Bumped Out Rain Screen – Slicker vs Furring
With 2” rigid foam attached around my slab foundation, I want my siding to protrude beyond it by a little bit. BTW I’m not doing exterior rigid insulation (doing this: https://www.greenbuildingadvisor.com/article/furred-continuous-insulation-wall-assembly-to-meet-2021-codes
My thought on exterior assembly to get to minimum of 2.25”:
– 1/2” CDX sheathing
– Blueskin VP100 SA WRB
– BO Slicker rain screen (1/4”)
– horizontal furring strips (3/4”)
– vertical shiplap siding (3/4”)
Questions :
– should I skip the slicker and just do vertical furring under the horizontal furring for cost savings as well as to also make it thicker? Any downside?
– I do like the idea of more air space of the Slicker though, so if I stick with Slicker, has anyone ever cut into strips? As in, could I save money by cutting horizontal strips (say 5” wide) to be placed behind the 1×4 horizontal furring with the intent of saving money, and also use less material by about half. Or does it have to be full wall coverage? Obviously the channels would be oriented correctly.
Thank you in advance for your thoughts!
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Replies
NewSkills,
Two thoughts:
- The other way to make up some of the thickness of the foam on the foundation is to set your sill- plates out so they cantilever past the outside of the foundation.
- It's a bit of a wash between two layers of furring, and using one with Slicker. The two layers gives you more air movement for drying, but is more vulnerable to fire spread in the deeper cavity. If you go with Slicker I see no downside to using strips.
Thanks for the reply Malcolm. I had thought about hanging the sill by 1/4" or so as well. And I appreciate your input on the rain screen. I've got some time before I need to really make a decision, so I'll continue to ponder the tradeoffs. All the best!
NewSkills -
You might price out Slicker vs furring strips. We've found Slicker to be surprisingly expensive in our market (PNW). Also, I'm not sure what Obdyke says but my gut says strips of Slicker might compress more than you want, thereby subjecting your whole assembly to potential string-lining and straightening. Hopefully not the case with solid furring if your walls are straight. Also you're not leaving yourself much breathing room on total buildup depth if the Slicker compresses!
Bottom line, my gut says things will go smoother with solid furring.