Wonderful information on your website.
We are in a 5A climate zone, our basement that is mostly below grade does not have any type of air or moisture barrier above grade, but has a visible stone veneer that prevents correcting this problem. The below grade portion does have a asphalt base waterproofing coating that seems to be effective.
We are looking to install insulation on the interior to correct condensation issues that are given our humid climate. Can you just install the insulation without the stud and gypsum walls? A contractor who is giving us a quote to install insulation and gypsum also suggested installing z channels directly to the CMU( instead of wood studs) , but I am concerned about those transferring heat and rusting over time. Thoughts?
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You can get Z channel made from plastic instead of steel.
There is and issue with most foam board insulation which you need to be aware of. It burns and gives off toxic gasses. This means that it must be covered up with drywall or other suitable material.
There are brands and types of foam board insulation constructed to allow installation without the drywall covering. One is Dow Thermax.
https://insulation4us.com/products/dow-thermax-sheathing-4-x-8-polyiso-all-sizes is one vendor ( I have no financial interest)
You will note that this quite a bit more expensive than other foam board choices, but it may make sense depending on your needs.
Thank you for your quick response. So, for clarification, wouldn't the foil be problematic on the thermal sheathing? It would seem to act like a vapor barrier. Our 5A climate is one of those you are damned if you do, and damned if you don't when discussing vapor barriers in winter & summer.
If it is not an issue, that would be great because my husband hates sheetrock. (Looking at a creative way to cover the walls). Might even consider using metal ribbed roofing panels on top of the 2" insulation board if the vapor movement is not something to be concerned about. Again thank you for your assistance.
If you do use an alternative wall consider hanging drywall and fire taping it then hanging something over it so it is a fire rated assembly, especially if you don’t spring for the fire rated foam insulation
Yes it would act like a vapor barrier.
The issue is moisture that collects when moist air contacts a surface which has a temperature below the dew point, and is in a location where this moisture can not escape, and can do damage.
I would not use the thermax with Z channel, but bond it right to the wall and seal all joints. (this would mean no hanging stuff from the walls) ( I have this in a storage room and utility room in my basement.)
If you want a finished space, the Z channel would be a way to go to support the drywall.
There are also other choices. Dow makes a whole system for basements. mix of insulation, materials that are mold resistant, and different finishes.