormer — that is a separate cost.
Dormer or standard conversion
A dormer adds external cladding, structural work and additional roofing. A standard conversion keeps the envelope intact and typically costs less. Neither is inherently “better value” — it depends on the space you need.
Bathrooms and plumbing
Adding an en-suite involves waste routing, water supply, ventilation and waterproofing. It is one of the more significant single line items on a quotation.
Insulation and energy
A habitable attic must meet the current insulation standards. The build-up between rafters, the vapour control layer and the finished ceiling all need to work together. Compliance is non-negotiable.
Fire safety
Upgrading doors on the escape route, installing mains-wired interlinked alarms, and where relevant, sprinkler or misting systems for open-plan ground floors all contribute to the total.
Finishes
Floor coverings, tiling, joinery, sanitaryware, lighting and paint are usually the most visible part of the budget and the easiest to flex up or down. A calm mid-range specification usually reads better than a lavish one in a compact attic room.
Access and site conditions
Restricted access, party wall considerations, occupied neighbouring homes and tight urban sites all affect the price because they affect the pace and method of construction.
Professional input
Structural engineering, Building Regulations design input and certification are proper professional services and should be priced properly. A quotation that includes them is easier to trust than one that does not.
What this means for your project
Ask for a written, itemised quotation after a home survey. Understand what is in and what is excluded. Compare like for like, not headline against headline. The cheapest number on paper is very rarely the cheapest number by the time the project is finished.
What this means for your project
Every home is different. Use this guidance to ask the right questions and to shape your brief — but confirm what applies to your specific property with a home survey and appropriate professional input.
Frequently asked questions
- Why do you not publish price ranges?
- Because ranges without context are misleading. Two houses on the same street can end up in very different price brackets depending on roof structure, stair layout, whether an en-suite is included and the level of finish. A specific number needs a specific survey.
- Is a dormer always more expensive than a standard conversion?
- Almost always, yes — because the roof is opened, additional structure is added, external cladding is installed and the internal floor area increases. The additional cost is usually justified by additional usable space.
- Where should I focus if I want to control cost?
- Scope and finishes. Simpler stair layouts, one bathroom rather than two, standard tiling, and off-the-shelf rooflights all keep the numbers reasonable without compromising the structural quality of the conversion.
- Should I always take the lowest quote?
- No. Compare on scope, not on headline number. A lower number that excludes stairs, structural work, insulation upgrades or Building Regulations documentation is not really lower.
Start with a quick check of your attic.
Answer a few simple questions about your home and what you would like to create. We’ll give you an early indication of which conversion route may be worth exploring. A home survey is still required before suitability can be confirmed.
Or call +353 85 150 0853