A loft conversion turns unused roof space into a habitable room such as a bedroom, bathroom or office, with a proper staircase, insulation, fire protection and natural light from rooflights or a dormer.
Cost is usually the first question about a loft conversion, so here is the guide for Wales: £27,500–£60,000 including VAT. We cover the whole of Gwynedd, with Bangor, Gwynedd, Llandudno, Holyhead and Caernarfon among the main centres. Because each UK nation sets its own rules, we check the requirements in Wales for your property, then put a firm price on paper following a free survey.
- Guide price
- £27,500–£60,000 inc VAT
- Time on site
- 6–10 weeks on site
- Planning rules
- Wales
- Price level
- About 8% below the national guide
- Towns listed
- 4
- Survey
- Free, with a written quote
Loft conversions prices in Gwynedd
Every figure below is a guide for a loft conversion in Gwynedd, inclusive of VAT. Regional pricing for Wales works out about 8% below the national guide, and the overall span is £27,500–£60,000. The survey costs you nothing, and after it we commit to a firm price for your specification in writing.
| Type of job | What it usually involves | Guide in Gwynedd |
|---|---|---|
| Rooflight conversion | Rooflights in the existing slope, a new floor, staircase and insulation, where head height already works. | £18,500–£32,000 |
| Dormer conversion | A rear dormer adding headroom and floor space, often with a bedroom and shower room. | £29,500–£55,000 |
| Hip-to-gable or mansard | Larger structural changes to the roof for the maximum usable space. | £46,000–£78,000 |
What moves the price up or down:
- Conversion type: rooflight, dormer, hip-to-gable or mansard
- Steelwork and any strengthening of walls below
- Adding a shower room or en-suite in the roof
- Staircase layout, fire doors and the level of finishes
What do you get?
- Structural calculations and steel beams where needed
- New floor joists strong enough for a habitable room
- Dormer, hip-to-gable or rooflight structure as agreed
- Staircase designed to fit your landing and meet regulations
- Fire doors, mains-linked smoke alarms and a protected escape route
- Electrics, heating and plumbing by qualified trades, with certificates
Homes in Gwynedd
Slate defines much of Gwynedd, from quarrying villages such as Bethesda and Blaenau Ffestiniog with their stone terraces to slate roofs across the county. Bangor and Caernarfon have Victorian and Georgian streets, Anglesey has stone cottages and bungalows, and resorts such as Pwllheli and Barmouth have Victorian terraces and newer bungalows.
Stone and slate homes need breathable lime render and pointing, and slate roofs often need careful repair rather than replacement. Terraces suit loft conversions, and bungalows commonly take extensions and window upgrades.
Eryri (Snowdonia) is among the wettest areas in the UK, and exposed coasts take strong wind and salt, so render and roof details need to be robust.
Do you need permission in Gwynedd?
Each UK nation sets its own consent rules, and Gwynedd is in Wales. What follows is a plain summary; we check the specifics for your property with the council before pricing anything.
In Wales, loft conversions and dormers can be permitted development within volume and position limits (for example, dormers on rear-facing slopes and set back from the eaves). Conservation areas and listed buildings need planning permission.
Building Regulations approval is needed in Wales, and the Party Wall etc. Act 1996 applies to work on shared walls.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
Survey and measure
It starts with a survey at the property, free of charge. We check condition, access and services, ask how you want the finished result to look, and answer any questions you have about a loft conversion.
Price and scope agreed
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Plan and prepare
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Gwynedd property.
On site to finish
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
What you can expect from us
Questions about a loft conversion in Gwynedd
Do I need planning permission in Gwynedd?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. Gwynedd is in Wales, so Wales's rules apply. Many smaller jobs need no planning application, but some still need building control approval. We check what applies to your address before quoting.
Does the Party Wall Act apply to a loft conversion?
The Party Wall etc. Act 1996 applies in England and Wales only, and loft conversions on terraced and semi-detached houses often fall within it, because steel beams are usually set into the shared wall. You must serve notice on the neighbour before work starts, and they can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act. We tell you during the survey whether notices are likely.
Is the price fixed?
Yes, for the specification we agree. Your written quote sets out exactly what is included at a fixed price. It only changes if you ask for something different, or if a problem the survey could not reasonably reveal later needs extra work. In either case we explain the change and confirm it in writing before going ahead.
How much does a loft conversion cost?
A typical dormer loft conversion on a 3-bed semi costs £27,500–£60,000. A simple rooflight conversion costs less, while hip-to-gable and mansard conversions cost more because they change the roof structure. As a rough guide, allow around £800–£1,700 per square metre of new floor plus fixed costs for the staircase, steels and fees. Adding a shower room is the most common extra. We confirm a fixed price after surveying your loft.
Where will the new staircase go?
The new staircase usually sits above the existing stairs, rising from the landing so it uses space that is already circulation. Sometimes it needs to come from a small bedroom or box room, which reduces that room's size. Building regulations set rules on headroom, step size and handrails, with some flexibility for lofts. We look at options at the survey and show you how each affects the floor below.
Towns in Gwynedd
Find your town below. Every place listed in Gwynedd is covered for a loft conversion, with the same survey, written quote and fixed-price process.