Roofing & enclosure
Thermal Bridging in Steel Buildings Explained
Learn how steel framing and cladding attachments affect heat flow, why assembly performance matters, and what to request when comparing insulation systems.
What a thermal bridge means
A thermal bridge is a part of the enclosure through which heat moves more readily than through the surrounding area. Steel framing and connections can create these paths where they pass through or interrupt insulation. MBMA defines this behavior in its energy guide, and MCA highlights cladding attachment methods as an important part of effective thermal performance.
The practical implication is that an insulation product label and a finished wall are different things. An estimate can correctly name a material R-value yet leave the assembled wall's behavior unresolved. Ask which performance value belongs to the material and which belongs to the complete roof or wall.
References: Energy Guide for Metal Building Systems: Code Compliance (PDF) · Thermal breaks in cladding support assemblies
Locate the repeated and occasional bridges
Start with a wall section and mark the steel that crosses the insulation line. Then look for conditions that do not appear in the typical section, such as edges of openings, canopies, and changes in wall thickness. The purpose is to identify questions for the enclosure designer, not to remove structural connections.
A repeated girt or clip arrangement may need one documented assembly evaluation, while an unusual canopy attachment may need a separate detail. Keep these two kinds of issue on separate lists so a good typical-wall solution is not mistaken for a review of every condition on the building.
Ask for comparable thermal information
When comparing proposals, request the assumptions behind the claimed assembly performance. A number without its associated section, attachment arrangement, and evaluation basis is hard to use responsibly.
| Information | Why it matters | Useful record |
|---|---|---|
| Insulation location | Shows where steel may interrupt the layer | Marked roof or wall section |
| Attachment system | Connects structural and thermal decisions | Clip or girt schedule |
| Assembly performance | Supports a comparison beyond material labels | Applicable calculation or test basis |
| Transitions | Identifies conditions outside the typical assembly | Base, eave, corner, and opening details |
Understand what a thermal break can and cannot do
A thermal break introduces a less conductive part into a heat-flow path. Its usefulness depends on where it is located and how the full connection is configured. A pad under one component is not evidence that every route through the connection has been addressed.
Treat proposed thermal-break components as part of the specified attachment assembly. Their dimensions, material properties, and effect on the connection need appropriate review. Do not substitute a generic insulating piece, alter fastener engagement, or interrupt a required load path in an attempt to improve an energy number.
References: Energy Guide for Metal Building Systems: Code Compliance (PDF)
Compare two wall proposals fairly
Suppose two wall proposals list the same insulation thickness. One places the insulation between steel members; the other uses a different arrangement around the cladding supports. The similar thickness labels do not settle whether their installed thermal performance is equivalent.
Ask each proposer to mark the insulation and support paths on the same style of wall section and provide the applicable assembly performance. Then ask the design team to review energy, condensation, structural attachment, and constructability together. Keep all four decisions in the comparison instead of choosing the proposal with the largest isolated R-value.
Carry the accepted assembly into construction
Once the assembly is selected, record which components and dimensions are essential to its evaluated configuration. Connect those requirements to purchasing and submittal review so a later clip or insulation substitution triggers a coordinated check.
A useful field review checklist identifies continuity at the wall base, roof edge, openings, and penetrations, as well as the repeated support arrangement. Ask the project team which conditions require documentation before covering. Retaining that information helps future alterations preserve the original enclosure intent rather than unintentionally recreate conductive paths.
Common questions
Does thicker insulation automatically solve thermal bridging?
No. Insulation thickness and conductive attachment paths are separate parts of the assembly review. Compare the evaluated configuration as a whole.
Can a thermal break replace a structural connection?
No. Any thermal-break component used in a connection must be coordinated with the required structural attachment and approved assembly details.
Sources & further reading
Use the current documentation for the exact product and project. Source links do not imply a partnership or endorsement.
- Energy Guide for Metal Building Systems: Code Compliance (PDF) Metal Building Manufacturers Association
- Thermal breaks in cladding support assemblies Metal Construction Association
Prepared with AI assistance. Linked references require current project-specific review. How these guides are prepared.
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