Bugs under metal roof
I am building a shop right now and plan to put an exposed-fastener metal roof on it. The attic is open, and the insulation will be between the rafters. I’m about to install a metal roof. My plan is to install it over cross battens to keep the steel ventilated and reduce heat inside the building.
I am having a difficult time deciding on what to do about ventilating the eaves. I know that in a rainscreen wall application, screening the bottom is important to keep out insects like wasps. I am wondering if this is necessary with a roof which, on a sunny day, likely exceeds 40-50 degrees. I may get some bugs up there now and then but this seems too hostile an environment to encourage a serious pest problem(?) Perhaps this is a question best posed to an entomologist, but I would appreciate any input.
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Replies
I’d put in bug protection now while you have easy access. I don’t know how hot it can be before the heat drives the bugs out, but I’ve seen hornet nests inside attics that routinely get up to 120F+.
Bill
I agree with Bill - I've had bees and wasps in attics in Arizona and Michigan. Heat doesn't seem to bother them much.
I think it takes about 55C to kill them.
Maybe the other question is: why would you not screen? If the screen is heavy enough gauge, it can keep out a pretty wide variety of pests that you may not even want "exploring" that space.
And in areas with wildfire concerns, you can select a heavy enough gauge to keep brands and embers out of this space. I believe the right mesh for this is 1/4-inch mesh 26 gauge.
Peter