Tech Talk:  Premier SIPS Deliver Built-in  Continuous Insulation (Ci) Required by Energy Codes

The International Codes (I-Codes)—published by the International Code Council (ICC), including the IRC, IBC, and IECC—serve as model codes for many state and local municipalities when developing building regulations. For example, Washington State’s 2021 Energy Code, took effect in March 2024, closely follows the energy requirements outlined in the IRC, IBC, and IECC.

A key requirement in these codes is the need for continuous insulation (Ci) in wood-framed walls to minimize thermal bridging at studs, blocking, and headers, thereby improving energy efficiency. While this requirement significantly enhances a building’s thermal performance, it also presents challenges for designers and builders.

The Challenges of Continuous Insulation (Ci) in Traditional 2x6 Wood-Framed Construction

While effective in improving energy efficiency, the Ci requirement for wood-framed walls creates several design and construction challenges:

• Increased material and labor costs – Ci materials and their installation adds to overall project expenses.
• Thicker walls – Window and door jambs must be extended to accommodate the additional layer of exterior insulation.
• Fastener and attachment complexity – In some climate zones, Ci must be several inches thick, requiring longer, more expensive specialty fasteners.
• Weatherproofing concerns – Ci applied to the exterior must be properly integrated with weather-resistant barriers (WRBs) and flashings in the building assembly.
• Water management challenges – In areas requiring a rain screen or drain plane (e.g., Marine Climate Zone 4), additional design considerations are needed to prevent moisture buildup.
• Difficult cladding installation – Applying exterior finishes becomes more complex, increasing installation time and costs.

The cumulative effect of these challenges results in higher construction costs and greater design complexity for builders and building owners.

SIPs: A Smarter Alternative to Ci for Wood-Framed Walls

While adding Ci to traditional site framed wood construction is an effective way to meet energy codes, there’s a better, more advanced building system that naturally meets and exceeds energy code requirements: Premier Structural Insulated Panels (SIPs).

SIPs provide a high-performance building envelope that simplifies energy code compliance with one product, while eliminating the need for cumbersome Ci installation. With Premier SIPS, designers and builders achieve energy-efficient construction without the added materials, labor, or complications associated with Ci.

How Premier SIPS Meet Energy Code Requirements

National and local energy codes allow for two approaches to meeting insulation requirements:

• Prescriptive Method – Requires Ci in wood-framed construction to achieve a minimum R-value per climate zone.
• Performance-Based U-Factor Alternative – Evaluates the total thermal performance of a wall or roof assembly by calculating its U-Factor.

Premier SIPS excel under the Performance-Based U-Factor Alternative, offering a structural, insulated building envelope that eliminates thermal bridging caused by excessive dimensional lumber that exists in traditionally site framed wood structures.

Why SIPs Are the Ideal High-Performance Building Envelope

SIPs are factory-engineered structural laminated panels consisting of a solid rigid insulation core structurally laminated between two structural OSB facings. The strength of each SIP eliminates the need for interior wall studs, reducing the amount of thermal bridging in walls and roofs to less than 5% of the total envelope area—compared to 25% or more in traditional wood framing. A SIP can be manufactured in sizes up to 8'x24' in a single panel, further eliminating any lumber components causing thermal bridging. 

This continuous insulation results in 90-95% uninterrupted thermal performance, making SIPs the perfect solution for achieving superior energy efficiency under the Performance-Based U-Factor Alternative in national, state, and local energy codes.

SIPs vs. Ci: A Proven Performance-Based Approach

Find energy performance calculations for SIP wall and roof assemblies that illustrate their superior insulating performance on our SIP Design Best Practices Resource Guide.  For example a SIP with a standard EPS insulation core delivers the following U-Factors (Upgraded GPS insulation cores deliver even higher thermal values):

• 6.5” SIP wall assembly – U-Factor: 0.043 (see Design BP Guide pg. 23)
• 10.25” SIP roof assembly – U-Factor: 0.026 (see Design BP Guide pg. 25)

These U-Factor calculations prove that SIPs naturally achieve high energy efficiency standards—without requiring additional Ci.

The Simple, Cost-Effective Solution for Energy Code Compliance

SIPs streamline construction by eliminating the time, labor, and cost associated with installing Ci in wood-framed buildings. By choosing Premier SIPS, builders and designers benefit from:

• A seamless, high-performance building envelope that exceeds modern energy codes.
• Elimination of Ci-related design and installation challenges.
• Reduced labor costs and faster installation, with large prefabricated panels reducing onsite work.
• Enhanced durability, thermal efficiency, and structural performance.

With Premier SIPS, architects, engineers, and builders can create simpler, stronger, and more energy-efficient structures—without the added complexity of Ci.

Get Started with Premier SIPS

Want to see how SIPs can eliminate the cost and complexity of Ci in your projects? Contact your local Premier SIPS Representative for expert guidance and technical support.