FREESTANDING STEEL SUB FRAMES
Designed, Supplied & Installed with Comprehensive Structural Reports
At 360 GSS, we specialise in freestanding steel sub frame systems designed to support balconies, roof terraces, decking and balustrades without relying on the primary building structure for support.
Our freestanding systems are engineered to be self-supporting, transferring loads vertically and distributing them safely across the roof or terrace surface. This approach avoids imposing loads on the façade or internal structure, delivering a robust and compliant solution suitable for both new-build and retrofit projects.
WHY CHOOSE 360 GSS FOR FREESTANDING STEEL SUB FRAMES?
PROJECT-SPECIFIC ENGINEERING
No two roofs are the same. Every freestanding steel sub frame is designed around the specific constraints of the building, including roof build-up, load capacity, usable footprint and intended use.
We consider factors such as balcony projection, barrier height, wind exposure and live loading to produce a frame that performs structurally while remaining visually proportionate to the property.
INDEPENDENT STRUCTURAL PERFORMANCE
Freestanding steel sub frames are engineered to function without structural reliance on the building itself. Loads are not transferred back into walls or floor edges, reducing stress on the existing structure and avoiding the need for intrusive fixings.
This makes freestanding systems an effective solution for retrofit installations, heritage buildings and developments where fixing into the primary structure is restricted or undesirable.
CONTROLLED LOAD TRANSFER & STABILITY
Load management is central to the design of every freestanding sub frame we produce. Forces generated by occupancy, wind and balustrade loading are spread across the supporting surface using engineered base plates, spreader elements and ballast where required.
This controlled load transfer ensures long-term stability while protecting the roof or terrace construction below from point loading or overstress.
COMPATIBILITY WITH BALUSTRADES & DECKING
Our freestanding steel sub frames provide a rigid, level base for the installation of glass balustrades and decking systems. Balustrade channels and posts are fixed directly to the steel structure, ensuring barrier loads are managed correctly at source.
This approach allows for clean detailing, consistent alignment and uninterrupted views while meeting all required safety and loading standards.
READY TO DISCUSS YOUR FREESTANDING STEEL SUB FRAME?
360 GSS provides a complete service, from initial design development and structural calculations through to fabrication and on-site installation.
Every freestanding steel sub frame is delivered with full engineering support, ensuring building control compliance and dependable long-term performance.
QUALITY ASSURED & FULLY GUARANTEED
All freestanding steel sub frames are manufactured using high-grade steel and finished with corrosion-resistant coatings suited to exposed roof environments.
Our work is supported by professional indemnity insurance, ensuring your installation meets the required standards for durability, safety and structural integrity.
FREQUENTLY ASKED QUESTIONS
What is a freestanding steel sub frame?
A freestanding steel sub frame is an independent structural system designed to support balconies, roof terraces, decking and balustrades without transferring loads into the main building structure.
When is a freestanding system the preferred option?
Freestanding frames are commonly used where the existing structure cannot support additional loads, where façade fixings are restricted, or where a roof-level installation needs to remain structurally independent.
How are loads supported without fixing into the building?
Loads are transferred vertically and distributed across the supporting surface using engineered base plates, spreader systems and ballast where required, avoiding reliance on walls or slabs.
Can freestanding sub frames support glass balustrades and decking?
Yes. Freestanding frames are designed to support glass balustrades, composite or timber decking and associated imposed loads while maintaining stability and regulatory compliance.
Are freestanding steel sub frames suitable for retrofit projects?
Yes. Freestanding systems are particularly well suited to retrofit installations, allowing balconies or roof terraces to be added without altering or strengthening the existing building structure.
Do freestanding sub frames require structural calculations?
Yes. All freestanding steel sub frames should be supported by project-specific structural calculations to confirm load capacity, stability and compliance with building control requirements.
Can freestanding sub frames be used on flat roofs and podium decks?
Where used on flat roofs, freestanding sub frames are typically designed as non-penetrative systems to protect the waterproofing layer and avoid thermal bridging.
How long do freestanding steel sub frames last?
When manufactured from high-quality steel and finished with appropriate corrosion protection, freestanding steel sub frames are designed for long-term external use and durability in exposed environments.