• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
The Garden Room & Annexe Guide Logo
Swift UnlimitedExplore what’s possible
Bespoke Garden RoomsAward-Winning Designs15 Year WarrantyOver 18 years’ experience5 Star ReviewsFully Bespoke or Straight to SiteFriendly, Flexible and Capable Service
The Garden Room & Annexe Guide Logo
Swift UnlimitedExplore what’s possible
Bespoke Garden RoomsAward-Winning Designs15 Year WarrantyOver 18 years’ experience5 Star ReviewsFully Bespoke or Straight to SiteFriendly, Flexible and Capable Service
  • Buyers Guide
        • Introduction
          • What is a garden room?
          • How to buy a garden room
          • Buyers doubts
          • Pre-designed garden rooms
          • Modular garden rooms
        • Rules & Regulations
          • Garden Room Planning Permission Guide
          • Permitted Development Overview
          • Building Regulations
        • Build & Installation
          • Off-site construction
          • Complete on-site builds
          • Garden rooms can be craned in
          • Garden room shell builds
          • Turnkey projects
        • Design Consultations
          • Start designing your garden room
          • What to expect from a design consultation
          • Buying a garden room online
          • Comparing garden room quotes
  • Garden Rooms
        • Examples By Company
          • A to Z of Companies
        • Examples By Use
          • Small Garden Rooms
          • Garden Offices
          • Garden Gyms
          • Art & Creative Studios
          • Soundproof Garden Studios
          • Granny Annexes
          • Explore More Uses
        • Examples by Design Feature
          • With Storage Room
          • With Toilet or Shower Room
          • With Composite Cladding
          • With Canopy
          • With Covered Seating Area
          • With Pitched Roof
  • Garden Living Annexes
        • By Footprint Size
          • Less than 25sqm
          • 25sqm to 35sqm
          • 35sqm to 45sqm
          • 45sqm to 55sqm
          • 55sqm and Above
        • By Room Layout
          • Garden Bedroom
          • Open Plan
          • One Bedroom
          • Two Bedroom
          • 3 and 4 Bedroom
        • Useful Guides
          • What Is an Annexe?
          • How to Build a Granny Annexe
          • Planning and the Caravan Act
          • How Much Does a Granny Annexe Cost?
          • Renting a Granny Annexe
          • Council Tax on a Granny Annexe
          • Granny Pods
          • Annexe Show Sites
          • Ex-Display and Second-Hand Annexes
          • Granny Annexe Projects
  • Price Guides
        • Garden room prices
          • How much does a garden room cost?
          • Garden room price calculator
          • Cheap garden rooms
          • Garden rooms £10,000–£20,000
          • Do garden rooms add value?
        • Annexe prices
          • How much does a granny annexe cost?
          • Council tax on a granny annexe
          • Ex-display and second-hand annexes
          • Renting a granny annexe
        • Paying for it
          • Garden room finance options
          • Protecting your investment
          • Special offers
        • Other ways to buy
          • Second-hand and ex-display
          • Renting a garden office
  • Directory
  • About Us
        • About Us
          • Our Story
          • Work With Us
          • Newsletter
        • Contact Us
          • Our Contact Details
        • Website Policies
          • Revisit Your Cookie Settings
          • Cookie Policy
          • Privacy Policy
          • Acceptable Use Policy
          • Website Terms of Use
  • Your Guide
Garden room project · Swift Unlimited

A home gym and spa retreat by Swift Unlimited

A 13.83m × 4.81m wellness building near the coast in North West England, with a home gym, a spa room around a sunken pool, and glazing wrapping each corner.


Published 23 May 2026 · 5 minute read · Written by The Garden Room & Annexe Guide

The wellness room would not be out of place in a 5 star hotel
Swift Unlimited  13.83m × 4.81m in North West England

There are garden rooms, and then there are buildings that make you question why you’d ever check into a hotel spa again. This project by Swift Unlimited falls firmly into the second category. Located close to the coast in North West England, it’s a bespoke wellness building that houses a fully equipped home gym and a spa retreat complete with sunken pool – a combination that delivers something genuinely exceptional: hotel-quality facilities in a private garden, available every morning before work and every evening after it.

At just under 70 square metres, this is a substantial building. It required planning permission and full Building Regulations approval, both of which Swift Unlimited handled as part of their turnkey service. That scale and that level of ambition would be challenging for many companies to deliver. For Swift Unlimited, it’s the kind of brief they’re built for.

