Building · Leeds
Side Extension Builders Leeds
Turning a wasted side passage or driveway strip into real, usable floor space.
5.0 / 5 · 21 Google reviewsFree, no-obligation quotesFully insured

The strip down the side of a house is usually the most wasted land on the plot — wide enough for bins and a bike, not much else. A side extension turns it into a proper room: a wider kitchen, a utility, a downstairs shower room, or a home office with its own door. With 20 years' experience, CLM Projects builds side extensions and side returns across Leeds that match the existing brickwork and roofline closely enough that people stop noticing where the old house ends. One experienced team takes it from drawings and planning support through groundworks, steels, brickwork, roofing and glazing to a watertight handover, built properly throughout. We coordinate Building Regulations, prepare Party Wall notices where the build runs along a boundary, and keep the site clean and respectful. Fully insured and Leeds-based. Start with a free, no-obligation quote.
What's Included
Our Side Extensions Service
- Architectural drawings & planning support
- Structural calculations and steel beams where the existing wall is opened up
- Groundworks & foundations, including building close to the boundary
- Party Wall notices prepared where required
- Brickwork and blockwork matched to your existing home
- Roofing tied into the existing roofline — pitched, flat or rooflit
- Glazing, external doors and rooflights
- First & second fix (electrics and plumbing coordinated)
- Plastering, flooring and decorative finish
- Building Regulations coordination and sign-off
Our Work
Building Work by CLM Projects

Glazed Roof Lantern Living Space
Building
Open-Plan Kitchen Extension
BuildingWhy CLM Projects
What Our Building Customers Say
Real, verified Google reviews
“Great company — built my extension years ago and recently a garage conversion into an office, plus other building work. Respectful and quality finish, I highly recommend.”
“Scott… has completed the groundworks and drainage for my wrap-around side/rear extension. Scott was professional from start to finish, he has great communication, and exceeded my expectations. He turned up everyday, rain or…”
“Great guys to work with, highly skilled and people you can trust to do work properly and leave to it. I would highly recommend to anyone wanting quality service.”
How We Work
The CLM Process
Survey & written quote
We visit, measure and photograph the job, then send a clear written quote with exactly what's included.
A planned start date
Once you accept, we book your start date, order materials and handle drawings or building regs where needed.
Staged payments
A deposit to book, then agreed stages as the work progresses. Anything extra is priced and agreed with you first.
Sign-off & guarantee
We walk through the finished work with you, sort any snags, and our workmanship is guaranteed.
Why CLM Projects
- CLM Projects Leeds Ltd, a registered company
- Fully insured (public liability)
- Written quotes, agreed before we start
- Staged payments, extras agreed first
- Workmanship guaranteed
- 20 years in the trade across Leeds
FAQs
Side Extensions — Your Questions
How narrow is too narrow for a side extension?
It depends what you want the space to do rather than on one minimum figure. A narrow side return added to an existing kitchen can transform it, while a standalone room needs more width to be worth having. We measure the side, look at where the drains and the boundary sit, and tell you straight whether it earns its cost.
Do I need planning permission for a side extension in Leeds?
Side extensions are treated more strictly than rear ones under permitted development — width and height are both limited relative to the original house, and the rules differ again on a corner plot or in a conservation area. It is always subject to your specific property, so we confirm the position with Leeds City Council and handle the drawings and any application.
Will the new brickwork match the rest of the house?
That is the detail that decides whether a side extension looks right, because it sits in full view from the street. We match brick, bond and mortar colour as closely as the original allows and tell you honestly where a perfect match is not achievable — weathered brick from decades ago rarely has an exact modern equivalent.
Can I still get to the back garden?
Only if the design keeps a way through. Some side extensions leave a passage or an internal door to the garden, others give that up for the extra width. It is a decision worth making deliberately at drawing stage rather than discovering after the walls are up.
What about the drains running down the side?
There is almost always something under a side passage — a gully, an inspection chamber, or a shared drain. It gets located before the foundations are designed, and building over or diverting a drain is a Building Regulations matter we coordinate rather than something to find halfway through.
Is a side extension cheaper than a rear one?
Not automatically. It is usually smaller, but building tight to a boundary brings its own costs — restricted access, Party Wall notices, sometimes deeper foundations near a drain. Your quote reflects the actual plot rather than a rate per square metre.
Side Extensions Across the Region
Leeds-based and covering the wider region — click your area, or call us to check we reach you.
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Get a Free Side Extensions Quote in Leeds
Tell us about your project and we'll come back with a clear, no-obligation quote. Prefer to talk? Call or WhatsApp 07726 290864.
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Free, no-obligation written quotes from CLM Projects Leeds Ltd. Fully insured, workmanship guaranteed, 20 years in the trade.
