Part single, part two-storey extensions in Kempston Hardwick
We plan and build part single, part two-storey extensions for homeowners in Kempston Hardwick and nearby. Every project starts with a free visit and a design stage priced in writing before any work begins.
Before you start in Kempston Hardwick, here's what applies.
- Postcode districts
- MK42
- County / area
- Bedfordshire, England
- Price region
- East of England
- Guide price
- £74,000–£102,000 (£2,060–£2,830 per m²)
- Approval route
- It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
- Nearest towns
- Kempston (1.8 miles), Bedford (3.4 miles), Ampthill (4.3 miles)
- Distance to Luton
- about 14.9 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 Kempston Hardwick (MK42) and the places around it, including Kempston (1.8 miles), Bedford (3.4 miles) and Ampthill.
What it costs in Kempston Hardwick
Our guide for the East of England is £2,060–£2,830 per m² including VAT. On a project with a 6 m × 4 m ground floor and a first floor over half of it (36 m² in total), that puts a part single, part two-storey extension in Kempston Hardwick at roughly £74,000–£102,000. Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.
| Spec | Per m² | A 6 m × 4 m ground floor and a first floor over half of it (36 m² in total) |
|---|---|---|
| Essential | £1,900–£2,610 per m² | £68,000–£94,000 |
| Standard | £2,060–£2,830 per m² | £74,000–£102,000 |
| Premium | £2,470–£3,400 per m² | £89,000–£122,500 |
Planning and building regulations in Kempston Hardwick
In England, the extension can only be permitted development if it goes no more than 3 m beyond the original rear wall and stays at least 7 m from the rear boundary, with matching materials and roof pitch. We check the whole design against the rules, including the 50% garden coverage limit. If any part fails, or extends beyond a side wall on two floors, you need planning permission, costing £548 (or £575 for applications made from 8 December 2026).
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 Kempston Hardwick 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 Kempston Hardwick we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Questions about part single, part two-storey extensions in Kempston Hardwick
Who handles building regulations for a project in Kempston Hardwick?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Do I need planning permission for a part single, part two-storey extension in Kempston Hardwick?
Kempston Hardwick is in England, so England planning rules apply. It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
How much does a part single, part two-storey extension cost in Kempston Hardwick?
Our guide for the East of England, which covers Kempston Hardwick, is £2,060–£2,830 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 £74,000–£102,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Can I add roof lights to the single-storey part?
Yes. Roof lights or a lantern over the single-storey part are one of the main reasons to choose this design, as they light the middle of a deep kitchen. In England they count towards the Part L glazing allowance, normally 25% of the new floor area plus windows removed, so we balance them with the rear doors.
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
Other towns near Kempston Hardwick:
Other extensions in Kempston Hardwick
- Rear
- Side
- Wraparound
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Kempston Hardwick · Part single, part two-storey extensions across Bedfordshire
Book a free site visit in Kempston Hardwick and we'll tell you what's possible, what approvals you need and what the design stage would cost.