A PLACE TO FOCUS
Home offices ↗
Create a dedicated workspace away from household distractions. Plan desk space, sockets, network connections and daylight around your working day.
10sqm from £14,000+ Guide price including VAT
TRJ CONSTRUCTION · BESPOKE SIP GARDEN ROOMS
Garden rooms.
Made for your life.
A little distance from the house.
A whole new world of possibility.
Bespoke insulated garden rooms for work, wellbeing and everyday living across Hertfordshire, Buckinghamshire, Essex and North London. Built with Structural Insulated Panels and shaped around you.
From £1,400 per sqm including VAT · Individual specification and quotation
MORE THAN AN EXTRA ROOM
Your garden.
A fresh perspective.
A quiet office. A personal gym. A place to create, unwind or welcome someone in.
Every TRJ garden room starts with the way you want to use it. We bring together the layout, natural light, materials and practical details to create a space that feels connected to your home while offering a welcome change of scene.
Our SIP garden buildings are designed for daily use throughout the year. Insulation, heating and ventilation work together as part of the specification, with finishes selected to suit your property and priorities.
WHAT WOULD YOU MAKE ROOM FOR?
One garden.
Many possibilities.
Start with the purpose.
We shape the room around it.
WELLBEING, CLOSER TO HOME
Garden gyms ↗
Design a private training space around your equipment, floor requirements and ventilation, with room to stretch and move comfortably.
15sqm from £21,000+ Guide price including VAT
ROOM FOR YOUR IDEAS
Creative studios ↗
Make space for music, art or a favourite hobby. Storage, lighting and any acoustic requirements become part of the design brief.
15–20sqm from £21,000–£28,000+ Guide price including VAT
EVERYDAY FREEDOM
Multi-use garden rooms ↗
Bring together relaxation, hobbies and family activities in a flexible room. Glazing and the layout help the space connect naturally to the garden.
20sqm from £28,000+ Guide price including VAT
COMFORT, CONSIDERED
Rooms with bathrooms ↗
Discuss a WC or shower room alongside the main space. Water, drainage, ventilation and the intended use need to be considered from the outset.
20sqm+ from £30,000+ Guide price including VAT
A PROFESSIONAL SETTING
Business & therapy rooms ↗
Create a calm place for appointments, treatments or meetings. Discuss access, privacy, facilities and the planning requirements for your proposed use.
15sqm from £21,000+ Guide price including VAT
ENGINEERED FOR EVERYDAY LIFE
Comfort starts
with the structure.
Explore the detail behind
your bespoke SIP garden room.
Insulation built in
A rigid insulating core sits between structural OSB faces. Careful detailing of joints and openings supports thermal comfort.
Explore the detail ↗Airtightness, with ventilation
A carefully sealed envelope helps reduce unwanted draughts. Appropriate ventilation remains part of the design.
Explore the detail ↗A substantial specification
125mm SIP walls and 150mm roof and floor systems form the basis of our garden-room construction.
Explore the detail ↗A coordinated project
Discuss groundwork, structure, electrical provision and the finishes together. Your quotation confirms the agreed scope.
Explore the detail ↗THE FINISHING TOUCHES MATTER
Built around
the whole brief.
Explore the specification.
Your quotation confirms the inclusions.
Foundations
Engineered screw piles are our usual starting point, with the final system selected for the ground conditions and design.
SIP structure
Structural OSB faces bonded to an insulating core create the panel system for the walls, roof and floor.
Interior & decoration
Plasterboard-lined walls, carefully finished joints and decoration provide a bright interior ready for your chosen furnishings.
Lighting & electrical provision
Plan internal and external lights, sockets and the supply connection around how you will use the building.
Windows & doors
Grey uPVC French doors are a standard option. Aluminium glazing is available for slimmer sightlines and a different finish.
Floor finishes
Discuss laminate, engineered wood, vinyl or another suitable finish around comfort, wear and the intended use.
External cladding
Choose from timber, composite cladding or a rendered finish to complement the building and its surroundings.
Roof covering
EPDM roofing is an option for flat roof designs, with suitable alternatives considered for pitched roofs.
Extras & upgrades
Air conditioning, skylights, sound systems, CCTV, network cabling and upgraded glazing can be discussed as part of your specification.
REAL ROOMS. REAL POSSIBILITIES.
See what
a garden can become.
Discover existing TRJ projects.
Open a photograph or explore the details.
