Project Challenges: Building a Retractable Sunroom on an Existing Rooftop
Site Constraints
Three site conditions shaped the design.
1. Open, unshaded roof deck: The roof is a large, level paved terrace with no permanent overhead structure — full solar exposure and no existing load-bearing frame at roof level.
2. Existing perimeter condition: The roof edge is defined by a rendered parapet wall carrying a conventional glass balustrade. The render shows the weathering and hairline cracking typical of an exposed rooftop in a humid, monsoon climate. The new structure therefore had to be set back from, and structurally independent of, that balustrade.
3. Existing glazed volume and adjacent construction: A glazed stair/lift enclosure occupies part of the deck, and an active tower crane with high-rise construction stands immediately adjacent. This constrained delivery routes and lifting windows, and forced the new roof geometry to negotiate the existing glazed box without transferring load into it.
Design Response to the Existing Rooftop
Because the existing parapet could not be relied upon for restraint or waterproofing, the sunroom was developed as a self-supporting frame seated on the roof slab through a purpose-built base and track assembly, draining away from the parapet rather than over it. The elevation drawings record the original 600 mm-high low wall and a 120 mm galvanized steel base as the working datum.
What the Client Needed
1. Premium all-weather venue: A high-end rooftop restaurant with unobstructed views and all-weather usability.
2. Large openable area: Sufficient opening capacity for natural ventilation and flexible scene switching.
3. Climate durability: Typhoon-season wind resistance, waterproofing and durability in high-temperature, high-humidity conditions.
4. Aesthetic integration: A finish and profile that match the luxury positioning of the riverside commercial complex.
5. Intelligent control: Stable, silent, intelligent control of the retractable system.
Retractable Sunroom Design for the Rooftop Restaurant
The scheme resolves the brief into a single glazed envelope that reads as one continuous architectural element, with the retractable section occupying the dining deck and the fixed glazing terminating the run at the service end. Three decisions carry the design.
Multi-Arch Retractable Geometry
The retractable roof uses a repeated shallow-arch profile rather than a flat panel. The arch gives the canopy visual lightness against the existing rendered building block, and it lets the panels nest into a compact stack without a tall parking structure above the roof line.
Glazing Strategy for Panoramic Views
The perimeter is kept in glass down to the existing parapet level so the panoramic river view is not interrupted at seated eye height — the enclosing structure does the weather work without becoming a visual barrier.
Flexible Dining Layout
Banquette seating is laid out in rows parallel to the roof run, leaving a clear central circulation spine. This layout works in both configurations: enclosed for climate-controlled dining, open for terrace service.
Technical Specifications
| Project Item | Specification |
|---|---|
| Project location | Ho Chi Minh City, Vietnam |
| Application | Rooftop restaurant |
| Total project area | Approximately 629 m² (client-stated) |
| System | Fixed curtain wall + electric retractable sunroom |
| Retractable configuration | 3-track / 6-panel multi-arch system |
| Aluminium main beam | 6063-T5, 100 × 180 × 5.0 mm |
| Glazing | 5 + 0.76 + 5 mm laminated tempered glass |
| Drive | 200 W high-precision silent servo motor |
| Opening area | Up to 75% |
| Water management | Track water troughs + EPDM sealing strips |
Technical specifications supplied with the project
Shop Drawings and Dimensional Control
The shop drawings set out a modular roof run on a repeating pitch, with a dedicated parking zone for the stacked panels at one end and an end zone that transitions into the fixed glazing. A separate elevation drawing, labelled "Sunroom B", documents one complete unit.
Key Dimensions from the Shop Drawings
All values in millimetres unless noted.
Overall envelope — repeated on drawings 01, 02 and 04
Plan drawings — roof plan (drawing-01) and opening direction plan (drawing-02)
Section (drawing-03)
Elevation, "Sunroom B" (drawing-04)
Notes carried on the drawings: "Sunroom track sink" · "The original building has a 600 mm high low wall" · "120 mm galvanized steel" · "Glass guardrail".
SUNRAY Retractable Sunroom Engineering Solution
Fixed Curtain Wall
High-strength aluminium framing with large-format laminated tempered glass.
Provides permanent weather enclosure together with thermal and acoustic separation.
Designed to integrate visually with the existing building façade and the premium character of the venue.
Electric Retractable Sunroom
3-track, 6-panel electric retractable sunroom with a multi-arch design.
6063-T5 heavy-duty aluminium main beam, 100 × 180 × 5.0 mm, for high load capacity.
5 + 0.76 + 5 mm laminated tempered glass.
Structural Reinforcement and Water Management
Added steel support structure, triangular braces and thickened base plates.
Purpose-made track water troughs combined with EPDM sealing strips for water management and sealing.
Electric Drive and Control System
200 W high-precision silent servo motor.
One-button opening and closing, with manual operation in the event of a power failure.
Optional lighting and sunshade systems to upgrade the dining experience.
How SUNRAY Manufactured the Retractable Sunroom
1. Profile machining: Retractable-sunroom profiles are batch-machined on a four-head CNC end-milling centre, which keeps the notching and end-milling of mating profiles consistent across a full production run — the tolerance chain that governs whether the panels track parallel on site.
2. Profile protection: Finished powder-coated extrusions are foam-wrapped and stacked with protection film in the factory store, preventing surface damage and abrasion before packing.
3. Structural steel connections: The connection plates for the added steel support structure are CNC/laser-cut and drilled as a matched set, with lightening holes that reduce plate weight while preserving the bolted grid. Drilling off the machine rather than on site is what allows the modular bolted connections to be assembled without field welding.
4. Hardware set: Machined brackets, seals and gaskets, the drive unit and a complete fastener kit are prepared as a matched assembly set.
Project Results: A Flexible All-Weather Rooftop Dining Concept
The fixed + retractable system provides up to 75% opening area, improving natural ventilation and operational flexibility.
The dual configuration is designed to switch between an open terrace and an enclosed restaurant according to operating and weather conditions.
The glazed design supports the luxury positioning of the riverside venue while preserving panoramic views.
Where This Fixed + Retractable Solution Can Be Used
This fixed + retractable concept is suitable for premium hospitality applications such as rooftop restaurants, sky bars, clubs, luxury lounges and cafés. The same design logic can also be adapted to resort lounges and high-end villas where clients want weather protection without permanently giving up an open view.