Furring strips on top of XPS?

randall.miller · 08-22-2011, 06:13 PM

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 · 08-23-2011, 11:21 AM

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 · 08-23-2011, 11:15 PM

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

AGWhitehouse · 08-24-2011, 07:14 AM

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

**Gary in WA** · 08-27-2011, 03:22 PM

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/docum...wall-approach/), seal the rim joists with foam board and canned foam.
http://www.buildingscience.com/docum...m-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 · 08-27-2011, 05:20 PM

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

**Gary in WA** · 08-27-2011, 08:39 PM

Thanks, they are always changing the site! Here is the first choice, the one I thought I had, LOL.
http://www.buildingscience.com/docum...-at-rim-joist/

Gary

08-22-2011, 06:13 PM	#1
randall.miller Newbie Join Date: Aug 2011 Posts: 2	Furring strips on top of XPS? 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

08-23-2011, 11:21 AM	#2
AGWhitehouse Architectural Designer Join Date: Jul 2011 Location: Connecticut Posts: 1,370	Furring strips on top of XPS? 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. __________________ Life's too short...so enjoy it! To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

08-23-2011, 11:15 PM	#3
randall.miller Newbie Join Date: Aug 2011 Posts: 2	Furring strips on top of XPS? Thanks for the reply. I'm having a bit of difficulty finding them. Do you have any idea how much they cost?

08-24-2011, 07:14 AM	#4
AGWhitehouse Architectural Designer Join Date: Jul 2011 Location: Connecticut Posts: 1,370	Furring strips on top of XPS? Don't know the $, but a "real" building supply will have them. The box stores won't... __________________ Life's too short...so enjoy it! To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

08-27-2011, 03:22 PM	#5
Gary in WA Moderator Join Date: Mar 2009 Posts: 8,843	Furring strips on top of XPS? 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/docum...wall-approach/), seal the rim joists with foam board and canned foam. http://www.buildingscience.com/docum...m-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 __________________ Clothes taking longer to dry? Clean the dryer screen in HOT water if using fabric softener sheets. They leave a residue that impedes air-flow, costing you money. Clean the ducting in the last six months? 17,000 dryer fires annually!

Furring strips on top of XPS?