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insulating a 1970 house

CircuitGeek

Member
Joined
May 8, 2025
Messages
15
City & State/Province
Virginia
My family has this '70 house with a brick skin, you know, with those weep holes.

Then there's about an inch of air, followed by this asphalt lined fiberboard with nothing in between before the drywall.

I want to pump in some insulation so I don't have to tear down all the drywall. I know what a headache that would be!

I'm in zone 8, and my main worry is stirring up any moisture problems. Will I be in the clear if I go ahead with this? What's the lay of the land here?
 
Insulation blown into the wall cavity should work just fine, in my opinion. The installation of the vapor barrier or retarder, not the insulation itself, is typically the cause of the majority of moisture problems. Although I haven't done a lot of work with asphalt fiberboard, you should be fine if your walls can breathe from both sides.
 
No don't fill the air gap, it's there to prevent moisture issues, instead, insulate between the fiberboard and drywall with something like dense pack cellulose. That way, you boost insulation without risking moisture problems
 
Absolutely! Maintaining that air gap is essential for managing moisture effectively. Using dense pack cellulose is a clever choice, it allows for breathability in that area.
 
Yeah, do not mess with that air gap behind the brick. It's actually doing you a favor like they're all saying here. Dense pack between the fiberboard and drywall should keep you comfortable. Seal what needs to be sealed tho.
 
Moisture isn't usually a big deal in Zone 8. Still, it's a good idea to look for any water problems now. For insulation, blown cellulose or fiberglass should do the trick in that space. And don't forget to keep those weep holes open
 
You're definitely going to want to drill some access holes in the drywall. Usually every 16" between the studs. Those holes are very easy to patch up later.
 
Avoid too much insulation without proper vapor control, you might get condensation in your walls
 
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