At a glance

  • Size: 13.83m × 4.81m, just under 70sqm, and taller than a standard garden room.
  • Layout: A gym and a spa joined by a glazed internal door, with a shower room and a second small room off the spa.
  • Glazing: A central full-height window, with wide sliding doors wrapping each corner and level thresholds to the paving.
  • Construction: SIPs with a steel frame carrying the roof across the glazed spans, rendered to match the house.
  • Company: Swift Unlimited, who handled planning and Building Regulations, working with the pool specialists, groundworkers and landscapers.

Part of our garden gym guide →

Visit the Garden Annexes website
Uniquely designed
garden rooms
Pre-designed options
from £19,520
Or bespoke — tailored to
your use & garden
No planning permission
in most cases
Based in Brighton & Hove,
building across England
Explore options →
The brief

A brief that started with a vision

The clients knew what they wanted – a dual-purpose wellness building that would cater for serious training on one side and genuine relaxation on the other. Swift Unlimited worked alongside groundworkers, landscapers, pool specialists and architects to bring together all the elements a project of this complexity demands, completing it on time and within budget.

The layout they arrived at is elegantly logical. The building measures 13.83 metres wide by 4.81 metres deep, divided into two rooms. The left-hand space is the home gym, filled with the owner’s choice of fitness equipment. To the right is the spa – a calming, considered retreat built around a sunken pool. Two smaller rooms lead off the spa: a shower room and a second space that, we imagine, functions as either a changing room or plant room. The proportions, flow and adjacency of these spaces reflect careful design thinking, not a standard template.

The floor plan of the garden gym and spa building
The plan: the gym on the left, the spa and its two side rooms on the right.
Glazing

The glazing and the garden connection

Perhaps the most immediately striking feature of this building is its glazing. The façade has a confident, unhurried rhythm: a central full-height window sits as the centrepiece, flanked on either side by rendered wall panels before the glazing wraps around each corner in wide sliding door configurations. The wide sliding doors are deliberately specified to minimise the frame-to-glass ratio – the result is a clean, considered elevation that prioritises the view rather than the structure holding it together.

The glazing has a pleasing rhythm
The garden elevation  full-height glazing at the centre

From inside both the gym and the spa, the garden reads as part of the experience. Training equipment faces the garden. The spa pool is positioned so that the outlook beyond is restful and green. The glazing doesn’t just let light in; it actively frames the space and connects the activities inside to the landscape outside.

The owners chosen gym equipment has views of the garden
The gym  equipment facing the garden

Achieving the seamless threshold between interior and exterior required exactly the kind of careful coordination that Swift Unlimited are known for. The internal flooring, door threshold and exterior paving tiles all sit at the same level, with low-profile thresholds throughout. Getting this right on a project of this scale – with a sunken pool, complex groundworks and a landscaping contractor also on site – required precise planning and close communication. The finished result looks effortless, which is precisely the point.

The doors slide to open the spa onto the garden
Sliding doors  opening the spa onto the garden
Structure

Structure, height and specification

The construction follows Swift Unlimited’s established approach: a multi-layered SIPs (Structural Insulated Panels) envelope with a steel frame integrated to carry the roof load across the substantial glazed spans. The amount of glazing this building incorporates places significant structural demands on the building – demands that the steel frame resolves without compromise to the architectural intent.

The wellness room has a lovely connection with the garden
The wellness room  open to the garden

The building is taller than a standard garden room, offering greater floor-to-ceiling height throughout. That additional height is a practical benefit in the gym, where equipment headroom matters, and a considered aesthetic choice in the spa, where the sense of space adds to the quality of the experience. The extra height was incorporated into the planning approval for the project, with Building Control sign-off completed as part of Swift Unlimited’s turnkey service.

The glazing wraps around the corners of the building
Corner glazing  wrapping round the building

Externally, the SIPs structure has been rendered to complement the finish of the main house – a choice that anchors the building within its setting. A natural timber fascia provides warm relief from the crisp black and white palette, softening the lines and adding texture.

The exterior finishes were chosen to complement the house
Render and timber  to complement the house
The spa

A spa at home

The wellness room, accessed from the gym via an internal glazed door, is the kind of space that would sit naturally within a five-star hotel or high-end spa retreat. Its defining feature is a sunken spa pool, which required both complex groundwork and specialist engineering: deep excavation, significant load management, and the integration of filtration, heating and pumping systems below floor level. Swift Unlimited has considerable experience with exactly these installations, including the less visible but equally critical elements – ventilation systems, heat exchangers and air conditioning units capable of managing the demanding conditions that a spa environment creates, where chemicals, humidity and water exposure are a constant factor.

