Building regulations for two-storey extensions in Gwynedd and Anglesey

What a building regulations application involves

Building regulations approval for a two-storey extension involves preparing technical drawings and a specification that show how the extension meets the rules on structure, fire safety, insulation, ventilation, electrics and drainage, getting them approved and having the work inspected. At the end you receive a completion certificate.

Towns in Gwynedd and Anglesey include Bangor (Gwynedd and Anglesey) (LL57), Holyhead (LL64), Caernarfon (LL54), Llangefni (LL60), Bethesda (LL57) and Pwllheli (LL51). If yours isn't listed, we still cover it.

Fees

Technical drawings and specification are a guide of £1,500–£4,000. The council's building control fee depends on the value of the work; we confirm every fee in writing before the design stage starts.

Rules in Wales

In Wales, building regulations approval follows the Welsh Approved Documents, which differ from England's in places, notably Part L for energy efficiency. Approval comes from the council's building control service or a registered approver. The structure, fire, ventilation and drainage checks are broadly similar, with a completion certificate at the end.

The Party Wall etc. Act 1996 applies in Wales, so notices may be needed for work on or near a shared wall or boundary.

Getting the design right

Full plans and inspections

Full plans approval checks the design before work starts, which we recommend for two-storey extensions. Building control then inspects key stages, such as foundations, damp-proofing, drainage and insulation, before issuing the completion certificate.

How we work in Gwynedd and Anglesey

1. Measure and listen

   A visit to Gwynedd and Anglesey to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.

2. Design and approvals

   We draw the extension and check it against the rules for Wales, then apply for planning permission or a certificate of lawfulness, whichever fits.

3. Detail and price

   Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.

4. Build it

   The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Towns we cover in Gwynedd and Anglesey

• Bangor (Gwynedd and Anglesey)
• Holyhead
• Caernarfon
• Llangefni
• Bethesda
• Pwllheli
• Blaenau Ffestiniog
• Menai Bridge
• Amlwch
• Tywyn

Neighbouring areas

• Building regulations for two-storey extensions in Clwyd
• Building regulations for two-storey extensions in Merseyside
• Building regulations for two-storey extensions in Cheshire
• Building regulations for two-storey extensions in Powys

All extension services in Gwynedd and Anglesey · About building regulations for two-storey extensions