Replies

1. 
   Malcolm_Taylor | Apr 29, 2022 07:12pm | #1

   Callum,

   Sleggs in Langford has a metal shop that will fabricate any profile you want out of perforated stock in any colour. They have the standard J flashing for the bottom of rain-screens in the warehouse, but for corrugated cladding it's best to use an L flashing with a hemmed drip-edge.

   If your WRB is behind the foam you should get it deep enough to cover the bottom of both the insulation and cladding. If the WRB is in front of the rockwool you can cover the bottom of the foam with a wood block and attach the flashing to it.

   If you are getting a permit for this work, run it by your inspector. Our CRD one here in Juan de Fuca wants a vertical layer of furring under the horizontal one. My own reading of the code is that corrugated metal cladding on its own meets the requirements without any furring at all - but that's a battle I seem to have lost.

2. 
   callumshill | Apr 30, 2022 11:58am | #2

   Hi Malcolm, ok that's great to know. It makes at least one part of this work easier. I'll double check with my inspector to make sure he's ok with this detail.

3. Expert Member
   BILL WICHERS | Apr 30, 2022 05:16pm | #3

   If you don't go with Malcolm's option of a perforated channel (which is probably the best way to go), you should go with either stainless steel screening (if it's subject to aggressive little beasties), or fiberglass (if it's pretty safe from little beasties that can chew and burrow). The reason for this is that aluminum screen will tend to corrode fairly quickly in many enviornments, so it gets ineffective in a few years time. Fiberglass will last forever IF it doesn't get physically damaged, and some times of critters (notably mice, but also some more aggressve insects) can chew through it pretty easily. Stainless steel screen is pretty impervious to just about anything, but it's also the most expensive option by far. If you do decide to use stainless streel screen, I recommend either 304 or 316 alloy, with 316 being preferred, but also more expensive.

   BTW, if you go with perforated aluminum J channel, see if you can get it in 5052 alloy, which has about the best corrosion resistance of the common aluminum alloys.

   Bill

1. 
   Malcolm_Taylor | Apr 30, 2022 06:02pm | #4

   Bill,

   In most situations I agree, but with corrugated metal cladding you can't cover the bottom with screen the way you can with a flat profile siding.

4. 
   seabornman | May 04, 2022 03:48pm | #5

   I assume you'll have a drip trim at the bottom which covers the corrugations. I used fiberglass screen with a backup of GAF ridge vent material: the stuff that looks like heavy steel wool. I placed the screen under the strapping, friction fit the vent stuff in, and wrapped the screen over the strapping. I did vertical strapping, so you'll have to figure out how you're going to maintain open air with vertical.