Hello,
we have purchased an old house where the roof is currently insulated with aluminum-coated insulation wool placed between the rafters.
The roof tiles are laid on wooden battens. In the upper roof area, there is a ventilation tile installed in each rafter bay.
We would like to re-insulate the roof from the inside because the old insulation is partly falling out and torn.
However, the roof will only be re-covered in 5-8 years.
My question is whether it makes sense to install 120mm (5 inches) of insulation batts between the rafters (rafter height is 140mm (5.5 inches)) plus an additional 50mm (2 inches) of insulation below the rafters,
or if it would be better to double the rafters and install 180mm (7 inches) of insulation batts from the inside.
In both cases, of course, with an interior vapor control layer and an appropriate finish with drywall/plasterboard (Rigips/Fermacell).
The idea would then be to add further insulation from the outside later with a wood fiberboard when the roof is replaced.
Thank you very much in advance. Best regards from the North
we have purchased an old house where the roof is currently insulated with aluminum-coated insulation wool placed between the rafters.
The roof tiles are laid on wooden battens. In the upper roof area, there is a ventilation tile installed in each rafter bay.
We would like to re-insulate the roof from the inside because the old insulation is partly falling out and torn.
However, the roof will only be re-covered in 5-8 years.
My question is whether it makes sense to install 120mm (5 inches) of insulation batts between the rafters (rafter height is 140mm (5.5 inches)) plus an additional 50mm (2 inches) of insulation below the rafters,
or if it would be better to double the rafters and install 180mm (7 inches) of insulation batts from the inside.
In both cases, of course, with an interior vapor control layer and an appropriate finish with drywall/plasterboard (Rigips/Fermacell).
The idea would then be to add further insulation from the outside later with a wood fiberboard when the roof is replaced.
Thank you very much in advance. Best regards from the North
N
nix zu schwör30 Oct 2019 19:01The roofer is not wrong, as the moisture protection verification can only be calculated using specialized software, while the thermal insulation verification often only requires a standard Glaser method assessment.
Double drywall is used for two reasons:
the drywall is installed on a flexible wooden structure that is subject to pressure and suction forces
and also to provide ventilation for summer heat protection
Double drywall is used for two reasons:
the drywall is installed on a flexible wooden structure that is subject to pressure and suction forces
and also to provide ventilation for summer heat protection
If anything, you would use a vapor retarder, not a vapor barrier. However, my nephew, who is a carpenter by trade, thinks highly of this climate membrane and recommended it to us despite the higher cost. Whether you spend 45 or 85 euros on the foil doesn’t really matter when the total is 1500 euros. The installation process for both types of foil is the same. Being airtight is crucial. Completely airtight with no gaps. We sealed the membrane overlaps with tape and adhered the foil to the floors and walls using an adhesive compound. The adhesive sets quickly and sticks very well, while the tape is extremely strong—once it touches the surface, it bonds firmly.
Nordlys schrieb:
If anything, you would use a vapor retarder, not a vapor barrier. But my nephew, a carpenter by trade, thinks highly of this climate membrane and recommended it to us despite the extra cost. Whether you spend 45 or 85 euros for the membrane, it doesn’t really matter when the total is 1500,- anyway. The installation process for both membranes is the same. Airtightness is crucial—completely airtight. We sealed the membrane overlaps with tape and glued the membrane to the floors and walls using adhesive sealant. The sealant sets quickly and bonds very well; the tape is tricky—it sticks firmly on contact. Which exact membrane did you use?
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