I noticed a small hole, about 14” x 14” in our attic on the gable side. I wonder if it used to be a gable vent. Home was built in 66’

What can i do to patch this up? It looks like this sheathing material is called “blackboard” Our pest control guy said PestBlok breathable material. We could also screen it I assume. The rest of the area looks good so i don’t think it was taken out because of damage or anything.

Also, there’s some gaps in the siding along there. But the roofline seems fine. Roofing and Siding co said caulk and filler is all we need. Pest guy said drip edge installed to siding and then sealed to the chimney.

Thanks for any input! Main concern is critters making their way into the attic, and then also just don’t really want a hole in the attic, i imagine energy escapes there like crazy! Seems totally dry when it rains which is at least good.

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    Are those bricks really spray foamed in place? I don’t think I would cover it unless I knew the chimney was properly sealed.
    – Ed Beal
    Sep 13, 2019 at 18:40
  • I don’t see any spray foam present. Hope that helps!
    – rjfellman
    Sep 13, 2019 at 18:42
  • I’m wondering if in the mean time while i figure out what to do, i can at least put some hardware cloth over it so bats don’t come in.
    – rjfellman
    Sep 13, 2019 at 20:26
  • I would use hardware cloth to keep bats out, looking at the bricks it looks to me like they are filled with spray foam , if you don’t see any maybe I am wrong.
    – Ed Beal
    Sep 13, 2019 at 21:38
  • Yeah, I think that may just be the photo. It's definitely mortar in there. hardware cloth would work, I can mount to the studs. Im assuming there's more I can do but not sure what
    – rjfellman
    Sep 13, 2019 at 22:46

1 Answer 1


You don't have to worry about energy loss. Your attic floor is insulated; that's the heat barrier for the home. You even want to get heat out of your attic to prevent ice dams (assuming you're in a temperate clime), but you have a vent right next to your chimney, so you'll be fine. Critters, though, could be a problem.

I don't think it matters how you cover it up; I'd put a piece of plywood on it.

  • That's good to hear, that was also my initial thought., maybe just cut a piece to fit, put 2x4s on the side and toenail to the studs on either side. Our siding is older and I can see us replacing it in the next 3-5 years so it can be properly addressed then. I'm mostly worried about bats, and it being safe being near a chimney (stainless steel lined and has a new gas boiler attached to it and water heater) and great point about the heat loss. That seems so obvious now.
    – rjfellman
    Sep 14, 2019 at 15:23
  • If you think this is a good answer for your question, feel free to mark it as "the" answer by clicking the checkbox. Or not: your call. Sep 14, 2019 at 21:40

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