Insect screen for an exterior rigid foam wall
I live in the San Francisco bay area and am going to use 1-1/2″ rigid foam board and a rain screen on the exterior of my house. I have read numerous articles in regards to using insect screen at the tops and bottoms of the rainscreen wall, however no specific details about the type of insect screen is ever mentioned.
There are numerous types of insect screens (Aluminum, Fiberglass Bronze, galvanized, etc.) available. There are also different mesh configurations.
Do any of you have experience or suggestions for a particular type and mesh that works well with a raincreen (or perhaps maybe I am overthinking this issue).
Thanks for any comments.
Randy Mason
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Replies
All houses here have to be built with rain screens. No one uses insect screen anymore, it is too easily damaged and then is impossible to replace. Use a U shaped perforated metal flashing you can slip over the bottom of your rain screen strapping, or in the case of exterior foam, over the foam and strapping. Keeps both bugs and rodents out.
Something like this:
http://www.menzies-metal.com/vent-flashings/perforated-j-channel-rain-screen-high-back
I'm going to revive this because I'm curious what everyone is using?
Planning to use Cor-A-Vent for my upcoming build
We purchase 4x8 sheets of 0.032g perforated aluminum which we cut and bend on our aluminum brake to fit the desired insulation and rainscreen assembly.
We have found this to be cost-effective and very simple to install.
If you want to use window screen, avoid aluminum -- it tends to rot out fairly quickly when exposed to wet debris splashing up from the ground. Fiberglass will last longer, but is less critter resistant, so you have more risk of critters chewing through it. I have not use galvanized screen. My perference is 316 stainless steel screen, which is durable and will last a long time.
If you can use one of the channel products such as the one Malcolm suggested, that's another good option, and probably easier to install than screen.
Bill
Any chance you have found any good suppliers of this in the Metro Detroit area? Coravent seems very expensive and not that useful. Seeing the Jake Burton video, it sounds like he skips the bug screen entirely, that might be the way to go. Or just some simple stainless window screen type of material.
Tim,
There might be a case for not using insect screen in some climates if the cavity was directly against the sheathing, but with exterior foam that's asking for something to go in there and tunnel.
This is a piece of foam I took off the roof of a house with a carpenter ant infestation
In my case, I'm using 3/4" buttons directly over sheathing. WRB in there as well.
Hard to quantify the thermal bridging from carpenter ants!
Tim,
I have a friend who is a builder in Manitoba. The first rain-screen he did he found was quickly clogged with thousands of Ladybugs. No screens probably would have avoided that. What works seems quite climate dependent.
I could see that. We got swarms of lady bugs back in Illinois. Talking with my framer and builder, we are going to opt to just use screen material. I'll peel off a siding board in a decade and report back.