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Can a 1 1/2 story house be built to PH air sealing standards?

Cedar_Point_Builder | Posted in PassivHaus on

Specifically, how would you air seal the roof/wall/joist transitions to the second floor?

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  1. Expert Member

    Yes it can be air-sealed to PH standards. How you do that depends on what air-sealing strategy you decide on. There are vey different details for sealing at the floor depending on whether your primary air-seal is the exterior-sheathing, an interior-membrane, or the drywall.

  2. walta100 | | #2
  3. Expert Member
    Akos | | #3

    Certainly can. Keep it simple, insulate the roof, it is easy to make the air barrier continuous from exterior wall sheathing to the roof. It does mean bolt on eaves and roof with some exterior rigid insulation.

    Trying to air sealing knee walls is pointless, best avoid it.

  4. aaronbeckworth | | #4

    If a house (simple gable, steep pitch) is one story at the eaves, with exterior primary air barrier (wall sheathing taped to roof sheathing), insulation filling the rafter bays and rigid above the sheathing, that could provide a conditioned or “habitable” attic. Then interior partition walls could be built in the attic to create rooms with all sorts of configurations. Would this now be considered a 1.5 story house? Or does 1.5 story imply kneewalls at the eaves?

    Every additional foot of kneewall at the eave increases the volume of “habitable” space. But does adding kneewalls at the eaves complicate the build - structural considerations, air sealing, insulating?

  5. Cedar_Point_Builder | | #5

    I like the idea(s) of continuous exterior air sealing (probably Huber Zip) and some exterior insulation, fill the wall and rafters (probably fiberglass batts) then a vapor retarder inside (painted 5/8" sheetrock). Thanks to all.

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