Welshpool · Powys

First-floor extensions in Welshpool

Our first-floor extensions service in Welshpool covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.

The basics for Welshpool at a glance.

Postcode districts
SY15, SY21 and SY22
County / area
Powys, Wales
Price region
Wales
Guide price
£23,000–£33,500 (£1,660–£2,390 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
Newtown (11.8 miles), Llanidloes (22 miles), Knighton (22.3 miles)
Distance to Newtown
about 11.8 miles
First visit
Free, no obligation

About a first-floor extension

A first-floor extension suits you if your house already has a single-storey extension and you need more space upstairs. You get a structural check of the existing walls and foundations, a design that ties the new floor into the house, the approvals your nation needs, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

Around Welshpool we also work in Newtown, Llanidloes and Knighton, and across the rest of Powys. Postcode districts in and near Welshpool: SY15, SY21 and SY22.

What it costs in Welshpool

Guide prices for first-floor extensions in Wales are around £1,660–£2,390 per m² of new floor space, including VAT. For a typical project with 4 m × 3.5 m of new first-floor space (14 m²), that's roughly £23,000–£33,500. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

SpecPer m²4 m × 3.5 m of new first-floor space (14 m²)
Essential£1,520–£2,200 per m²£21,500–£31,000
Standard£1,660–£2,390 per m²£23,000–£33,500
Premium£1,990–£2,870 per m²£28,000–£40,000

Planning and building regulations in Welshpool

In Wales, a first floor over a rear extension can be permitted development if it goes no more than 3 m beyond the original rear wall and stays at least 10.5 m from the rear boundary, with the ground floor within 4 m. Over a side extension, the 10.5 m, 1 m set-back and 50% width tests apply. Otherwise 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 Welshpool homes

Can the existing structure take it?

Many single-storey extensions were built with foundations, walls and lintels sized for one storey. We find out what is there with trial holes and, where available, the original building control drawings. The engineer then decides whether to reuse, strengthen or rebuild parts of the structure.

Replacing the flat roof

The existing roof usually comes off and is replaced by a new first-floor structure. The room below is exposed for a short time, so we plan temporary weatherproofing and sequence the work to keep the kitchen or living room usable for as long as possible.

How we'd run your project

  1. Visit and first ideas

    One of our team visits your house in Welshpool, checks the walls, roof and drains, and sketches out options with you.

  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. Structure and building control

    A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.

  4. Build and hand over

    We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about first-floor extensions in Welshpool

How much does a first-floor extension cost in Welshpool?

Our guide for Wales, which covers Welshpool, is £1,660–£2,390 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £23,000–£33,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Welshpool?

We cover Welshpool (SY15, SY21 and SY22) and nearby places including Newtown, Llanidloes and Knighton, plus the rest of Powys. The first site visit is free.

Who handles building regulations for a project in Welshpool?

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 I build on top of my existing single-storey extension?

Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.

What happens to the room below while the first floor is built?

The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.

Nearby

Close to Welshpool? We work across the area, including:

Other extensions in Welshpool

All two-storey extension services in Welshpool · First-floor extensions across Powys

Book a free site visit in Welshpool and we'll tell you what's possible, what approvals you need and what the design stage would cost.

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