Warmer drier healthier #7: Assessing retrofitted external wall insulation techniques

Abbreviation
BRANZ Research Now - Warmer drier healthier #7
Valid from
1/09/2023

Information provider
BRANZ Limited
Information type
Research report
Format
PDF

Description

Retrofitting insulation into external timber-framed walls with no underlay brings the risk of water transfer from the back of the cladding to the insulation and/or framing.

BRANZ investigated this in direct-fixed weatherboard walls. Using drainage plane mesh together with underlay was found to be the best method of reducing moisture transfer. It also allows for thicker insulation than some other options.

Scope

This Research Now includes:

  • Test procedure and analysis
  • Results 
    • Insulation without underlay or separation (no mitigation)
    • Insulation without separation and with retrofitted underlay (a method in NZS 4246:2016)
    • Insulation with 20 mm separation and without underlay (a method in NZS 4246:2016)
    • Insulation with separation via drainage plane mesh and underlay (an alternative method)
    • Insulation with separation via drainage plane mesh and underlay taping underlay to framing or tucking strip of underlay behind framing
    • Inspecting the framing before retrofitting
  • Conclusion
For assistance with locating previous versions, please contact the information provider.
View on Information Provider website Download this resource (PDF, 327KB)
For assistance with locating previous versions, please contact the information provider.
This resource is not cited by any other resources.

Warmer drier healthier #7: Assessing retrofitted external wall insulation techniques

This document is not CITED BY any other resources:

Warmer drier healthier #7: Assessing retrofitted external wall insulation techniques

Description

Retrofitting insulation into external timber-framed walls with no underlay brings the risk of water transfer from the back of the cladding to the insulation and/or framing.

BRANZ investigated this in direct-fixed weatherboard walls. Using drainage plane mesh together with underlay was found to be the best method of reducing moisture transfer. It also allows for thicker insulation than some other options.

View on Information Provider website Download this resource (PDF, 327KB)
Warmer drier healthier #7: Assessing retrofitted external wall insulation techniques
Description

Retrofitting insulation into external timber-framed walls with no underlay brings the risk of water transfer from the back of the cladding to the insulation and/or framing.

BRANZ investigated this in direct-fixed weatherboard walls. Using drainage plane mesh together with underlay was found to be the best method of reducing moisture transfer. It also allows for thicker insulation than some other options.

View on Information Provider website Download this resource (PDF, 327KB)
This resource does not cite any other resources.

Warmer drier healthier #7: Assessing retrofitted external wall insulation techniques

This resource does not CITE any other resources.
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