Foam packing peanuts as crawlspace backfill
Jon_Harrod
| Posted in Energy Efficiency and Durability on
My coworker and I were batting around the idea of using EPS packing peanuts to backfill drainage trenches during crawlspace encapsulation. The idea would be to level the surface and support the vapor barrier using a free-draining material much lighter and less expensive than gravel. There is an online crawlspace product store (Crawlspace Depot) that sells EPS peanuts for this purpose (local pickup in NC only); they appear to be essentially the same as what we could buy at a local office supply store. I’d be interested in knowing if anyone has experience with this approach.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
I would be concerned with the compression strength of the peanuts. The compressive forces underground in a drainage trench are quite high, especially with dirt on top of it and equipment driving over top of it. I would question the properties of the peanuts after they are compressed together. I don't know but would think they would not drain as well. This would be exactly what you don't want in a drainage trench. I can also imaging trying to back fill with peanuts and the wind picks up. I'm sure the neighbors would love it.
Jon,
Your idea would probably work. If you use 4 inches of peanuts to level the entire crawl space floor, however, it's going to be funny to walk on (crawl on).
If used for a drainage trench, either material (crushed stone or packing peanuts) can get clogged by fines (silt) if there is enough flow. But you probably know that.