Norbord Solarbord sheathing reflects up to 97% of sun’s radiant heat?
Hi all — Norbord makes a foil-faced OSB roof sheathing board called Solarbord. They state that it reflects up to 97% of the sun’s radiant heat, and that it can reduce attic temps as much as 30 degrees (I assume Fahrenheit).
Link: https://www.norbord.com/na/roof-sheathing/solarbord/
What do you think of the claims? They cite an ASU study, but they don’t link to it or name it as far as I can see (I mean authors, title, journal, etc — the normal citation). They claim that the ASU study found that Solarbord reduced HVAC run time by 20%. (I assume the ASU they refer to is my alma mater, Arizona State University, which would make sense for research on radiant barriers in hot climates.)
I’m thoroughly confused on the issue of radiant barriers at this point. Don’t radiant barriers need an air gap to function properly? These are OSB roof sheathing/decking boards — they’d be used in place of conventional OSB or plywood boards. That means they wouldn’t normally have an air gap, and I don’t see an air gap in Norbord’s illustrations.
Norbord is a large company with over $2.4 billion in revenue in 2018 (https://finance.yahoo.com/quote/OSB/financials?p=OSB — yes, their stock symbol is OSB). Solarbords are sold at Lowe’s (I don’t know about HD). I would expect Norbord to be mindful of the accuracy of the claims they make, and to be smart about not getting into legal trouble. But the claims are remarkable — I’ve not seen anyone else claim that foil sheathed OSB roof boards can reflect 97% of the sun’s radiant energy and so forth…
Thanks for your input.
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Replies
Blue, I can see you're getting into it with this radiant barrier stuff.
I would suggest reading this if you already haven't:
https://www.greenbuildingadvisor.com/article/oooh-shiny-stuff-radiant-barrier-fundamentals
Read the comments too.
As far as the product you linked: it didn't take me more than 1 or 2 clicks to see that they say the sheathing must be installed face down into the attic with an air-space. It violates no physics. Its just another low-e surface facing an air-gap in your roof layers.
As far as their numbers claims, it will all depend on so many factors, most especially the insulation levels.
I would take note of Dana's comment in your other thread in regards to cool roofs and that they have testing standards and can be had at nearly zero up-charge.