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BOREHAMWOOD, HERTFORDSHIRE · PROJECT CASE STUDY
A bright main room. A separate store. One continuous cedar frontage.
Costi and the TRJ team built this bespoke SIP garden room with a finished main space and a discreet storage compartment, bringing two practical uses together under one roof.
01 / THE BRIEF
The project combined a fully finished garden room with a separate, practical store. The storage needed its own external access while the front of the building kept a clean timber finish.
The detailed project specification set out an 8 m × 3.3 m SIP structure, a partitioned storage compartment approximately 1.5 m wide, and a concealed entrance within the Red Cedar frontage.
The side and rear elevations used cement particle boards with an anthracite grey rendered finish, specified with the nearby boundaries in mind.
02 / ORIGINAL FLOOR PLAN
The original project drawing shows how the 8 m × 3.3 m building was divided: a larger main room on the left and a separate storage compartment on the right. Both spaces open directly onto the front step.
The drawing marks the main space at 6,055 mm across, with a 3,200 mm glazed opening formed by the French doors and two fixed panels. Inside, the room was finished with skimmed plasterboard, white paint, laminate flooring and MDF skirting.
The 1,500 mm storage compartment sits behind the right-hand cedar frontage. Its separate 900 mm entrance keeps access independent of the main room. An OSB finish, dedicated light and socket make it a practical storage space.
The drawing also shows a 400 mm front step. The overall building footprint is 26.4 m²; the room dimensions shown above are the labels on the original drawing.
03 / BUILD DETAILS
Red Cedar cladding with concealed fixings gives the front its consistent finish. The storage door blends into that cladding, with a composite decking step running along the front.
A 400 mm front canopy shelters the entrance. The roof has an EPDM membrane, with a black gutter running along the rear.
Structural insulated panels form the base, walls and roof. Cement particle boards and anthracite grey RAL 7016 render finish the side and rear elevations.
The specification records anthracite grey uPVC French doors, 1,600 mm wide × 2,030 mm high, with two fixed glazed panels each measuring 800 mm × 2,030 mm.
Eight internal LED downlights, four external LED lights and five white double sockets, including one in the store. A consumer unit and a surface-mounted LED storage light complete the recorded electrical specification.
An LG air conditioning unit with smart internet control provides heating and cooling for the main room. The storage compartment retains its practical OSB finish.
These details describe this project’s specification. The design and specification of a new garden room are agreed around its own site and intended use.
04 / THE BUILD & FINISHED RESULT
The project photographs record the construction and fit-out, showing the structure before the cedar frontage and finished interior were completed.
01 / THE STRUCTURE
The construction photographs show the SIP floor being assembled, followed by the wall and roof panels. The internal partition creates the separate store at the right-hand end.
02 / THE ENVELOPE
The French doors and fixed glazing were fitted into the front opening. Red Cedar completed the front, with the store entrance concealed in the same cladding; the side and rear elevations used boards and render.
03 / THE FINISHED ROOM
The completed main room has white walls, laminate flooring, recessed lighting and wall-mounted climate control. Separate access to the store keeps the finished room clear of the items stored next door.
05 / CUSTOMER FEEDBACK · TRUSTPILOT
The customer highlighted the progress photographs, open communication and attention to detail throughout the project.
Read the original Trustpilot review ↗“Costi and the team have recently completed my garden room. Costi was brilliant at keeping us informed throughout the project sending us progress pictures throughout and the lines of communication were always open. I was so impressed by there attention to detail and the care they put into the project which I have to say is rare to find these days. Worth every penny and very happy with the finish. Highly recommend these guys!!”
Customer review · Garden room · published on Trustpilot
06 / PROJECT PHOTOGRAPHS
Explore the completed frontage, the main room, the storage and the construction stages. Select a photograph to open its full-size view.
Project photographs: TRJ Construction. The gallery includes the completed building and work in progress.
07 / PROJECT QUESTIONS
The detailed project specification records external dimensions of 8 m × 3.3 m, giving a footprint of 26.4 m². This includes the main room and separate storage compartment.
The store has its own front entrance, clad in Red Cedar to blend into the frontage. The compartment is approximately 1.5 m wide and has an OSB finish.
Yes. The specification includes an LG air conditioning unit with smart internet control for heating and cooling.
YOUR NEXT PROJECT
Planning a bespoke garden room or garden office with integrated storage in Borehamwood or elsewhere in Hertfordshire? Tell Costi how you want to use the space and share photographs of the proposed site.
Explore our build process and planning guidance as you develop the brief.
TRJ Construction Ltd is a specialist Structural Insulated Panel (SIP) construction company delivering high-performance garden rooms and granny annexes across North London, Hertfordshire, Buckinghamshire and surrounding counties.
We design and build engineered living spaces using 150mm roof and base SIP systems, 125mm structural walls and professional K-Render finishes — creating buildings designed for durability, efficiency and long-term value.
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