A glass internal door connects the two main rooms
The glazed internal door  between the gym and the spa
Swift Unlimited engineered the building around the requirements of the sunken pool
The sunken pool

The photographs show a space with all the tranquillity and considered detailing that the brief demanded. Smooth finishes, precise tiling, controlled lighting. It has the feel of a private sanctuary, built to be used daily.

Turnkey service

Turnkey delivery

Projects of this complexity involve a lot of moving parts. What Swift Unlimited bring to a brief like this is the experience to design and build their element of the project to the standard that the wider scheme demands – working alongside the pool specialists, groundworkers and landscapers rather than in isolation from them. The level threshold detail is a good example: achieving the same finished height across internal flooring, door threshold and external paving required careful coordination between Swift and the landscaping team. It worked.

A shower room leads off the spa
The shower room  off the spa
Pricing

Pricing

At current prices, a building of this style, size and specification – with sunken spa pool infrastructure, planning, Building Control and the associated specialist installations – would typically cost in the region of £150,000 to £175,000 including VAT. This figure does not include the cost of the pool itself or associated plant equipment.

Swift Unlimited is currently working on projects across the UK ranging from £60,000 to £420,000, each tailored to the client’s brief and site. Nearly two decades of experience, a commitment to high standards of finish, and a comprehensive turnkey service make them a well-established choice for clients who have a clear vision and want it delivered properly.

Planning something similar?

Learn more about Swift Unlimited

To find out more about Swift Unlimited’s bespoke garden rooms, annexes and extensions, visit www.swiftorg.co.uk. You can contact the team on 01625 875 588 or at support@swiftunlimited.co.uk to discuss your project.

Visit Swift Unlimited More Swift Unlimited projects
More projects like this Garden gyms Gyms with a shower room Gyms with extra ceiling height 30sqm+ garden rooms
Read the guides What garden rooms cost Permitted development Garden room ceiling height

Published 23 May 2026 · Photographs courtesy of Swift Unlimited.

Visit the Garden Spaces website
Visit the Timeless Garden Rooms website
Visit the Garden2Office website
Uniquely designed
garden rooms
Pre-designed options
from £19,520
Or bespoke — tailored to
your use & garden
No planning permission
in most cases
Based in Brighton & Hove,
building across England
Explore options →
Visit the Modern Garden Offices website

Primary Sidebar

Visit the Garden Annexes website to explore their homes in the garden
Visit the Garden Spaces website
Warwick Buildings Warwick Buildings Garden Gyms
Garden Gyms
From £9,500 including VAT, delivery and installation
Insulated for year-round use 21 buildings on show near Southam Flat, pitched & curved roof designs 10-year guarantee Online design & price configurator Made in Warwickshire since 1988 100mm walls, five layers thick
See garden gym options
Visit the Bridge Garden Rooms website
ARK
Bespoke Garden Roomsacross the South East
Bespoke — designed around you Designed for Permitted Development Insulated for year-round use Offices, studios, gyms & more Building regs handled Fully project-managed build Handcrafted quality throughout
Explore our garden rooms →
Excellent ★★★★★Trustpilot
Visit the Modern Garden Rooms website
Uniquely designed
garden rooms
Pre-designed options
from £19,520
Or bespoke — tailored to
your use & garden
No planning permission
in most cases
Based in Brighton & Hove,
building across England
Explore options →
Cosy Garden Rooms
FAST INSTALLATIONS FULLY INSULATED 10 YEAR GUARANTEE
Bespoke Garden Rooms
Get Your FREE Quote
SIPS Garden RoomsBespoke garden rooms
Design
Approvals
Build
Handover
Warm in winter.
Cool in summer.
Insulated panel walls and roof, so it holds its temperature.
Designed around your garden, not picked from a range.
A fixed written price before any work starts.
An office, a studio or a gym, whatever you need it for.
See garden room projects
Crusoe Garden Rooms
Garden Gyms
Garden gyms with room
for the rack and the rower
Your choice of doors Hand-built on site, not prefabricated More than 350 garden rooms built Western Red Cedar as standard Electrical connection included Free site visit, in person or by video Building across the UK from Nottingham
See garden gym options

Bespoke garden annexes

More than a garden room: a complete annexe.

Design, planning, foundations, agreed connections and installation, in one fixed-price quote.

1-bedroom from£85,000
2-bedroom from£130,000
See our granny annexes

The Green Room · 01536 358387

Useful Links

Planning Permission Guides

A to Z of Companies

Garden Rooms

Garden Living Annexes

Garden Room & Annexe Directory

Contact Us

Contact Us

Work with Us

Website Policies

© 2026 The Garden Room & Annexe Guide. All Rights Reserved.
The Garden Room & Annexe Guide is powered by the team at Square Meter Media Limited