Costco UK is offering garden room installation services for members in 2026, with fully installed Green Retreats Basebox rooms listed from about £11,000 and installation included in the price. Here is what’s on offer, what extras cost more, and the planning checks to make before you order.
Costco’s UK site lists several installed garden rooms from specialist builders, not just sheds. The main names are:
These prices came from Costco UK listings and may have changed, so check the live page:
A deals site also listed a 4.2m x 3.6m Basebox at £14,549.98, reduced from £16,799.98. That listing is user-submitted and undated, and the site itself says it cannot guarantee accuracy, so treat it as an example. latestdeals
Costco’s listings are clear about the service. For the B2 range, full professional installation is included in the listed price of every building, and installation is carried out by Green Retreats’ own teams and never outsourced. Another listing says installation takes as little as 1-3 days and that planning permission is rarely required. www.costco.co.uk +3
Delivery matters too. For premium garden rooms, the price includes free delivery in Band 1, and extra charges apply outside of this area. Check the delivery map for your postcode. costco
The Basebox listings highlight Pilkington K Optiwhite extra-clear double glazing on all windows and doors, and one deal page mentions weather-resistant cladding and steel-reinforced uPVC doors and windows in a graphite woodgrain finish. costcolatestdeals
For the Soho range, Outdoor Modular Spaces lists C24 structural timber, NICEIC certified installation, additional sockets and switches, and Cat6 broadband connectivity from your house. Foundations are specified following site inspection. costcocostco
This is where budgets stretch. Costco says you can personalise your room with optional oak laminate flooring, internal electrics, foundations, air-conditioning, decorative side panels and upgraded cladding styles, but these are directly purchased through Green Retreats. Ask for a full itemised quote before you commit, so you know the total cost with electrics and groundwork included. costcocostco
Costco’s listings say planning permission is rarely or generally not needed, and the B2 range is described as permitted development friendly. But one product page has a “planning permission required” field, so don’t assume. Rules depend on size, height, use, distance from boundaries, and whether your home is in a conservation area or listed. Check with your local council or a planning professional before you order. costco
For the Green Retreats rooms, Costco’s pages say to email costco@greenretreats.co.uk or call 01296 328260. Green Retreats says it has operated since 2005 and is rated 5 stars on Trustpilot by its customers. That’s the company’s own claim, so read independent reviews as well. Garden Rooms +2
If you want something smaller, Costco also offers a Premium Installation Service on selected sheds and structures. One listing warns that if preparation steps aren’t completed before the agreed date, Costco will not be liable for any revisit charges if installation can’t be completed. Read the site-prep requirements carefully. costcocostco
Costco UK’s installed garden rooms are a straightforward way to add a home office, gym, or studio, with prices from about £11,000 and professional installation included. But the headline price isn’t the whole cost, so get an itemised quote, check planning rules, and compare before you commit.
This article is general information, not planning or financial advice. Prices, availability, and terms change; confirm details with Costco UK, the installer, and your local council.