STB-1 is a high-strength structural thermal break plate for steel-to-steel and steel-to-concrete connections that pass through the building envelope. Installed between end plates, base plates and embeds, STB-1 carries compression and shear loads while interrupting the conductive heat path that turns canopies, balconies, shelf angles and rooftop posts into thermal bridges.
STB-1 is a thermoset, reinforced composite manufactured in Canada. We cut, drill and machine every pad to your connection drawings, make matching thermal break washers and bushings in house, and typically ship in 5–7 days.
STB-1 Mechanical and Thermal Properties
| Property | Units | Test Method | STB-1 |
|---|---|---|---|
| Compressive Strength | psi (MPa) | ASTM D695 | 48,000 (330.9) |
| Flexural Strength | psi (MPa) | ASTM D790 | 25,000 (172.4) |
| Tensile Strength | psi (MPa) | ASTM D638 | 11,000 (75.8) |
| Shear Strength | psi (MPa) | ASTM D732 | 16,326 (112.56) |
| Compressive Modulus, 1/2″ (12.7 mm) | psi (MPa) | ASTM D695 | 291,194 (2,007.7) |
| Compressive Modulus, 1″ (25.4 mm) | psi (MPa) | ASTM D695 | 400,671 (2,762.5) |
| Thermal Conductivity | BTU·in/hr·ft²·°F | ASTM C177 | 1.055 |
| Surface Burning Characteristics | Class | ASTM E84 | Class A |
| Reaction to Fire | Euroclass | EN 13501-1 | B |
| Operating Temperature | °F (°C) | — | -20 to +250 (-29 to +121) |
| Standard Thicknesses | in (mm) | — | 1/4, 1/2, 3/4, 1, 2 (6.4, 12.7, 19.1, 25.4, 50.8) |
STB-1 conducts heat more than 1,300 times less than aluminum, more than 350 times less than steel and more than 100 times less than stainless steel. Data are nominal values. Download the STB-1 technical data sheet (PDF) for your project file.
Fire Performance
STB-1 is fire rated to ASTM E84 Class A and Euroclass B (EN 13501-1). The material is designed to char when exposed to flame, reducing the oxygen available to a fire, which makes it suitable for structural connections where combustible thermal break materials would not be accepted.
Where STB-1 Is Used
- Steel balconies and canopies – bolted end plate moment and shear connections at cantilevered beams
- Masonry shelf angles and relieving angles – shims and pads at slab-edge connections
- Column bases, roof posts and rooftop dunnage – base plates for screens, HVAC, solar and signage supports
- Parapets, roof-to-wall intersections and roof penetrations
- Curtain wall and cladding support connections
- Steel column bases on foundation walls
For low-load, non-moment connections where maximum R-value matters more than strength, see TBF High Density Thermal Break.
Cut and Machined to Your Drawings
We are the manufacturer, not a distributor, so STB-1 pads come to you finished and ready to install:
- Cut to exact plate dimensions from 1/4″ to 2″ thick
- Bolt holes and slots drilled to your hole pattern
- Matching isolation washers and bushings machined to your bolt size
- Parts labelled by connection mark for easy installation
- Expedited service available on cut parts
Send your shop drawings or a bolt schedule and we will quote the complete thermal break package.
Choosing STB-1 Thickness
Thicker pads reduce heat flow but lengthen the bolt grip, which increases bolt bending under shear and moment. Most steel connections use 1/2″ to 1″ STB-1; thicker pads are used where thermal targets demand it and the connection is designed for the longer grip. Our thermal break design guide walks through the trade-offs, and the guide specification gives you ready-to-edit spec language.
Comparing products? See STB-1 vs Armatherm FRR.
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.