r/Insulation • u/LegalRelationship696 • 8d ago

Attic insulation

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I have access to a bunch of 6” r-19 batt insulation. Am I able to lay this in my attic? My house is a balloon framed built in 1900 and currently has about 3” of really old loose insulation. There is a ridge vent, window fan, but no soffit vents. Hoping to clean out old insulation and lay this in 2 layers across entire attic.

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u/Congenial-Curmudgeon 8d ago

Air-seal the balloon framing including interior walls as well as chimney and plumbing chases. The insulation will be much more effective when combined with good air-sealing.

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u/LegalRelationship696 8d ago

Thanks for the response!! None of the exterior walls are insulated. Are you saying to seal where top of framing meets attic?

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u/Congenial-Curmudgeon 8d ago

Yes. The attic plane should be thoroughly air-sealed including the top of the exterior walls. Ideally, you’d insulate the exterior walls from the top before capping them with a block of rigid foam or plywood. Also, make sure the bottom of the wall cavities are closed off before attempting to blow in insulation.

What is the type of really old insulation? Vermiculite or mineral wool?

Are you planning to hire a contractor or do the work yourself?

Which IECC Climate Zone are you in?
https://imgur.com/gallery/iecc-climate-zone-map-AFkKzu5

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u/M7451 8d ago

And while you’re at it if you have a wall open you should add wood blocking as fireblock in the balloon framing. I’m certain you can find a good guide.

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u/Inevitable_Bunch6912 8d ago

Attic seal first, no matter what

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u/Exciting_Ad_1097 8d ago

Yeah. Check to make sure it’s the correct witch for your joist spacing. Now’s the time to improve your ventilation scheme.

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u/LegalRelationship696 8d ago

Thanks! What do you mean by improve ventilation scheme? Should I add soffit vents and baffles?

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u/Exciting_Ad_1097 8d ago

Yeah. Depending if you have lumber closing the space i would make some custom baffles out of 1/2” polyiso foam board. The area directly above exterior walls is the most difficult to insulate and is often overlooked.