Can someone please tell me if this “radiant barrier” is doing more damage than good? I feel like it may be since it is essentially just foil tacked onto the sheathing. Will this cause the roof surface to overheat and lead to curling of the shingles? Any help is much appreciated!
Maybe this link will help.
Start at the RIMA site for answers. https://rimainternational.org/technical/
I will say in the Pacific NW that a thermal barrier could trap moisture against the sheeting and create conducive conditions for mold/fugal growth. Also, it can hold heat between the rafter bays and not give the roof adequate ventilation or access to roof vents for cooling causing the roofing material (assuming it asphalt material) to over heat; causing effects such as curling and/or premature granular loss.
If you look up in the IRC its not approved for that application you’ve shown and would recommend removal of rolled thermal barrier material to allow ventilation as designed.
I was afraid of this as well. Thanks for your response.
Radiant barriers do not work (or not work) just because they are there. They must be installed correctly and for a specific purpose.
How, where, and why it is installed determines if it works as intended. It may be used to keep radiant heat in or out. They do not absorb radiant heat (it reflects). They are highly conductive. There should be an air space between the barrier and the radiating heat source. Ventilation of this air gap should not be restricted by any means. If properly ventilated it will not raise the temperature of the roofing materials.
Barriers installed in contact with the roof deck will conduct the absorbed radiant heat of the roof. This negates the reason for it’s installation. It also cools the roof decking and subsequently raises the attic air temperature (ventilation requirements again…).
Discussion about moisture; that would be a “depends” (again ventilation issues at fault).
The silver OSB roof decking you see is to keep heat in the attic, not keep it out. Shingles absorb solar radiation. Because they have no air space with the roof deck the foil on the OSB will conduct heat into the OSB. Though it will not radiate very much, it will radiate more because of it’s increased temperature. The heat transfer is conductive/convection rather than radiated, which will increase attic temps if inadequate ventilation exists.
Recommend you bone up on all of the aspects of radiant barriers before making any recommendations in your reports.