Skirting vents oriented vertically?

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Posts: 180
Joined: Thu Jan 06, 2011 12:39 am

Sat Jun 29, 2019 8:30 pm

I'm working up plans to replace my existing skirting, with metal roofing material. The vents that I'm am considering (best candidates) are rectangular, 16" x 8", and if oriented horizontally (long axis- 16") they would hit on the major ribs of the roofing material (I think 9" ribs). I would like to know if anyone has oriented vents horizontally on ribbed, metal roofing material, or could refer me to any reference of such. Skirting is only about 29" high, which might make this orientation more obvious?

If I go the normal orientation (long axis along the horizontal) I have to figure out how to frame and seal up the protrusions (specific concern/difficulty being the major ribs). Pretty much have to install from the back side, which would demand that protrusion cuts be clean (cannot cover with vent frame, as it would rest over top the major ribs [minor ribs present very little concern]). Looking at needing about 19 of these. If it were only a few I could stomach a more complex/detailed install.

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Location: Weedsport, NY

Sun Jun 30, 2019 7:45 am

Air is air, Horizontal or vertical. Do whatever is easiest for you.

"If I can't fix it, I can screw it up so bad no one else can either."

Posts: 242
Joined: Tue Feb 26, 2008 8:33 am
Location: Anna, Tx

Sun Jun 30, 2019 12:45 pm

After a few setbacks....
I'll start installing my new skirting this coming week. I've got some siding panels that have rot at the bottom, so that will be repaired first - and then it is on to the skirting!

I have read recently that venting is not necessary as long as there is thorough and complete ground cover. That said, I have no desire to crawl under this thing every few months to see if any mold is sprouting up on the floor joists. Which takes me back to just doing the venting and be done with it.

I will be using the Mueller RPN 26 gauge galvanized plus panels. I ordered the panels cut to lengths that are in 6 inch intervals. (i.e. 36" - 42" - 48" - 54" etc) And, as you hve encountered - the standard horizontal vent is more hassle than it is worth due to the ribs across the panels.

What i have found is round vents - in various sizes - with insect screens that require nothing more than a round hole for mounting. They kinda sorta look cheesy (I'm an over-builder - gotta be steel!) but it appears they would get the job done. I'm seeing everything from 2" to 8" - and pricing is all over the place.

Two of the 6" round grills provides about 56 sq in of area. Two of the 4" grills would provide about 25 sq in of area. Either one will fit easily between the ribs. A 4" bi-metal hole saw is pretty easy to find.

I don't know if it matters or not - but I like that using these round grills would actually spread out the air flow more evenly around the whole house.
Opportunity has a shelf life.

Posts: 180
Joined: Thu Jan 06, 2011 12:39 am

Sun Jun 30, 2019 7:05 pm

Greg, I was kind of hoping that someone else has found a need to do this. It's not a matter of how it would function (other than the installation issues, which is why I'm even considering this orientation), but how it would LOOK. I have yet to see ANY vent oriented like this. And, I can't believe that I would be the only one to face this dilemma.

Mark440, so, you're also running into the same issue as I? To answer the question about whether venting is required or not, YES: and the ratio is approximately 1 sq-ft of open air space to each 150 sq-ft of floor area. I will be replacing OSB siding that was used for skirting (not sure how old it is), which has suffered from water and rot. I'm about a month out from starting my project: also encompasses a total re-plumb, rim joist repair, crawlspace cleanout and belly wrap repair (which is why I'm going to take advantage of this by also doing the re-plumb [w/Pex]). Maybe I will learn from what you find out?

Posts: 180
Joined: Thu Jan 06, 2011 12:39 am

Sun Jun 30, 2019 8:13 pm

Mark440, I just took a look at those Mueller RPN panels. Those major ribs are 1 1/4" high. That for sure would be even more of an issue dealing with penetrations that hit on the high ribs. The Champion Metal Wide Rib panels that I am aiming to use have 7/16" high major ribs. For me it was a matter of being able to utilize existing skirting framing, which was set up for the 5/8" (?) OSB siding skirt material. There were other panels that I liked more (such as I put on my wood shed), but I realized I couldn't make them fit without re-doing the framing- a LOT of work (the framing sill plate is anchored into the concrete pad). I'm only able to get panels cut down to 36" lengths, and I only need about 29" panels: haven't decided best strategy for dealing with this, how best to optimize to minimize the cutting (as well as come out with good cuts- from the factory is going to be better than cuts that I'd be able to do).

Another issue is with penetrations. I've got a gas/propane line that'll require cutting a hole for, as well as a couple of electrical conduits. Not sure how to trim up for these: just caulk?

I'm thinking I'm going to use Z-flashing at the bottom to rest the skirting on. Figure that it might be a bit easier to keep clean this way as I'm on a concrete slab: my theory is that a meager 1/2" above the pad will make it easier to keep clean; and, I might have a little air gap to allow any backside moisture to get out (depends if I can find flashing that's just under the 7/16" mark.

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