Cantilevered steel balconies and canopies are among the worst thermal bridges in a building. A continuous steel beam running from the heated interior to the cold exterior pulls heat straight through the insulation, chilling interior surfaces and creating condensation and mould risk on the beam inside the envelope.
A balcony or canopy thermal break cuts that path. The beam is split at the envelope line, end plates are shop welded to each side, and an STB-1 structural thermal break pad is bolted between them to carry the moment and shear while blocking heat flow.
How a Thermally Broken Canopy Connection Works
A typical bolted end plate thermal break connection includes:
- Interior and exterior end plates welded to the backspan and cantilever beams
- STB-1 pad between the plates, drilled to match the bolt pattern
- High-strength bolts sized for the longer grip through the pad
- Thermal break washers and bushings isolating the bolts on the exterior side
Compression from the moment is carried by bearing through the STB-1 pad, tension by the bolts, and shear through the bolts and the pad interface.
Design Considerations
- Compressive capacity: STB-1 is rated to 48,000 psi in compression, so bearing on the pad rarely governs.
- Rotation and stiffness: a thinner pad gives a stiffer connection and less tip deflection at the end of the cantilever.
- Bolt bending: thicker pads lengthen the grip and increase bolt bending under shear. Check bolts for combined shear, tension and bending.
- Long-term load: STB-1 is a creep-resistant thermoset composite that holds its shape under sustained dead load.
- Fire: STB-1 is rated ASTM E84 Class A and Euroclass B.
- Thermal target: pad thickness and bolt isolation together set the point transmittance of the connection.
The thermal break design guide covers each check in more detail.
Final connection design, including bolt sizing, pad thickness and load checks, is the responsibility of the project’s structural engineer of record. We supply material data and fabricate to the approved design.
Why Specify STB-1 for Balconies and Canopies
- Manufactured in Canada and shipped in 5–7 days
- Pads, washers and bushings fabricated as one kit, labelled by connection
- Compressive strength of 48,000 psi with thermal conductivity of 1.055 BTU·in/hr·ft²·°F
- Standard thicknesses from 1/4″ to 2″
Weighing a bolted pad against a proprietary module? Read Thermal Break Pads vs Structural Thermal Break Modules.
Request a Quote or Data Sheet
Send us your connection drawings, bolt schedule or load requirements and we will quote STB-1, TBF, washers and bushings cut and machined to your specification. Data sheets and design support are available for engineers and architects.
Call 800-580-4195 or use the form below. STB-1 typically ships in 5–7 days; TBF in as little as 3 days.