Dormer loft conversions in Gwynedd and Anglesey

Covering Gwynedd and Anglesey

We cover Gwynedd and Anglesey, including Bangor, Holyhead, Caernarfon and Llangefni, and the towns around them.

Homes in Gwynedd and Anglesey

Welsh homes include long terraces built into hillsides, stone cottages and modern estates, and sloping sites often shape how and where an extension can go.

What does a dormer loft conversion involve?

A dormer loft conversion builds a box-shaped extension out from the rear slope of the roof, creating vertical walls and full head height across most of the new floor. It is the most popular type of loft conversion because it gives the most usable space for the cost.

Planning and building regulations checks under Welsh rules
Steelwork and new floor structure
Dormer frame, roof covering and cladding

What will a dormer loft conversion cost?

Guide prices for dormer loft conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

Dormer loft conversions	Guide price incl. VAT
Rear dormer, bedroom only	£50,000 to £65,000
Full-width dormer with en-suite	£60,000 to £80,000
L-shaped dormer (over rear outrigger)	£65,000 to £90,000

Planning and building rules in Gwynedd and Anglesey

Planning decisions in Wales are made by the local council, using permitted development rules set by the Welsh Government rather than England’s. Building regulations in Wales have their own approved documents, and the Party Wall etc. Act 1996 applies to work on shared walls and boundaries.

Wales has its own loft and roof permitted development rules. Rear dormers within set volume limits are often allowed, but the detail differs from England's, so we confirm the current Welsh limits against your roof before the design is fixed.

What can change the price or programme?

Dormer cheeks close to a shared wall can trigger the Party Wall Act.
L-shaped dormers are common on Victorian terraces with a rear outrigger.

What happens after I enquire?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Dormer loft conversions: common questions

How much does a dormer loft conversion cost?

Typically £50,000 to £80,000 including VAT, and up to around £90,000 for an L-shaped dormer.

Can a dormer include a bathroom?

Yes. The full head height in a dormer makes it the best place for a shower room or en-suite.

Do you work in Gwynedd and Anglesey?

Yes. Gwynedd and Anglesey is within our coverage for dormer loft conversions, along with nearby Bangor and Holyhead.

Dormer loft conversions in nearby towns

Learn more about dormer loft conversions, or see every project we cover in Gwynedd and Anglesey.