Furring Strip Directions
sethcooper94
| Posted in General Questions on
For vertical siding like a metal panel, the furring strips for the rain screen have to be horizontal, which hurts the drying potential and movement of air.
Why not put them diagonal?
What say you? Rockwool is the continuous insulation if you’re curious. Climate zone 5A.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
I put the furring strips horizontally and loose zero sleep over it.
Most metal panels have enough striations and bumps to allow for some air flow anyways.
Akos, i don't see how the water could drain properly if the first layer of furring is horizontal over the wrb. Water would pool on furring strips and possibly damage the wall, would it not?
This is contrary to everything i read here on this site.
I'm also planning to install vertical metal siding but over double vertical then horizontal furring.
Thanks
thierry19,
In our wet PNW climate we don't have a choice. Our code here in BC requires a clear vertical gap next to the sheathing.
But even in wet climates do you ever get enough moisture penetrating the cladding, or condensing, that it would need to drain? I suspect that much more common is that areas of the back of the cladding (and perhaps smaller areas of the WRB behind) might get saturated, and that persistent damp could cause rot. But the chief benefit of the rain-screen gap is not the drainage plane, it's the capillary break, and the drying the cavity affords.
So in many climates horizontal furring might work fine, as long as the profile of the cladding allows good air movement.
All that musing aside, most metal wall cladding needs very infrequent support. It's not a lot of work to run vertical furring @ 24"oc, then horizontal @32".
In our wall design here the insulation is directly against the WRB. The horizontal strapping would be on the face of the Rockwool.
There would be 3/8'' air gaps every other striation on the metal as others have mentioned
Rockwool is self draining so it won't hold water. The horizontal strapping is definitely not an issues.
Sample of one, but I had horizontal strapping over house wrap exposed to the elements for longer than I should have, one wall had no overhang and was getting full runoff from as section of the roof. Pulled back the strapping in a couple of spots before the cladding went up and there was no signs of any water damage.