How Long Does a Home Extension Take?

A well-run single-storey extension typically takes around six months from first design sketch to finished build in the UK — about a month of design, up to eight weeks for planning, then 10 to 16 weeks on site.

"How long will it actually take?" It's one of the first questions every homeowner asks — and one of the most important to get right. Because a realistic timeline is the difference between a smooth project and months of frustration.

Let's map out how a well-run extension can go from idea to reality in around six months.

Setting Realistic Expectations

First, a reality check: six months is achievable for a typical extension, but only with good planning and no major surprises. Some projects move faster; complex ones take longer. The key is knowing the steps so nothing catches you off guard.

The Typical Timeline

Here's how the six months tends to break down:

Month 1 — Design and brief. We get to know how you live, develop the design, and refine it until it's right. Changes here cost nothing, so this is time well spent.

Month 2 — Planning and approvals. If you need planning permission, this is where the 8-week clock starts. We prepare and submit everything while you carry on with life.

Month 3 — Technical drawings and builder selection. Detailed building regulations drawings get prepared, and you choose your builder. We help you compare quotes properly — not just on price.

Months 4–6 — Construction. The build itself. For a typical single-storey extension, expect 10–16 weeks on site, depending on size and complexity.

What Can Slow Things Down

Being honest about the bumps:

• Planning delays or refusals
• Slow decision-making (your choices keep things moving)
• Bad weather affecting groundwork
• Late changes to the design
• Supply delays on materials or fittings

Most of these are manageable with good planning and quick decisions.

How to Keep Things on Track

• Make decisions promptly. Indecision is the biggest hidden delay.
• Lock the design early. Resist the urge to keep tweaking.
• Choose a reliable builder. Cheapest isn't fastest.
• Trust the process. A good team has done this many times before.

The Payoff

Six months might feel like a long time when you start — but it passes quickly, and the result is a home that works beautifully for years to come. The families who plan well and decide quickly are the ones sipping coffee in their new kitchen right on schedule.

Let's Get Started

Dreaming of a finished extension by this time next year? The sooner you start, the sooner you're there. Let's map out your timeline together.