FROM THE TRJ PORTFOLIO
Garden Gym in Bishop’s Stortford ↗
A private home gym planned around daily training.
FROM THE TRJ PORTFOLIO
Garden Gym with Sauna & Shower Room ↗
A garden gym with sauna and shower facilities.
FROM THE TRJ PORTFOLIO
Craned Garden Room in Central London ↗
A garden room installation using crane access.
FROM THE TRJ PORTFOLIO
Garden Recreation Room in Watford ↗
A separate room for leisure and recreation.
FROM THE TRJ PORTFOLIO
London Garden Rooms and Garden Offices ↗
Explore further London garden-room examples.
FROM THE TRJ PORTFOLIO
Large SIP Garden Room with Storage in Chiswell Green ↗
A garden room incorporating practical storage.
FROM THE TRJ PORTFOLIO
Bespoke SIP Garden Room with Hidden Storage in Borehamwood ↗
A bespoke room with discreet storage.
A STARTING POINT FOR YOUR PLANS
Your room.
Your specification.
Bespoke SIP garden rooms
from £1,400 per sqm including VAT.
Garden room guide price
From £14,000+Garden room guide price
From £21,000+Garden room guide price
From £28,000+Garden room guide price
From £35,000+Guide prices include VAT. Your layout, site access, foundations, glazing, services and finishes determine the final price. Bathrooms and premium upgrades affect the specification and cost.
FROM THE FIRST IDEA TO YOUR FIRST DAY
A clear path
to your new space.
Every project starts
with a conversation.
Your idea
Share your postcode, approximate size, intended use and photographs of the garden and access.
Your design
Discuss the layout, materials, planning route, services and agreed specification.
Your build
Coordinate foundations, SIP construction, openings and electrical provision around the project plan.
Your finishing touches
Complete the finishes and details that make the room ready for its intended use.
BESPOKE GARDEN ROOMS, BUILT LOCALLY
North London.
The Home Counties.
We work across Hertfordshire, Buckinghamshire, Essex and North London. Find local information for Watford, Essex and Hertfordshire, then send your postcode so we can discuss your project.
YOUR QUESTIONS, CONSIDERED
A little clarity.
A confident start.
Cost, construction and the practical details of your garden room.
How much does a garden room cost?
Our bespoke SIP garden rooms start from £1,400 per square metre including VAT. Guide prices are £14,000+ for 10sqm, £21,000+ for 15sqm, £28,000+ for 20sqm and £35,000+ for 25sqm. The final quotation depends on the design, foundations, access, glazing, finishes and extras.
Are your garden rooms suitable for year-round use?
Yes. SIP insulation and carefully detailed construction support comfortable everyday use. Heating, cooling and ventilation are planned around the building, its location and your requirements.
What can I use a garden room for?
Home offices, gyms, creative studios, hobby rooms, relaxation spaces and therapy or business rooms are all options. Tell us how you intend to use the building so the layout and specification can reflect it.
Can you build a garden room with a bathroom?
Yes. WC and shower facilities can be included where the site and services allow. Drainage, water supply, ventilation and the intended use affect the design and cost; these are assessed for your project.
Why choose SIP construction?
Structural Insulated Panels combine an insulating core with structural OSB faces. Our garden-room specification uses 125mm SIP walls and 150mm roof and floor systems, with the full construction details agreed for each design.
Do garden rooms need planning permission?
The planning route depends on the property, dimensions, position and intended use. We discuss the requirements for your proposal; sleeping accommodation or business use may require a different approach from a domestic garden office.
What foundations do you use?
We typically use engineered screw pile foundations. The suitable foundation system is assessed against ground conditions, loads, access and the proposed design.
What is included in a garden room build?
A typical specification covers the foundations, SIP structure, roof, external finish, doors and windows, plasterboard-lined interior and electrical provision. Flooring, decoration and upgrades are discussed with you, and your quotation sets out the exact inclusions.
How long does construction take?
Timing depends on size, specification, site access, ground conditions and any approvals. We discuss a project programme before work starts, rather than give one fixed build time for every garden room.
Which areas do you cover?
We build garden rooms across Hertfordshire, Buckinghamshire, Essex and North London, including Watford and Barnet. Send your postcode so we can confirm arrangements for your location.
MAKE ROOM FOR SOMETHING NEW
What could your
garden become?
Tell us your location, approximate size and how you want to use the room. We will discuss a bespoke layout, specification and quotation.
