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CG Joinery builds bespoke, fully insulated garden rooms in and around Lisburn, used as home offices, gyms, studios and extra living space. Every room is built on site, usually in 3–5 days, with a 10-year warranty. Lisburn is under an hour from our Newry showroom. Whether you need a dedicated home office, a peaceful retreat, a gym, or an extra room for entertaining guests, our insulated garden rooms offer year-round comfort, quick installation, and long-lasting quality.

CG Joinery is a family-run business with over 15 years of experience in construction and joinery. Since 2009, we’ve delivered high-quality, bespoke timber garden rooms across Northern Ireland and the Republic of Ireland, including dozens of successful projects in and around Lisburn.
Our garden rooms are built on-site by a team of fully qualified professionals, ensuring each one meets the highest standards of craftsmanship and durability. Whether your property is in central Lisburn or the surrounding countryside, we’ll work with you to create a bespoke garden building that seamlessly fits your outdoor space.
Garden rooms suit Lisburn homes because they add a usable room quickly, with far less disruption than an extension, and most don’t need planning permission. A garden room offers a cost-effective and versatile solution — ideal for remote working, fitness, creativity, or simply relaxing in your own private space.
Unlike a traditional home extension, garden rooms typically do not require planning permission, are faster to install, and cause minimal disruption to your everyday life. At CG Joinery, we aim to complete most garden rooms in just 2–5 days.
We consist of a group of highly qualified tradesmen and are now very proud specialists in insulated garden rooms, serving all across Ireland.
We aim to have our insulated garden buildings completed within 3-5 days to minimise disruption for you.
Confirm your booking with a deposit, then then make part-payment on day one of installation followed by final payment on completion day. *Finance options now available

We provide a full end-to-end garden room service in Lisburn — including initial consultation, bespoke design, on-site construction, and full aftercare. Our rooms are built to last, with high-quality materials and professional installation from start to finish.
Popular Uses for Garden Rooms in Lisburn

Create valuable additional room without the cost and disruption of a full extension. Our garden rooms provide a comfortable, insulated space perfect for relaxing, entertaining, or giving your family more room to live.

Work from home in a quiet, purpose-built space designed for productivity and comfort. A CG Garden Room helps you separate work and home life while adding value to your property.

Enjoy the convenience of a private workout space just steps from your door. Our garden gyms are built to handle equipment, reduce noise, and provide a motivating environment all year round.

Run your business from a professional, dedicated space at home. Ideal for beauty, hair, therapy, or creative studios, our garden rooms offer privacy, comfort, and a welcoming environment for clients.

Create a calm, safe space tailored to relaxation and sensory needs. Designed with comfort, insulation, and sound control in mind, these rooms provide a peaceful retreat for both children and adults.

Have a unique vision? We design and build fully bespoke garden rooms tailored to your exact needs, style, and space — delivering a one-of-a-kind solution that works perfectly for you.
At CG Joinery, we build every garden room to the same standards you’d expect inside your home. Our team uses premium timber and insulation to ensure a warm, dry space that’s usable throughout the year — even during those cold Lisburn winters.
We work closely with you on every detail — from layout and internal finishes to doors, windows, electrics, and even internet setup. Your garden room will be ready to move into as soon as we hand it over.
Yes. We’ve built garden rooms in and around Lisburn, from central streets to the surrounding countryside. Each one is designed around your garden and built on site by our own qualified team.
Garden rooms start from €15,000. Your price depends on size, glazing, insulation and heating, and how easily materials can reach the garden. We survey the site first and give you a written quote with everything included, so there are no extras added once work starts.
Usually not. Most garden rooms in Northern Ireland fall under permitted development if they’re single storey, behind the house, under 4 m high (2.5 m within 2 m of a boundary) and cover no more than half the garden. We check your property, including any conservation area or listed status, at survey.
Most garden rooms are built on site in 3–5 days. Lisburn is under an hour from our Newry base, so surveys and installation dates are easy to arrange.
Lisburn customers use their garden rooms as home offices, gyms, studios, therapy or beauty rooms, playrooms and extra living space. We plan the layout, power points, lighting and heating around the use you have in mind.
€1500 off all garden rooms if you book in July. Don't miss out!