Two-storey extensions for end-of-terrace houses in Gwent

Gwent at a glance

Nation: Wales
Price region: Wales
Postcode areas: CF, NP
Towns covered: 27 listed below, plus surrounding villages
Approval route: Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission.
Site visits: Free, no obligation

What a two-storey extension for an end-of-terrace house involves

A two-storey extension for an end-of-terrace house is a two-floor addition to the open side or the rear of the last house in a row. The side plot is often the best opportunity, because it adds width without taking rear garden. The design has to work with the terrace's roofline and the street, and any corner plot facing a road needs extra care.

The main places we list in Gwent are Newport (Gwent) (NP10), Cwmbran (NP44), Pontypool (NP4), Ebbw Vale (NP23), Caerphilly (CF83) and Risca (NP11). We cover the villages in between too.

Guide price in Wales

Most of the cost of a two-storey extension for an end-of-terrace house is set by its size and specification. For Gwent and the rest of Wales, our guide is £1,890–£2,530 per m² including VAT, so about £79,000–£106,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

Spec	Per m²	Typical project
Essential	£1,740–£2,330 per m²	£73,000–£98,000
Standard	£1,890–£2,530 per m²	£79,000–£106,500
Premium	£2,260–£3,040 per m²	£95,000–£127,500

Rules in Wales

In Wales, a two-storey side extension on an end-of-terrace house can be permitted development if it is at least 10.5 m from the boundary opposite the side wall, set back at least 1 m from the front and adds no more than 50% to the house's width. Narrow side plots and corner sites rarely meet this, so a householder application costing £585 is common.

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).

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

Older walls and foundations

Many terraces are older, with shallow footings and solid walls. Tying a new two-storey extension into them needs a careful structural design and sometimes movement joints, and we check the gable wall and its foundations before the design is fixed.

Continuing the terrace roof

A side extension on an end-of-terrace house usually continues the roofline of the row, so the pitch, eaves height and tiles must match. A small step down in the ridge and a set-back at the front often help the extension read as an addition rather than an extra house.

How we work in Gwent

Visit and first ideas
One of our team visits your house in Gwent, checks the walls, roof and drains, and sketches out options with you.
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.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.

Towns we cover in Gwent

Two-storey extensions for end-of-terrace houses in Gwent: questions

How much does a two-storey extension for an end-of-terrace house cost in Gwent?

In Wales our guide is £1,890–£2,530 per m² including VAT, so about £79,000–£106,500 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Are old terrace foundations strong enough to extend next to?

Usually, but they need checking. Older terraces often have shallow brick footings, and a new two-storey extension sits on deeper, modern foundations alongside them. The structural engineer designs the junction so the two can move slightly without cracking, and we dig trial holes to see what is there before the design is fixed.

Can I build a two-storey side extension on a corner plot?

Often, but it needs planning permission and careful design. Councils protect the openness of corners and the view along the road, so they usually expect a gap to the pavement, a set-back from the front and a side wall with windows rather than a blank wall. We check local guidance and nearby examples first.

Will my end-of-terrace extension look like a new house on the end?

It should not, if it is designed well. A slightly lower ridge, a set-back from the front wall and a different front door position help it read as an extension. Councils often ask for this to avoid an extension that looks like an extra terraced house.

Will I need planning permission in Gwent?

Gwent is in Wales. Can be permitted development in Wales if it is 10.5 m from the side boundary, set back 1 m from the front and doesn't widen the house by more than half; otherwise planning permission.

Neighbouring areas

All extension services in Gwent · About two-storey extensions for end-of-terrace houses