The company Pavatex (as well as other manufacturers of wood fiber insulation materials) offers a renovation solution for roofs that eliminates the need for a vapor retarder membrane.
Only the interior cladding needs to have a certain degree of vapor-retarding properties.
The airtightness of the system is achieved by installing a special highly vapor-permeable membrane (0.02), which is applied flat over the rafters (i.e., above the insulation between the rafters, which consists of wood fiber soft boards).
Above this airtight membrane, an insulation layer of at least 35 mm (1.4 inches) wood fiber boards must be installed.
According to the manufacturer, the wood fiber insulation is so vapor-permeable that any moisture that might occur is quickly transported outward.
Pavatex argues that this construction method is more tolerant of errors than a conventional setup using a vapor retarder membrane applied in a staggered (overlapping) manner, as this is difficult to execute properly in older buildings.
Are there any practical experiences with this?
Regards
Only the interior cladding needs to have a certain degree of vapor-retarding properties.
The airtightness of the system is achieved by installing a special highly vapor-permeable membrane (0.02), which is applied flat over the rafters (i.e., above the insulation between the rafters, which consists of wood fiber soft boards).
Above this airtight membrane, an insulation layer of at least 35 mm (1.4 inches) wood fiber boards must be installed.
According to the manufacturer, the wood fiber insulation is so vapor-permeable that any moisture that might occur is quickly transported outward.
Pavatex argues that this construction method is more tolerant of errors than a conventional setup using a vapor retarder membrane applied in a staggered (overlapping) manner, as this is difficult to execute properly in older buildings.
Are there any practical experiences with this?
Regards