A rear extension is one of the most popular ways to add space and value to your home. Whether you're dreaming of a spacious open-plan kitchen, a family room flooded with natural light, or simply a larger living area, extending the back of your property can transform the way you use your home.
At PMD, we've completed hundreds of rear extensions across Brentwood, Shenfield, Hutton, and the wider Essex area over the past 30 years. Here's our guide to getting your project off the ground.
Do You Need Planning Permission?
In many cases, a single-storey rear extension can be built under Permitted Development rights, meaning you won't need formal planning permission. However, there are limits on size, height, and proximity to boundaries. For a single-storey rear extension, the limit is typically 3 metres for semi-detached houses and 4 metres for detached houses (or 6m and 8m under the Prior Approval process).
Double-storey rear extensions almost always require a full planning application. Your architect will advise on the specifics for your property, and PMD works closely with several excellent local architects we can recommend.
Appointing an Architect
The first step in any extension project is to employ an architect to produce your drawings. These drawings need to be submitted to the Council's Planning Department for approval. A qualified architect will also provide preliminary budgeting based on the square footage of your extension, although the final costs will depend on the finishes you select.
Understanding the Build Timeline
Once your plans are approved, you'll need Building Regulations and Structural Engineers' drawings. These take an additional 6–8 weeks to prepare and approve. After that, PMD will provide a fully detailed, itemised quote — typically within 4 weeks.
A typical single-storey rear extension takes 12–16 weeks to build from breaking ground to completion. A double-storey extension usually takes 16–24 weeks. Weather, the complexity of the design, and the specification of finishes all play a role in the timeline.
Budgeting for Your Extension
Costs vary significantly depending on size, specification, and location. As a rough guide, a high-quality single-storey rear extension in Essex typically costs between £2,500 and £3,500 per square metre for the build, with kitchens, bathrooms, and premium finishes adding to the total.
PMD's quotes are fully transparent and itemised so there are no surprises. We always recommend budgeting a 10–15% contingency for any unforeseen issues.
Key Features to Consider
The most requested features in rear extensions include bi-fold or sliding doors that open onto the garden, glass roof lanterns for overhead natural light, underfloor heating, open-plan kitchen-diners with islands, and vaulted or raised ceilings to create a greater sense of space.
Getting Started
If you're considering a rear extension, the best first step is to get in touch with PMD for an informal, no-obligation conversation. We can visit your property, discuss your ideas, and point you in the right direction with architect recommendations and budget guidance.
Call us on 01277 849664 or use our contact form to start the conversation.