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Text Lesson 3 of 3

Reflective and Bulk Insulation

Use insulation product data correctly.

25 minRoof Assembly Compliance
Diagram for Reflective and Bulk Insulation
Roof Assembly Compliance Reflective and Bulk Insulation
How to use the diagram Read the visual first, then connect each label to the lesson text and your calculator inputs. The aim is to make every assumption visible before you calculate.

Learning Objective

Understand what evidence is needed for roof insulation claims.

Reflective insulation

Reflective systems depend on surface reflectivity and adjacent air spaces. Without the required air space, the expected performance may not be achieved.

Bulk insulation

Bulk insulation depends on installed thickness and condition. Compression can reduce performance.

Practice Task

  • Review one roof insulation product sheet.
  • List installation requirements.

Calculator Tip

Do not use declared product values without checking installation assumptions.

Worked Example: Roof Assembly Evidence

Scenario

A pitched roof uses ceiling-level bulk insulation and a reflective membrane under the roof covering.

Calculator Entry

Create separate entries if different roof zones use different assemblies or insulation locations.

Step-by-step method
  1. 1List each roof layer from outside to inside.
  2. 2Check whether required air gaps exist for reflective layers.
  3. 3Confirm bulk insulation thickness and continuity.
  4. 4Flag penetrations, compressed areas and thermal bridges for inspection.
Expected conclusion

A declared product value is useful only when the installed assembly matches the product assumptions.

Common Mistakes

  • Using insulation product values without checking air gaps and installation conditions.
  • Ignoring gaps, compression, service penetrations or thermal bridges.
  • Combining unlike roof assemblies into one unexplained value.

Quick Knowledge Check

1. What should you confirm before applying this lesson to a project?

Air spaces are shown.

2. Which piece of evidence should support the main input in this lesson?

Review one roof insulation product sheet.

3. What is the safest action if the information is incomplete?

Flag the missing evidence, use a conservative assumption where appropriate, and avoid claiming compliance until the information is confirmed.

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