We have a turn-of-the-century house where we will build a bathroom on the 2nd floor. Above this is a cold attic with sawdust insulation. We will install an exhaust fan in the bathroom (Pax or similar). The house is used as a summer house.
The current ceiling is plank, and above it (the attic) is newspaper and sawdust.
My idea is, in addition to the fan, to place a vapor barrier in the ceiling to reduce moisture to the attic, and I see two options.
The simple one: place the vapor barrier (fabric) on the plank ceiling from below and then drywall with waterproof paint. So looking up from below: drywall, vapor barrier, plank, newspaper, sawdust.
The more difficult way: go up to the attic, shovel away sawdust, place vapor barrier on the plank ceiling. Then paint the plank ceiling in the bathroom or possibly install drywall. So, looking up from below: possibly drywall, plank, vapor barrier, newspaper, sawdust.
Is option 1 okay, or do I need to go into the attic?
The current ceiling is plank, and above it (the attic) is newspaper and sawdust.
My idea is, in addition to the fan, to place a vapor barrier in the ceiling to reduce moisture to the attic, and I see two options.
The simple one: place the vapor barrier (fabric) on the plank ceiling from below and then drywall with waterproof paint. So looking up from below: drywall, vapor barrier, plank, newspaper, sawdust.
The more difficult way: go up to the attic, shovel away sawdust, place vapor barrier on the plank ceiling. Then paint the plank ceiling in the bathroom or possibly install drywall. So, looking up from below: possibly drywall, plank, vapor barrier, newspaper, sawdust.
Is option 1 okay, or do I need to go into the attic?
I'm not going to say I have 100% on track.
But I would have gone with option 1 with a humidity-controlled exhaust fan.
One of my bathrooms has a patchwork vapor barrier after various renovations, but there are no signs of moisture problems there.
A gypsum ceiling painted with wet room paint and sealed against the walls and an exhaust fan in the ceiling feels in theory very tight.
But I would have gone with option 1 with a humidity-controlled exhaust fan.
One of my bathrooms has a patchwork vapor barrier after various renovations, but there are no signs of moisture problems there.
A gypsum ceiling painted with wet room paint and sealed against the walls and an exhaust fan in the ceiling feels in theory very tight.
Alternative 1 makes sense. Already plaster with color would probably go a long way. But it's not wrong to have a vapor barrier there.