Two-storey extensions for semi-detached houses in Leeds

Leeds: the key facts for this kind of project.

Postcode districts: LS1, LS2, LS3, LS4, LS9, LS10 and nearby districts
County / area: West Yorkshire, England
Price region: Yorkshire and the Humber
Guide price: £51,500–£69,500 (£1,840–£2,480 per m²)
Approval route: Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission.
Nearest towns: Chapel Allerton (2.3 miles), Morley (4.4 miles), Pudsey (4.6 miles)
First visit: Free, no obligation

About a two-storey extension for a semi-detached house

This service suits you if you own a semi-detached house and want to add bedrooms and living space without moving. On a semi, the main questions are which side to build on and how to treat the attached neighbour. You get a survey, design options, the approvals your nation needs and the build, carried out by vetted teams working under S&K.

We cover Leeds (LS1, LS2, LS3, LS4, LS9, LS10 and nearby districts) and the places around it, including Chapel Allerton (2.3 miles), Morley (4.4 miles) and Pudsey.

What it costs in Leeds

Expect a two-storey extension for a semi-detached house in Leeds to land somewhere around £51,500–£69,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Our Yorkshire and the Humber guide rate is £1,840–£2,480 per m², including VAT. 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	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,690–£2,290 per m²	£47,500–£64,000
Standard	£1,840–£2,480 per m²	£51,500–£69,500
Premium	£2,210–£2,980 per m²	£62,000–£83,500

Planning and building regulations in Leeds

In England, a two-storey rear extension on a semi can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary, with matching materials and roof pitch. A two-storey side or wraparound extension always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). Protected areas such as conservation areas exclude two-storey rear permitted development.

Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

Design points for Leeds homes

The attached neighbour's light

A two-storey rear extension next to the party wall can take light from the neighbour's rear windows. Councils often use a 45-degree test, so the first floor may need to be shorter than the ground floor or set in from the shared boundary.

Keeping the pair balanced

Semis are designed as matching pairs, and a side extension changes that balance. Setting the side extension back from the front wall and keeping its ridge lower helps the pair still read as a pair, which councils' design guides commonly ask for.

How we'd run your project

Measure and listen
A visit to Leeds to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Questions about two-storey extensions for semi-detached houses in Leeds

How much does a two-storey extension for a semi-detached house cost in Leeds?

Our guide for Yorkshire and the Humber, which covers Leeds, is £1,840–£2,480 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £51,500–£69,500. 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 Leeds?

We cover Leeds (LS1, LS2, LS3, LS4, LS9, LS10 and nearby districts) and nearby places including Chapel Allerton, Morley and Pudsey, plus the rest of West Yorkshire. The first site visit is free.

Do I need planning permission for a two-storey extension for a semi-detached house in Leeds?

Leeds is in England, so England planning rules apply. Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Will a side extension make my semi look like a terrace?

It can if it fills the whole gap to the boundary at first floor and the neighbour does the same. Many councils ask for a first-floor gap to the side boundary or a set-back for this reason. We design the extension to keep the semi reading as one of a pair.

What if my neighbour has already extended?

That often helps. An existing extension next door can reduce the effect of yours on their light, and may show what the council accepts on your street. It can also mean building alongside their wall, so we check its position, foundations and any windows facing your plot at the survey.

Nearby

We also cover places near Leeds, including:

Other extensions in Leeds

All two-storey extension services in Leeds · Two-storey extensions for semi-detached houses across West Yorkshire

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Leeds.