Hello everyone,
We are currently renovating an old building (built in 1958) and the topic is the suspended ceiling in the bathroom.
The construction is a bit unusual: the bathroom is on the ground floor, but there is no room above it, just a rather shallow roof slope. Originally, we just removed the existing ceiling, hoping to install a new, higher suspended ceiling. However, this hope was dashed by a massive concrete beam. So now, a stretch ceiling or drywall ceiling will be installed back in the original position.
At least we now have the chance to improve the insulation. The old setup was:
straw ceiling -> thin glass wool insulation -> thick glass wool insulation -> roof.
We don’t know exactly how the roof is insulated, but at least a membrane is visible on the underside of the roof.
My idea now is to add insulation between the rafters below the thick glass wool (there are wooden beams that fit well for this) and then cover it with a membrane for protection. What I’m not clear about is whether the membrane should be installed as a vapor barrier, sealed as airtight as possible, or not sealed airtight at all.
Since the previous construction was quite vapor-permeable and there have been no issues so far, I tend to think the membrane should not be sealed airtight either.
What do you think? Or do you have other suggestions?
Best regards,
Tobias
We are currently renovating an old building (built in 1958) and the topic is the suspended ceiling in the bathroom.
The construction is a bit unusual: the bathroom is on the ground floor, but there is no room above it, just a rather shallow roof slope. Originally, we just removed the existing ceiling, hoping to install a new, higher suspended ceiling. However, this hope was dashed by a massive concrete beam. So now, a stretch ceiling or drywall ceiling will be installed back in the original position.
At least we now have the chance to improve the insulation. The old setup was:
straw ceiling -> thin glass wool insulation -> thick glass wool insulation -> roof.
We don’t know exactly how the roof is insulated, but at least a membrane is visible on the underside of the roof.
My idea now is to add insulation between the rafters below the thick glass wool (there are wooden beams that fit well for this) and then cover it with a membrane for protection. What I’m not clear about is whether the membrane should be installed as a vapor barrier, sealed as airtight as possible, or not sealed airtight at all.
Since the previous construction was quite vapor-permeable and there have been no issues so far, I tend to think the membrane should not be sealed airtight either.
What do you think? Or do you have other suggestions?
Best regards,
Tobias
Schimi179122 Dec 2020 15:01I would tend to recommend a vapor retarder that is installed professionally. We used the Isover Vario KM Duplex UV and have had no issues so far.
T
Trademark22 Dec 2020 22:08No vapor barrier, but a vapor retarder as Schimi suggests. This way, the assembly remains vapor-permeable. Still, it must be installed professionally to ensure airtightness. That’s how you regulate moisture.
Another question: Is there anything between the roof and the glass wool insulation? Or do the roof tiles go directly on top?
Another question: Is there anything between the roof and the glass wool insulation? Or do the roof tiles go directly on top?
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