Reclaimed High-Density Geofoam for Interior Basement Wall Insulation?
WhaleWatch67
| Posted in Energy Efficiency and Durability on
I have the opportunity to buy some reclaimed high-density GeoFoam ($400 for 24 2″ 4×8 sheets) for a basement interior insulation project. My plan would be to use a double layer to get me about R16 with some furring on top of it to provide a place for wiring and drywall.
Are there any issues with GeoFoam vs. any other EPS? I know it’s typically used for below-grade work under foundations, roadways, and the like.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
I don't see a problem using this material here, it looks like it will perform pretty much the same as "regular" EPS would in the same application. You'd just need to have the usual thermal barrier over it, which could be a sheet of 1/2" drywall.
Bill
Will do on the drywall. Thanks!
I don't know of any differences between Geofoam and other types of EPS insulation. Both come in a variety of compressive strengths, which also means a variety of R-values. Otherwise I don't see a reason why it wouldn't work. It's vapor permeable so I would include a vapor retarder on either the interior or exterior side of the EPS, leaving the wood furring on the interior side of the membrane. Some people argue that a vapor retarder is not necessary but I don't want an endless source of moisture (the soil) to pump moisture into the house.
Thanks! I've been going back and forth on this. The foundation is relatively new and *supposedly* well sealed on the exterior (no sign of moisture in the past six months at any rate) but I do worry about whether that will hold true in a couple years or ten years or 20.
It might have the same flame retarding chemicals in as EPS made for building insulation. I'm not convinced that's the best fire protection approach but it's the one in code. Options include,
1. Check with the manufacturer or vendor, or comparison test a sample, to find out if it has it.
2. Ignore code if you want to and feel like you can get away with it, but overkill the other fire protection, e.g. fire rated 5/8 drywall and be meticulous about fire taping it.
Definitely going to be covering it with drywall and paying attention to the fire details. One part of this will be a workshop where there will be some chance of the occasional spark. Thanks!