Uploaded November 2023 | Updated September 2026, 1 hour ago
Metal roof decks can only be insulated with rigid insulation installed above the decking, as the thermal conductivity of the metal deck and the high potential for air leakage can cause condensation to form. By installing all of the insulation on the outside of the assembly, combined with proper air sealing techniques, the underside of the metal deck is kept close to the interior temperatures and relative humidity, eliminating the potential for condensation (for the majority of building uses), as the lack of temperature fluctuations provides the highest level of moisture safety in addition to a high level of energy efficiency. Blown-in and batt insulation should be completely avoided in metal roof deck applications, as these insulation types are often installed within the interstitial cavity between the rafters or joists. This is not only energy inefficient but poses a high moisture risk even with an airtight vapor barrier membrane at the ceiling level, as the chances of that remembering being installed perfectly it's extremely low, and the conductivity of the metal decking is less forgiving than wood substrate. This means that hybrid roofs with a combination of rigid insulation and cavity insulation should also be avoided.
Read the full article on insulating metal roof decks here: asiri-designs.com/resources-1/f/insulating-metal-roof-decks
This video clip is from Flat Roof Parapet Details Explained (For Architects + Contractors): youtu.be/-6y2ooXxqfU?si=haJZkCavRieHxbxE
More flat roof articles and resources: asiri-designs.com/resources-1?blogcategory=Flat+Roofs
Get my climate specific Flat Roof Design Guides available here: asiri-designs.com/shop
Request building science consulting services for your project: asiri-designs.com/consulting
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**Featured Music From Pixelbay**
Space Chillout by PenguinMusic: pixabay.com/music/upbeat-space-chillout-14194
Metal roof decks can only be insulated with rigid insulation installed above the decking, as the thermal conductivity of the metal deck and the high potential for air leakage can cause condensation to form. By installing all of the insulation on the outside of the assembly, combined with proper air sealing techniques, the underside of the metal deck is kept close to the interior temperatures and relative humidity, eliminating the potential for condensation (for the majority of building uses), as the lack of temperature fluctuations provides the highest level of moisture safety in addition to a high level of energy efficiency. Blown-in and batt insulation should be completely avoided in metal roof deck applications, as these insulation types are often installed within the interstitial cavity between the rafters or joists. This is not only energy inefficient but poses a high moisture risk even with an airtight vapor barrier membrane at the ceiling level, as the chances of that remembering being installed perfectly it's extremely low, and the conductivity of the metal decking is less forgiving than wood substrate. This means that hybrid roofs with a combination of rigid insulation and cavity insulation should also be avoided.
Read the full article on insulating metal roof decks here: asiri-designs.com/resources-1/f/insulating-metal-roof-decks
This video clip is from Flat Roof Parapet Details Explained (For Architects + Contractors): youtu.be/-6y2ooXxqfU?si=haJZkCavRieHxbxE
More flat roof articles and resources: asiri-designs.com/resources-1?blogcategory=Flat+Roofs
Get my climate specific Flat Roof Design Guides available here: asiri-designs.com/shop
Request building science consulting services for your project: asiri-designs.com/consulting
------------------------------------------------------------------------------------------------------------------------
**Featured Music From Pixelbay**
Space Chillout by PenguinMusic: pixabay.com/music/upbeat-space-chillout-14194
