rafter insulation

Hello,

I am planning to convert my attic and wanted to insulate the rafters with 8cm wood fiberboard and cellulose. Do I have to leave a ventilation gap between the vapor barrier (outside) and the wood fiberboard (inside) or can I clamp it tightly against the barrier between the rafters???

Thank you very much in advance!

Hello,

Leaving a space for ventilation is certainly a clever step.
I would prefer the isofloc insulation with cellulose.
It has often proven to be reliable.

Regards

Hello,

I am planning to convert my attic and wanted to insulate the rafters with 8cm wood fiberboard and cellulose. Do I have to leave space for ventilation between the vapor barrier (outside) and the wood fiberboard (inside), or can I clamp it tightly against the barrier between the rafters???

Thank you in advance!

Hello,

will the roof be stripped and rebuilt?

Best regards

K.Brodbeck

Hello,
the roof will not be uncovered and will remain as it is because it is new. I only decided later to convert it, otherwise I would of course have used the wood wool fiberboards as exterior insulation. But now it is different and I want to install the wood wool fiberboards from the inside. The question remains: air gap or not?????
Best regards, Thomas Riepen

Hello,
the roof will not be uncovered and remains as it is because it is new. I only decided later to expand after all, otherwise I would have of course used the wood fiberboard panels as over-rafter insulation. But now it is different and I want to install the wood fiberboard panels from the inside. The question remains: air gap or not?????
Best regards, Thomas Riepen

Hello,

the air gap is a nice idea, but it is just an air gap as long as there is no ventilation in the eaves and ridge area.

In my case, I also choose a solution with wood fiberboard panels cut between the rafters. However, our roof is already 80 years old and will probably have to be renewed in the foreseeable future, so I can then pull the underroof over the rafters. This method is an emergency solution that I would not carry out on a newly built roof (because it is an 'eternal' provisional solution).

best regards

K.Brodbeck