Both are hugely popular in North London, especially for families who love their street and want more room without moving. At Kev Construct we build both across Edgware, Barnet, Enfield and Harrow, so here is an honest comparison.
What is a rear extension?
A rear extension extends the back of your house into the garden. It is the classic way to create a large kitchen-diner or an open family room, and it usually gives you the most extra floor space for the money. Because it faces the garden, you can add big glazed doors and rooflights for plenty of natural light.
Many single-storey rear extensions fall within permitted development limits, which can make the process simpler. You do trade some garden for indoor space, so it suits homes with a decent-sized plot.
What is a side-return extension?
A side-return extension fills the narrow strip of land that runs alongside the back of many Victorian and Edwardian terraces. That alley is often wasted space, so building into it can transform a cramped galley kitchen into a wide, bright room without losing much garden at all.
Side-returns are a favourite for period homes because they square off an awkward layout and let light flood in through a glazed roof. They are a little more expensive per square metre because of the detailed work around the existing structure, but the transformation is often dramatic.
What are the pros and cons of each?
In short, choose a rear extension when you want the largest possible room and have the garden to spare. Choose a side-return when your kitchen feels narrow and dark, or when you want to keep as much garden as you can. Many homes combine both in a wraparound extension for the best of each.
How long do they take and what should you plan for?
Most single-storey rear and side-return extensions take around 8-12 weeks on site, weather and materials permitting. Whichever you choose, remember that building regulations apply, and the Party Wall Act often comes into play with a side-return because you are building right up to a shared boundary.
John runs our sites, with Dan and Niko on the tools, so you always have a clear point of contact. Our Checkatrade rating of 9.67/10 from verified reviews shows how seriously we take a tidy, well-managed job.
Frequently asked questions
Is a side-return extension worth it?
For many terraced homes, yes. It turns a wasted alley into usable width, creating a bright, open kitchen while keeping most of the garden.
Which is cheaper, a rear or side-return extension?
A rear extension often gives more space for the money, with a 2026 guide of £50,000-£90,000. A side-return guide is £55,000-£95,000 due to the detailed work involved.
Can I combine a rear and side-return extension?
Yes. A wraparound extension does both at once, creating a large L-shaped room. It costs more but delivers the biggest transformation.
Not sure which is right for your home? Compare options on our full house extensions service and request a free estimate. Marian will give you a clear, itemised quote with no hidden fees.
