Part single, part two-storey extensions in Menai Bridge

Useful details for planning a part single, part two-storey extension in Menai Bridge.

Postcode districts: LL56 and LL59
County / area: Gwynedd and Anglesey, Wales
Price region: Wales
Guide price: £66,000–£91,000 (£1,840–£2,530 per m²)
Approval route: It may be permitted development if the ground floor goes no more than 4 m and the first floor no more than 3 m beyond the original rear wall, with the first floor 10.5 m from the rear boundary.
Nearest towns: Bangor (Gwynedd and Anglesey) (1.7 miles), Bethesda (5.6 miles), Llangefni (6.2 miles)
Distance to Bangor (Gwynedd and Anglesey): about 1.7 miles
First visit: Free, no obligation

About a part single, part two-storey extension

A part single, part two-storey extension is an extension where the ground floor is wider or deeper than the floor above, so only part of it rises to two storeys. It usually gives a large kitchen or living area with roof lights below and one bedroom or bathroom above. It is often a good way to add space while limiting the effect on neighbours.

We cover Menai Bridge (LL56 and LL59) and the places around it, including Bangor (Gwynedd and Anglesey) (1.7 miles), Bethesda (5.6 miles) and Llangefni.

What it costs in Menai Bridge

In Wales, which includes Menai Bridge, we'd expect a part single, part two-storey extension to cost around £66,000–£91,000 for a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total), or £1,840–£2,530 per m² including VAT. The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	A 6 m × 4 m ground floor and a first floor over half of it (36 m² in total)
Essential	£1,690–£2,330 per m²	£61,000–£84,000
Standard	£1,840–£2,530 per m²	£66,000–£91,000
Premium	£2,210–£3,040 per m²	£79,500–£109,500

Planning and building regulations in Menai Bridge

In Wales, a part two-storey rear extension can be permitted development if the first floor goes no more than 3 m and the ground floor no more than 4 m beyond the original rear wall, with the first floor at least 10.5 m from the rear boundary. Conservation areas and other protected areas are excluded. If the design falls outside these limits, a householder application costs £585.

Approval in Wales: Householder planning application: £585. Councils normally decide householder applications within 8 weeks.

Building regulations: Building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency).

Design points for Menai Bridge homes

Where to put the two-storey part

The two-storey section usually works best away from the closest neighbour, with the single-storey part on that boundary side. We test a few positions against neighbours' windows, the upstairs layout and the roof shape before choosing the one to take forward.

Structure at the step

The first-floor wall above often sits over the new open-plan space, so it needs a steel beam or frame to carry it. Loads come down at different points than in a full two-storey design, and the engineer sizes the foundations to suit each part.

How we'd run your project

Visit and first ideas
One of our team visits your house in Menai Bridge, checks the walls, roof and drains, and sketches out options with you.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Menai Bridge.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about part single, part two-storey extensions in Menai Bridge

How much does a part single, part two-storey extension cost in Menai Bridge?

Our guide for Wales, which covers Menai Bridge, is £1,840–£2,530 per m² including VAT. A typical project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) comes to about £66,000–£91,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Who handles building regulations for a project in Menai Bridge?

We handle it as part of the project. What's needed in Wales: building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency). We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

Which postcodes do you cover around Menai Bridge?

We cover Menai Bridge (LL56 and LL59) and nearby places including Bangor (Gwynedd and Anglesey), Bethesda and Llangefni, plus the rest of Gwynedd and Anglesey. The first site visit is free.

Which side should the two-storey part go on?

Usually the side furthest from the nearest neighbour's windows, so the single-storey part sits nearest them and keeps their light. Other factors are where the stairs land upstairs, which room needs the extra space and where drains run. We sketch options at the design stage and explain which is most likely to be approved.

Can the single-storey part be deeper than the two-storey part?

With planning permission, yes, and that is often the point of the design: the ground floor projects further into the garden while the first floor stays back from neighbours. Under permitted development, the depth limits for extensions of more than one storey can apply to the whole extension, so we confirm which route applies before drawings are finalised.

Nearby

The same service in neighbouring towns:

Other extensions in Menai Bridge

All two-storey extension services in Menai Bridge · Part single, part two-storey extensions across Gwynedd and Anglesey

Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.