One of the most common questions we receive at J & L Building & Design is: "How much will my extension cost?" It's a fair question, and one that deserves a straight answer rather than a vague range. This guide explains the main cost factors for house extensions in Macclesfield and the wider Cheshire area, based on our 30+ years of experience building extensions across the region.
What Affects the Cost of a House Extension?
No two extensions are the same. The price depends on a combination of factors specific to your property and your requirements. The most significant are:
- Size — floor area is the primary cost driver. A larger footprint means more materials, more labour and more time.
- Storeys — a two-storey extension costs more than a single-storey one, but the cost per square metre is often lower because the foundations, roof and scaffolding are shared.
- Specification — the quality of materials, glazing, kitchen or bathroom fittings, flooring and finishes has a substantial effect on the final figure.
- Structural complexity — removing load-bearing walls, installing steel beams (RSJs), underpinning or working on difficult ground conditions adds cost.
- Access — restricted access for plant, deliveries or skips can increase labour time and therefore cost.
- Planning and design fees — if planning permission is required, architect and planning fees are additional to the build cost.
- Location within Cheshire — labour and material costs can vary slightly across the region.
Typical Extension Cost Ranges in Macclesfield (2025)
The following figures are indicative ranges based on current Cheshire market conditions. They are not quotations. Your actual cost will depend on the specific factors above and can only be confirmed after a site visit and detailed specification.
| Extension Type | Typical Range (per m²) | Notes |
|---|---|---|
| Single-storey rear extension | £1,800 – £2,500/m² | Standard specification, no structural complications |
| Single-storey side extension | £1,900 – £2,600/m² | May require planning permission depending on size |
| Two-storey extension | £1,600 – £2,300/m² | Lower per-m² cost; higher total project cost |
| Kitchen extension (open-plan) | £2,000 – £3,000/m² | Includes structural alterations, glazing, utilities |
| Porch / entrance extension | £8,000 – £18,000 | Typical total project cost |
| Garden room / summer house | £15,000 – £40,000+ | Highly specification-dependent |
These figures are based on credible UK industry sources including the RICS Building Cost Information Service and current Cheshire contractor pricing as of 2025. They include labour and materials but typically exclude VAT, professional fees, planning costs and any unforeseen structural work.
What Is and Is Not Included in an Extension Quote
When comparing quotes from builders, it is essential to understand exactly what each quote covers. A J & L quote will clearly set out what is included. Common areas where quotes differ include:
- Groundworks and foundations
- Structural steelwork (RSJs)
- Roof construction and covering
- External brickwork or render
- Windows and external doors
- Internal plastering
- First and second fix electrics
- Plumbing and heating connections
- Flooring
- Decoration
- Building Regulations inspections
Always request an itemised written quote rather than a single lump-sum figure. This makes it far easier to compare quotes fairly and understand what you are paying for.
Planning Permission and Building Regulations Costs
Planning permission is not always required for a house extension — many fall within permitted development rights. However, when planning permission is needed, you should budget for architect or designer fees (typically £1,500–£5,000+ depending on complexity) and Cheshire East Council planning application fees (currently £258 for a householder application as of 2025).
Building Regulations approval is required for virtually all extensions regardless of whether planning permission is needed. Building Control fees vary by project size but are typically £500–£1,500 for a standard extension.
How to Get an Accurate Price for Your Extension
The only reliable way to get an accurate cost for your specific extension is to have a builder visit the property, understand your requirements in detail, and provide a written, itemised quotation. Be cautious of online calculators or instant quotes — they cannot account for the specific conditions of your property.
At J & L Building & Design, we provide free, no-obligation quotes following a site visit. We have been building extensions across Macclesfield, Wilmslow, Alderley Edge, Prestbury, Bollington and the wider Cheshire area for over 30 years.
Frequently Asked Questions
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