Part single, part two-storey extensions in Clydach

Before you start in Clydach, here's what applies.

Postcode districts: SA6, SA7 and SA8
County / area: Swansea and Neath Port Talbot, 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: Neath (4.3 miles), Swansea (4.7 miles), Briton Ferry (5 miles)
Distance to Swansea: about 4.7 miles
First visit: Free, no obligation

About a part single, part two-storey extension

A part single, part two-storey extension suits you if you want a generous ground floor but only need one extra room upstairs, or if a full two-storey design would affect a neighbour too much. You get design options that test where the two-storey part works best, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.

Around Clydach we also work in Neath, Swansea and Briton Ferry, and across the rest of Swansea and Neath Port Talbot. Postcode districts in and near Clydach: SA6, SA7 and SA8.

What it costs in Clydach

Most of the cost of a part single, part two-storey extension is set by its size and specification. For Clydach and the rest of Wales, our guide is £1,840–£2,530 per m² including VAT, so about £66,000–£91,000 for a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total). Keep a contingency of around 10% for things nobody can see until the ground is opened up.

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 Clydach

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 Clydach homes

The roof junction

Where the single-storey roof meets the two-storey wall you need a sound weathering detail, usually a lead or similar flashing, and enough height for roof lights or a lantern. We set the roof falls and the upstairs window sill heights together so they do not clash.

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

Understand the brief
At your home in Clydach we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Wales before drawing in detail.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about part single, part two-storey extensions in Clydach

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

Our guide for Wales, which covers Clydach, 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.

Do I need planning permission for a part single, part two-storey extension in Clydach?

Clydach is in Wales, so Wales planning rules apply. 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. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Clydach?

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.

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.

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.

Nearby

Nearby towns we cover for part single, part two-storey extensions:

Other extensions in Clydach

All two-storey extension services in Clydach · Part single, part two-storey extensions across Swansea and Neath Port Talbot

Want a figure first? Try our guide price tool, then book a free visit to firm it up.