How Much Does a Home Extension Cost in Guildford? 2025 Local Pricing Guide
Home extensions remain one of the most popular building projects across Guildford in 2025. With strong property prices, excellent transport links and high demand for family homes, many homeowners are choosing to extend their existing properties rather than move.
Whether you live in Burpham, Merrow, Onslow Village, Worplesdon or central Guildford, understanding local extension costs will help you plan your project realistically and avoid unexpected expenses. This guide explains how much a home extension costs in Guildford, what affects pricing, and what to consider before you start building.
Average Home Extension Costs in Guildford (2025)
Extension costs vary depending on size, design, materials and structural complexity. Below are typical price ranges for Guildford and surrounding areas.
Single-Storey Extensions
£2,000 – £2,800 per m²
Single-storey extensions are ideal for:
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- Kitchen extensions
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- Dining and family rooms
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- Open-plan living spaces
They are particularly popular in Guildford areas with larger gardens, such as Merrow and Worplesdon.
Double-Storey Extensions
£2,400 – £3,500 per m²
Double-storey extensions offer excellent value by increasing living space on both floors while sharing foundations and roofing.
Common uses include:
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- Larger kitchens below
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- Additional bedrooms upstairs
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- Extra bathrooms or en-suites
These are often chosen by growing families who want to stay within Guildford’s school catchment areas.
Side & Rear Extensions
£35,000 – £70,000+
Side and rear extensions depend heavily on:
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- Available access
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- Structural alterations required
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- Roof design and glazing
Many semi-detached properties in Guildford are well suited to this type of extension.
Wrap-Around Extensions
£60,000 – £110,000+
Wrap-around extensions combine side and rear extensions to create a complete ground-floor transformation. They are ideal for open-plan kitchen-living spaces and are increasingly popular in higher-value Guildford homes.
What Affects the Cost of an Extension in Guildford?
1. Property Type & Age
Guildford has a wide range of property styles, including:
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- Period and character homes
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- 1930s family houses
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- Modern developments
Older homes may require additional structural work, insulation upgrades or rewiring, which can increase costs.
2. Design & Finish Level
Higher-end specifications increase budgets, including:
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- Bifold or sliding doors
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- Roof lanterns and skylights
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- Bespoke kitchens
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- Underfloor heating
Guildford homeowners often opt for premium finishes, which should be factored into early cost planning.
3. Ground Conditions
Groundworks costs can vary depending on soil type and drainage. Larger extensions may require deeper foundations, particularly on sloping plots.
4. Planning Permission & Regulations
While many extensions fall under Permitted Development, planning permission may be required if:
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- Size limits are exceeded
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- It’s a double-storey extension
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- The property is in a conservation area
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- The design significantly alters the appearance of the home
Building Regulations approval is always required, regardless of planning permission.
Do You Need Planning Permission for an Extension in Guildford?
Many homeowners are surprised to learn that planning permission is not always needed. Under Permitted Development rules, you may be able to extend:
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- Up to 3–4 metres for terraced or semi-detached homes
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- Up to 8 metres for detached homes (subject to conditions)
However, restrictions apply, especially for homes near conservation areas or listed buildings. Professional advice is recommended before starting work.
How Long Does a Home Extension Take to Build?
Typical build times include:
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- Small single-storey extension: 8–12 weeks
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- Medium extension: 12–18 weeks
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- Large or double-storey extension: 16–24+ weeks
Design, approvals and structural complexity can extend timelines, so early planning is essential.
Why Extensions Are So Popular in Guildford
Home extensions continue to rise in popularity across Guildford because they:
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- Add valuable living space
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- Increase property value
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- Allow families to stay in desirable areas
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- Improve layouts for modern living
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- Avoid the high cost and disruption of moving
With Guildford’s strong housing market, a well-designed extension is often seen as a long-term investment.
How Much Value Can an Extension Add?
A professionally built extension can add 10–25% to a property’s value, depending on size, quality and location. In high-demand Guildford areas, the return can be particularly strong when extensions improve kitchens, add bedrooms or create open-plan layouts.
Final Thoughts
A home extension is a significant investment, but when planned and built correctly it can transform how you live and add substantial value to your Guildford property. Understanding local extension costs in Guildford allows you to budget accurately and make informed decisions from the outset.
Working with an experienced local builder ensures your extension is compliant, well-designed and completed to a high standard — giving you a home that works better for years to come.