tune82
2017-01-12 23:58:44
- #1
Hello everyone,
I would like to briefly introduce myself: My name is Daniel and a few days ago we purchased a house built in 1971, which we will thoroughly renovate. One of the measures is the roof.
The roofing as well as the wooden structures underneath are still in great condition, so we want to install insulation between the rafters in the upper floor (1.5 stories), the wooden beam ceiling, and possibly in the unheated attic. This whole topic poses bigger problems for me because, according to u-wert.net, condensation is to be expected.
The current roof construction from outside to inside: interlocking tiles with battens, ventilation layer (ventilation tiles at the ridge), bitumen roofing felt, 2 cm insulation, wood fiber insulation board, plaster.
The rafters need to be doubled to fit at least a 180 mm mineral wool. However, the existing bitumen membrane makes the whole assembly diffusion-tight to the outside -> consequence: condensation, because the ventilation unfortunately lies on the "wrong layer." Somehow it has to be ensured that the ventilation can also run over the insulation. A friend who is an architect said: "Just remove the bitumen membrane," but I have some concerns about moisture ingress. My idea is to selectively open the existing bitumen membrane at various points (introduce openings about 2 cm x 20 cm per meter) so that air can also flow over the insulating material and moisture can be transported away. I have attached a draft which I would like to put up for discussion.
p.s.: This is not supposed to be a permanent solution, but rather to protect me from mold and fungi for the time being (about 10 years, then a new roof will be installed) and of course also save on heating costs.
I look forward to your feedback, best regards Daniel
I would like to briefly introduce myself: My name is Daniel and a few days ago we purchased a house built in 1971, which we will thoroughly renovate. One of the measures is the roof.
The roofing as well as the wooden structures underneath are still in great condition, so we want to install insulation between the rafters in the upper floor (1.5 stories), the wooden beam ceiling, and possibly in the unheated attic. This whole topic poses bigger problems for me because, according to u-wert.net, condensation is to be expected.
The current roof construction from outside to inside: interlocking tiles with battens, ventilation layer (ventilation tiles at the ridge), bitumen roofing felt, 2 cm insulation, wood fiber insulation board, plaster.
The rafters need to be doubled to fit at least a 180 mm mineral wool. However, the existing bitumen membrane makes the whole assembly diffusion-tight to the outside -> consequence: condensation, because the ventilation unfortunately lies on the "wrong layer." Somehow it has to be ensured that the ventilation can also run over the insulation. A friend who is an architect said: "Just remove the bitumen membrane," but I have some concerns about moisture ingress. My idea is to selectively open the existing bitumen membrane at various points (introduce openings about 2 cm x 20 cm per meter) so that air can also flow over the insulating material and moisture can be transported away. I have attached a draft which I would like to put up for discussion.
p.s.: This is not supposed to be a permanent solution, but rather to protect me from mold and fungi for the time being (about 10 years, then a new roof will be installed) and of course also save on heating costs.
I look forward to your feedback, best regards Daniel