Vapor barrier under loft?

[Uvberget]

Hi, we are building an attefallshus and will have a bathroom under the part that becomes a loft. Should I install a vapor barrier in the bathroom ceiling? There is a vapor barrier installed in the rest of the house.

 

[Jonatan79]

Yes, to prevent moisture from rising and getting trapped in the intermediate floor structure, for example.

 

[byggarätt]

Hello, we are building an attefallshus and will have a bathroom under the section that will be a loft. Should I put a vapor barrier in the bathroom ceiling? There is a vapor barrier installed in the rest of the house.

What type of insulation is in the house?
It's important to have the right moisture barrier for each type of insulation!
The answer to your question depends on whether you have insulation in the joists for the sleeping loft.
Bathrooms must be ventilated and have a moisture barrier that stops the moisture until it is ventilated out, so if you have supply air and ventilation, construction plastic and wet room gypsum in the bathroom ceiling will suffice!
To avoid hearing bathroom sounds in the sleeping loft, you can soundproof, but in such a small house, sound will come through the door gap and bathroom wall.

 

[Daniel 109]

It is appropriate to have something that slows down a bit. But it is probably not necessary when there is a heated space above the ceiling. As long as there are no gaps.

 

[ByggPajken]

No. But you paint the ceiling with a dense paint.

 

[useless]

What type of insulation is in the house? It's important to have the right moisture barrier for each type of insulation! The answer to your question depends on whether you have insulation in the floor structure to the sleeping loft. Bathrooms must be ventilated and have a moisture barrier that stops moisture until it is ventilated out, so if you have incoming air and ventilation, building plastic wet room gypsum in the ceiling of the bathroom is sufficient! To avoid hearing bathroom sounds to the sleeping loft, you can soundproof, but in such a small house, sound will come through the door gap and bathroom wall.

Since the temperature is the same on both sides in this case, the choice of moisture barrier isn't so critical which type of moisture barrier you choose. The important thing is that the moisture is kept on the right side.