Non-Penetrative Steel Sub Frames
BESPOKE DESIGN, FABRICATION & STRUCTURAL REPORTS
Structural support without compromising waterproofing.
Non-penetrative steel sub frames provide structural support for balconies, roof terraces and elevated structures while helping protect waterproofing membranes and insulated building surfaces.
360 GSS designs, fabricates and installs bespoke steel sub frames engineered to minimise unnecessary penetrations, reduce thermal bridging and accommodate project-specific structural loads.
From residential roof terraces to complex commercial installations, our systems combine precision structural steel fabrication, engineering expertise and professional installation to deliver reliable, long-lasting support.
Roof Protection
Designed to minimise penetrations through waterproof membranes and insulated roof or terrace structures.
Thermal Efficiency
Specialist frame designs help reduce thermal bridging associated with conventional structural connections.
Structural Strength
Bespoke steel frames engineered around project loads, fixing requirements and site conditions.
Non-Penetrative Steel Frame Options & Specifications
360 GSS designs and fabricates bespoke non-penetrative steel sub frames for projects where waterproofing protection and structural stability are essential.
Our capabilities include:
For projects requiring independent structural support, explore our freestanding steel sub frames.
Our capabilities include:
- Bespoke steel sub frames manufactured to project specifications.
- Balcony and terrace supports for residential and commercial properties.
- Waterproofing protection through reduced membrane penetrations.
- Thermal bridging reduction within insulated roof and terrace structures.
- Structural calculations and reports to support engineering and approval.
- Made-to-measure fabrication based on drawings, loads and site conditions.
- Protective finishes including galvanising and powder coating.
- Supply and installation coordinated around project requirements.
For projects requiring independent structural support, explore our freestanding steel sub frames.
Our Non-Penetrative Steel Frame Installation Process
STEP 1
Request a Quote
Share your drawings, measurements or project requirements so we can assess the proposed structure and waterproofing considerations.
STEP 2
site survey & measure
Where required, we assess the existing structure, waterproofing, insulation, dimensions and installation conditions.
STEP 3
DEPOSIT, Design & Engineering
Following approval, a 50% deposit secures the project while structural calculations, drawings and specifications are finalised.
STEP 4
Manufacturing of the System
Your bespoke steel sub frame is fabricated to the agreed engineering specifications, with suitable finishes applied.
STEP 5
Install & completion
Our specialists install and align the framework, taking care to protect the surrounding structure and waterproofing system.
Protecting Waterproofing & Structural Performance
Roof terraces and elevated balconies often require structural support without unnecessarily disturbing existing waterproofing or insulation.
Our non-penetrative steel sub frames are designed to:
For complete balcony installations, explore our non-penetrative balcony and balustrade systems.
See how we used a bespoke, low-profile steel subframe to protect roof waterproofing while supporting a frameless glass balustrade in our Twyford glass terrace balcony project.
Our non-penetrative steel sub frames are designed to:
- Minimise penetrations through waterproof membranes.
- Reduce potential water ingress risks associated with fixings.
- Limit thermal bridging through insulated structures.
- Support balconies, roof terraces and elevated platforms.
- Accommodate glass balustrades, decking and architectural features.
- Meet project-specific structural loading requirements.
- Provide durable support for residential and commercial applications.
For complete balcony installations, explore our non-penetrative balcony and balustrade systems.
See how we used a bespoke, low-profile steel subframe to protect roof waterproofing while supporting a frameless glass balustrade in our Twyford glass terrace balcony project.
Why Choose 360 GSS for Non-Penetrative Steel Frames?
Bespoke Design
Steel frames tailored to individual roof structures, loading requirements and site conditions.
Structural Expertise
Engineering calculations and technical reports available to support project requirements.
Precision Fabrication
Made-to-measure steelwork manufactured for accuracy, durability and reliable fitment.
Roof Protection
Solutions designed to minimise unnecessary waterproofing penetrations.
Specialist Installation
Experienced installers coordinating structural connections, alignment and finishing.
Complete Support
Design, fabrication and installation managed as one coordinated service.
FREQUENTLY ASKED QUESTIONS
Have questions about non-penetrative steel sub frames?
Our team can advise on structural requirements, waterproofing considerations and bespoke fabrication for your project.
Our team can advise on structural requirements, waterproofing considerations and bespoke fabrication for your project.
Ready to get in touch?
If your project requires a structural support solution that protects waterproofing systems while reducing thermal bridging, a non-penetrative steel sub frame could be the ideal solution.
360 GSS provides design, fabrication and installation services across London, Buckinghamshire, Berkshire, Oxfordshire, Hertfordshire, Surrey and throughout the UK for suitable projects.
360 GSS provides design, fabrication and installation services across London, Buckinghamshire, Berkshire, Oxfordshire, Hertfordshire, Surrey and throughout the UK for suitable projects.
What is a non-penetrative steel sub frame?
A non-penetrative steel sub frame is a structural support system designed to reduce or eliminate the need for fixings through waterproof membranes and insulated roof or terrace build-ups.
Can a steel frame be installed without penetrating a roof?
In suitable circumstances, yes. Non-penetrative steel frames can be designed to avoid conventional fixings through the primary waterproofing membrane. Suitability depends on the existing structure, available support and required loads.
What are non-penetrative steel frames used for?
They are commonly used for roof terraces, balconies, elevated platforms and architectural installations where protecting waterproofing is an important consideration.
Do non-penetrative steel frames prevent thermal bridging?
They can help reduce thermal bridging by limiting direct structural connections through insulated building elements. The actual thermal performance depends on the frame design and wider construction details.
Do you provide structural calculations and reports?
Yes. Project-specific calculations and technical reports can be provided to support structural design and Building Control approval where applicable. Learn more about our structural engineering services.
What is the difference between freestanding and non-penetrative steel frames?
Freestanding frames provide independent structural support, while non-penetrative systems are designed to avoid or minimise penetrations through waterproofed surfaces. Some projects may incorporate both approaches. Explore our freestanding steel sub frames for more information.
Do you fabricate and install the steel frames?
Yes. 360 GSS provides bespoke fabrication, supply and installation, with each frame manufactured around the agreed structural drawings and project requirements.
How much does a non-penetrative steel sub frame cost?
Costs depend on the dimensions, structural loads, engineering requirements, protective finishes and installation complexity. Contact our team with your project details for a tailored quotation.