Radiant barrier wall assembly
user-6184358
| Posted in General Questions on
Hi,
I have 1980’s addition the west wall is 2×4 construction with most likely R13. The wall bakes in the afternoon sun. Would it help to make a air gap type rain screen that has a radiant barrier in it?
US Climate zone 4, or zone 16 in California. Hot dry summer with cold winters with the possibility of snow. On the eastside of the Sierra Nevada Mountain Range, with a view of Nevada.
Part 2 would be is there a wildland fire compliant rain screen detail to follow?
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Replies
A lot of polyiso insulation has a foil coating, the manufacturer claims a boost of R0.5 in the insulating value because of it. But generally in walls you're not going to see a lot of radiation, which is transmission of heat from hot to cold across a line of sight. Most walls don't have gaps in them, the heat transmission is from conduction, which is direct contact, and sometimes via convection if there are large enough gaps for air to circulate.
Thanks- seem like not worth the effort for R5
If your diagnosis of the problem is correct “that most of the heat coming thru this wall is radiant energy from the sun.”
Then the solution would be to cover the wall with sheets of silver galvanized sheet spaced about 3 inches away from the wall with vents to allow air flow between the panels and the wall.
R13 should block 92.3% of the energy.
Walta