How Long Does It Take To Build An Extension?

Adding an extension to your home is an excellent way to increase space and boost property value. However, one of the most common questions homeowners ask is: How long does it take to build an extension? The answer depends on various factors, including the type of extension, construction method, planning permissions, and site conditions.

Factors Affecting Extension Build Time

Several key elements influence the duration of an extension project:

1. Type of Extension

• Single-storey extension – Generally takes 6–12 weeks to complete.
• Double-storey extension – Can take 10–16 weeks, depending on complexity.
• Modular extension – Prefabricated in a factory and installed on-site in as little as 2–4 weeks.
• Wraparound extension – More complex, requiring 12–20 weeks.

2. Planning Permission & Approvals

• Permitted Development: If your extension meets criteria under Permitted Development rights, you can avoid lengthy planning approvals.
• Planning Permission: If required, obtaining approval can take 8–13 weeks.
• Building Regulations: Even if you don’t need planning permission, you must comply with UK Building Regulations, adding time for inspections.

3. Site Preparation & Groundworks

Before construction begins, groundwork preparation is crucial. This includes clearing obstacles, digging foundations, and laying drainage systems. This stage can take 1–3 weeks, depending on site conditions.

4. Construction Method

• Traditional Brick & Mortar: Takes longer due to on-site construction, typically 10–20 weeks.
• Modular Construction: Faster alternative, where sections are built off-site and installed within 2–4 weeks.
• Timber Frame Construction: Quicker than traditional methods, often completed in 8–12 weeks.

5. Weather Conditions

Adverse weather can cause delays, especially for traditional construction projects reliant on outdoor labour. Modular extensions are less affected as they are built in controlled environments.

How Long Do Different Stages of an Extension Take?

Stage	Traditional Build Time	Modular Build Time
Planning & Approvals	8–13 weeks	2–6 weeks
Groundworks	2–4 weeks	1–2 weeks
Structure Build	6–12 weeks	2–4 weeks
Roofing & Windows	2–4 weeks	1–2 weeks
Internal Finishes	4–8 weeks	1–3 weeks
Total Duration	20–40 weeks	6–12 weeks

Comparing Extension Build Costs in Different Locations

The cost of building an extension varies depending on location, material costs, and labour charges. Here’s a comparison of average extension costs per square metre in Milton Keynes, Cambridge, London, Harpenden, and Market Harborough.

Location	Average Cost per sqm
Milton Keynes	£2,000 – £2,500
Cambridge	£2,200 – £2,800
London	£3,000 – £4,500
Harpenden	£2,800 – £3,500
Market Harborough	£2,000 – £2,600

Factors Affecting Costs

• Labour costs – Higher in London and surrounding areas.
• Material prices – Vary based on availability and supplier rates.
• Property type – Terraced houses with limited access may incur additional costs.
• Construction method – Modular builds are often more cost-effective than traditional methods.

How to Speed Up Your Extension Build

1. Choose a Modular Extension – This drastically cuts build time and minimises on-site disruption.
2. Get Planning Sorted Early – If planning permission is needed, apply as soon as possible.
3. Work with Experienced Builders – Vergolus has over 30 years of experience in fast, high-quality extensions.
4. Ensure Site Preparation is Done Efficiently – Clearing and preparing the site beforehand can prevent delays.
5. Opt for a Turnkey Solution – Our all-in-one service includes design, planning, structural work, and finishing touches, making the process seamless.

FAQs

1. What is the fastest type of extension to build?

A modular extension is the quickest, often completed in 2–4 weeks once on-site.

2. Does bad weather affect build times?

Yes, for traditional builds. Modular extensions are factory-made and avoid weather-related delays.

3. Can I live in my home during construction?

For smaller or modular extensions, it’s possible. Larger projects may require temporary relocation.

4. How long does planning permission take?

Usually 8–13 weeks, but Permitted Development rules can speed things up.

5. Does a kitchen extension take longer to build?

Yes, due to plumbing and electrical work, adding 2–4 extra weeks.

6. Can I extend a terraced house quickly?

Yes, modular systems work well for terraced houses, completing in under 4 weeks.

7. How do I reduce disruption during the build?

Using a turnkey service like Vergolus, where everything from design to finishing is handled professionally.

8. Do double-storey extensions take twice as long?

Not necessarily. With efficient planning, a double-storey extension can take only a few weeks longer than a single-storey build.

9. How much does an extension cost per sqm?

On average, £2,250 per sqm, but modular builds can be more cost-effective.

10. Will my extension add value to my home?

Yes! A well-built extension can increase property value by 10–20%, making it a smart investment.

A Faster, More Efficient Solution with Reduced Disruption

The time it takes to build an extension depends on various factors, including planning approvals, construction methods, and project complexity. Traditional extensions can take several months, while modular extensions can be completed in just a few weeks.

Choosing a modular extension offers a faster, more efficient solution with reduced disruption, making it ideal for busy homeowners who want a high-quality build without lengthy construction times. With the latest advancements in modular construction technology, you no longer have to worry about the inconvenience of long build times and excessive labour costs. Instead, you can enjoy a stress-free experience with a professionally built extension that is durable, stylish, and built to last. At Vergolus, we provide a seamless, turnkey extension service that ensures your new space is designed, approved, and built with minimal hassle. Whether you need extra living space, a larger kitchen, or a home office, we have a cost-effective and time-efficient solution that suits your needs. If you’re considering an extension but worried about how long it will take, contact us today for a consultation. Our expert team will help you plan and execute your project efficiently, so you can enjoy your extended home sooner than you think!