# Furring strips on top of XPS?



## randall.miller (Aug 22, 2011)

I'm considering a couple ways of insulating & finishing our basement walls:
-1- Glue 4x8 sheets of 1-1/2" XPS foam board to the concrete block walls. Seal seams with tape. Attach furring strips to XPS with tapcon screws through the furring strip and XPS into the concrete block wall. Attach drywall to the furring strips, which would leave a 3/4" or so space between the XPS and the drywall. Any thoughts?
-2- Attach z-channel metal furring strips to the concrete block wall, 24"o.c. The z-channel furring strips' design holds XPS foam board in place with little or no wall area uninsulated. They also have a surface to attach the dry wall to. Have any of you used these? What kind of price? Do they work as advertised? 

Thanks,
Randall


----------



## AGWhitehouse (Jul 1, 2011)

Both methods work, though the z-channel has more thermal break point than the the furring strips, but it is negligable. Z-channels are the easier install of the two scenarios. With Z's you're shooting direct to concrete instead of 2-3/4" of material before you even hit concrete.


----------



## randall.miller (Aug 22, 2011)

Thanks for the reply. I'm having a bit of difficulty finding them. Do you have any idea how much they cost?


----------



## AGWhitehouse (Jul 1, 2011)

Don't know the $, but a "real" building supply will have them. The box stores won't...


----------



## Gary in WA (Mar 11, 2009)

The furring strips (3/4") would be better if you added insulation at the air-space. Air seal the drywall (ADA- http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/), seal the rim joists with foam board and canned foam. 
http://www.buildingscience.com/docu...arriers/critical-seal-spray-foam-at-rim-joist

The moisture condensing on the metal at the concrete wall would/could be a problem leading to rusting out due the foam storing moisture for extended periods and also contribute slightly to thermal heat sinks all over the wall.

Gary


----------



## AGWhitehouse (Jul 1, 2011)

GBR, the second link doesn't work...


----------



## Gary in WA (Mar 11, 2009)

Thanks, they are always changing the site! Here is the first choice, the one I thought I had, LOL. 
http://www.buildingscience.com/documents/information-sheets/critical-seal-spray-foam-at-rim-joist/

Gary


----------

