Hello everyone,
I want to renovate my attic, which is already being used as living space. The somewhat outdated paneling will partially be removed. I took down the paneling in one room, and as expected, there wasn’t much insulation between the rafters (built in 1974). The rafters are 160mm (6.3 inches) wide, with 6-8cm (2.4-3.1 inches) of aluminum foil-backed glass wool insulation in between. There is neither a vapor barrier on the interior side nor a breathable roofing membrane on the exterior side—behind the glass wool you can directly see the roof tiles (of course, on battens ;-) ).
So I went to a building materials supplier for advice and quotes. The general consensus was to install 140mm (5.5 inches) of insulation between the rafters, include a 2cm (0.8 inches) ventilation gap on the outside because of the missing roofing membrane, then a vapor retarder, followed by counter battens, and insert another 40-50mm (1.6-2 inches) of insulation between those before finally adding the ceiling cladding, which in my case will no longer be wood but drywall.
What do you think of this setup?
One idea I have is to double the rafters inward using an old panel board (1.5cm / 0.6 inches) to create more depth for 160mm (6.3 inches) of insulation, while still allowing for a ventilation space of about 1.5cm (0.6 inches). Does that make sense?
Another issue I suspect is in the knee wall area. In my case, this is a masonry wall. What should I do here? I can’t insulate behind this knee wall with my rafter insulation, nor can I install a vapor retarder because the wall extends between the rafters. I was thinking of attaching the vapor retarder directly to the wall using a special adhesive cartridge. Or does this only make sense if the insulation goes behind the knee wall as well? That would mean removing the knee wall first, then rebuilding it, which would be more expensive. Also, I would need to do most of it at once and can’t really work room by room or spread it out over time for financial reasons.
I appreciate any advice.
Best regards,
woha
I want to renovate my attic, which is already being used as living space. The somewhat outdated paneling will partially be removed. I took down the paneling in one room, and as expected, there wasn’t much insulation between the rafters (built in 1974). The rafters are 160mm (6.3 inches) wide, with 6-8cm (2.4-3.1 inches) of aluminum foil-backed glass wool insulation in between. There is neither a vapor barrier on the interior side nor a breathable roofing membrane on the exterior side—behind the glass wool you can directly see the roof tiles (of course, on battens ;-) ).
So I went to a building materials supplier for advice and quotes. The general consensus was to install 140mm (5.5 inches) of insulation between the rafters, include a 2cm (0.8 inches) ventilation gap on the outside because of the missing roofing membrane, then a vapor retarder, followed by counter battens, and insert another 40-50mm (1.6-2 inches) of insulation between those before finally adding the ceiling cladding, which in my case will no longer be wood but drywall.
What do you think of this setup?
One idea I have is to double the rafters inward using an old panel board (1.5cm / 0.6 inches) to create more depth for 160mm (6.3 inches) of insulation, while still allowing for a ventilation space of about 1.5cm (0.6 inches). Does that make sense?
Another issue I suspect is in the knee wall area. In my case, this is a masonry wall. What should I do here? I can’t insulate behind this knee wall with my rafter insulation, nor can I install a vapor retarder because the wall extends between the rafters. I was thinking of attaching the vapor retarder directly to the wall using a special adhesive cartridge. Or does this only make sense if the insulation goes behind the knee wall as well? That would mean removing the knee wall first, then rebuilding it, which would be more expensive. Also, I would need to do most of it at once and can’t really work room by room or spread it out over time for financial reasons.
I appreciate any advice.
Best regards,
woha
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