Helpful? 0

Why no "ridge vents" for walls?

I've been thinking about wall insulation vs. attic insulation. Why is it that ventilation is not needed in wall assemblies using fiberglass or cellulose insulation in the same way that it is needed for roof assemblies. I certainly know this is true, but discover I'm not clear on the science behind it. For old 2x4 walls, I think it might be because the insulation is thin enough so the dew point isn't reached within the assembly. But what about double stud walls and other higher insulation assemblies?

Asked by Hallie Bowie
Posted Thu, 01/10/2013 - 16:37
Edited Thu, 01/10/2013 - 16:59

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Hallie,
The short answer to your question: if you are building a double-stud wall, you should definitely include ventilation. The ventilated air gap between the siding and the wall sheathing is usually called a rainscreen gap.

I have been recommending the practice for thick walls for some time; for example, see How Risky Is Cold OSB Wall Sheathing?

Answered by Martin Holladay, GBA Advisor
Posted Thu, 01/10/2013 - 16:58

Other Questions in Energy efficiency and durability

Flat roof insulation

In Energy efficiency and durability | Asked by Angela M | Nov 22, 13

Large structure with sealed attic / fiberglass

In Green products and materials | Asked by W Ahrens | Oct 22, 14

Spray foam over XPS on external wall

In Energy efficiency and durability | Asked by Jeff M | Oct 22, 14

How does the attic fan work? And can you use it in the winter?

In General questions | Asked by Aleasha Jeffries | Oct 22, 14

Double wythe CMU vs. Thermomass

In Green building techniques | Asked by leo kloop | Oct 22, 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!