Thermal Bridging Analysis / Derating

Design With Confidence in a More Demanding Code Environment

Massachusetts energy-code compliance is increasingly focused on actual building-envelope performance—not just nominal insulationvalues. Under the current, Stretch Code, and Specialized Code framework, project teams must account for real-world heat loss through cladding attachments, slab edges, parapets, window transitions, shelf angles, spandrelareas, and other thermal bridges.

Our thermal bridging analysis and derating calculation services help architects, owners, developers, engineers, and contractors translate complex code requirements into clear, defensible documentation for design decisions, C402.1.4 or C402.1.5 prescriptive requirements, energy modeling, permitting, and third-party review.

Thermal bridging analysis gives your team the data and documentation to make smarter decisions earlier. Whether you are planning a newconstruction project, evaluating a retrofit, or preparing for permit submission, we can help you quantify envelope performance and document compliance with confidence.

Our Services

We provide project-specific analysis that quantifies the effect of linear and point thermal bridges on opaque envelope assemblies. Our work supports Massachusetts energy-code compliance for both the prescriptive requirements, and the envelope assumptions for energy modeling pathways

·   Thermal bridging reviews for walls, floors, transitions, penetrations, and interface conditions.

·   Clear field assembly derating calculations for structural penetrations, continuous insulation fasteners, brick tie and other cladding fasteners.

·   Linear thermal bridge calculations for balconies, intermediate floors, interior vertical wall to exterior wall intersections, fenestration perimeters, parapets, brick shelf angles, wall to grade intersections, vertical wall corners.

·   Derated, effective opaque U-factor documentation total impact of point and linear bridges to support energy models, code narratives, and permit submissions.

·   Derated vertical envelope performance documentation total impact of point bridges, linear bridges and windows U-values onC402.1.4 or C402.1.5

·   Reviewer-ready reporting with visual takeoffs, assumptions, input values, calculation summaries, detail references, and recommended next steps.

·   THERM Modeling When the prescriptive bridge values are too conservative and none of the reference values are applicable to an assembly, THERM modeling can be used to get accurate, project assembly specific results. It can further be used to study impact of design alternatives on thermal bridging and subsequent envelope derating.

Why Thermal Bridging Matters

Nominal insulation values rarely tell the full story. Thermal bridges can significantly reduce effective envelope performance, increase heating and cooling demand, and create compliance gaps between design intent and actual performance. The U-values of derated opaque assemblies often end up being 2-3 times higher than the nominal assembly U-values. This means, a nominal assembly U-value of 0.03 could end up having a derated U-value of0.06-0.09 after thermal bridging is factored in. Accounting for this reality early gives project teams more time to address potential issues before details are locked in and procurement decisions are made.

With the Massachusetts code framework emphasizing envelope performance, derating calculations are no longer a niche technical exercise. They are a practical risk-management tool for projects that need to demonstrate compliance, manage cost, and maintain design flexibility.

Our Process

1. Review the project context. We identify the applicable code pathway, envelope assemblies, drawings, details, and modeling assumptions.

2. Map the thermal bridge conditions. We classify clear-field, linear, and point conditions that affect effective envelope performance.

3. Perform derating calculations. We quantify the impact of thermal bridges using prescriptive, reference and THERM modeling methods to establish adjusted assembly values for use in code documentation and energy modeling. We quantify the impact of thermal bridges using MA Code allowed Reference details whenever possible. For any project assemblies with no applicable Reference detail, we use the MA Code prescriptive method, unless the conservative nature of the prescriptive values are too detrimental to the design. If this is the case, we create custom THERM models and calculations for these project assemblies.

4. Coordinate with the project team. We help align architectural details, envelope products, engineering assumptions, and compliance strategy.

5. Deliver clear documentation. We provide concise, reviewer-ready reporting that supports submissions, internal decisions, and next-step design refinements.

Who We Help

·   Architects seeking defensible envelope performance assumptions and coordinated detailing guidance.

·   Developers and owners looking to reduce compliance risk, avoid redesign, and protect project schedules.

·   Energy modelers and MEP engineers who need reliable assembly inputs for performance-path documentation.

·   Contractors and construction managers evaluating envelope systems, cladding attachments, and constructability options.

·   Municipal, institutional, multifamily, commercial, and retrofit project teams navigating Massachusetts Base, Stretch, or Specialized Code requirements.

What You Gain

·   Design clarity: Understand how thermal bridges affect your projects code compliance.

·   Reduced budget risk: Compare façade strategies, envelope assemblies, products, and details before they become costly to change.

·   Reduced compliance risk: Provide organized calculations and assumptions that authorities having jurisdiction can follow.

·   Energy-model alignment: Give modeling teams accurate inputs earlier for performance-based compliance.

·   Long-term performance: Support buildings that perform closer to their intended energy and comfort targets

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