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Guardian Structural Technologies

Continuous insulation: what it means and what it fixes

Continuous insulation is insulation uninterrupted by framing across the whole envelope. Codes increasingly require it because cavity insulation alone cannot deliver the performance the model assumed.

The definition codes use

Continuous insulation is insulation that runs without thermal bridges other than fasteners and service openings, across all structural members. The phrase appears in the energy codes precisely because insulation between framing members is not continuous, and the difference between the two is large enough to matter for compliance.

In practice, continuous insulation is usually a layer of rigid board on the outside of the sheathing. That works, but it adds a trade, a fastening problem and a thickness the cladding has to accommodate.

Thermal bridging in a framed wall against a cored panel In a framed wall every stud runs from the warm side to the cold side, conducting heat past the insulation. In a panel the insulating core is continuous and no member spans the assembly. Framed wall Every stud is a path from warm to cold Insulation is interrupted every 16 to 24 in Shield™ panel The core runs unbroken through the panel No member spans warm face to cold face
Wood conducts heat roughly four times better than the insulation beside it, and steel hundreds of times better. That is why a wall's whole-wall R-value is lower than the number on the insulation, and why the geometry of the assembly matters more than the rating of any one material in it.

Why passive house makes it the first principle

The five passive house principles begin with a building envelope that employs continuous insulation throughout, without thermal bridging. It is first because every other measure depends on it: an airtight envelope on a bridged wall still loses heat, and high-performance glazing cannot compensate for a wall that leaks heat through its studs.

A panel whose insulating core is continuous by construction satisfies the principle without a separate layer, which is why panelised systems appear in passive projects.

What Guardian publishes

  • Guardian states the Shield™ system is the first, and currently the only, panel system in the US certified by the Passive House Institute US.

    Source · Products page; PHIUS certificate

  • Passive building principle one, as Guardian publishes it: employs continuous insulation throughout its entire envelope without any thermal bridging.

    Source · Products page, passive housing principles

Written by Data Subsystems, for Guardian Structural Technologies. Last updated .

Drafted from Guardian Structural product literature and published building-science sources. Awaiting Guardian technical review. Confirm any figure against the current product documents or ask us before you rely on it in a design.

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