Frank69
2013-03-28 10:25:03
- #1
Hello everyone,
we bought a house, built in ’54, renovated by the previous owner.
During a conversion measure in the upper floor, I noticed a strange roof insulation and wanted to hear others’ opinions about it.
About the roof structure:
Clay roof tiles, load-bearing battens, counter battens, underlay membrane, 120 mm rafters – between these, 120 mm of rock wool was installed.
So far, that seems normal, I think, but then comes the following:
As a sort of "replacement" for the vapor barrier foil, 40 mm Styrodur C3035 was used. It was fully and cleanly applied across the sloped roof area onto the rafters, and the joints of the boards were neatly taped with green Siga Sicral tape.
At the connections to the wall, on each side a 1 cm gap was left free and sealed flush with a silicone-like black sealing compound. This stuff adheres very well to both the wall and to the Styrodur.
Then a fabric foil was applied at the transitions to the wall, which was coated with a kind of liquid plastic. On top of that, several wide strips of green Sicral tape were applied generously.
On the Styrodur then a substructure with roof battens was installed, and on top of that the Fermacell, neatly puttied.
Does this Styrodur layer fulfill the function of the otherwise usual vapor barrier?
The Styrodur was apparently added as additional insulation since 120 mm of rock wool is not really much.
The work looks very well done, like by a professional. Whether it is actually permitted that way is another question.
How does it look regarding the dew point, can the wooden structure of the roof truss become moist?
Unfortunately, I have no knowledge about this and would appreciate any opinion on the subject.
Best regards
Frank
we bought a house, built in ’54, renovated by the previous owner.
During a conversion measure in the upper floor, I noticed a strange roof insulation and wanted to hear others’ opinions about it.
About the roof structure:
Clay roof tiles, load-bearing battens, counter battens, underlay membrane, 120 mm rafters – between these, 120 mm of rock wool was installed.
So far, that seems normal, I think, but then comes the following:
As a sort of "replacement" for the vapor barrier foil, 40 mm Styrodur C3035 was used. It was fully and cleanly applied across the sloped roof area onto the rafters, and the joints of the boards were neatly taped with green Siga Sicral tape.
At the connections to the wall, on each side a 1 cm gap was left free and sealed flush with a silicone-like black sealing compound. This stuff adheres very well to both the wall and to the Styrodur.
Then a fabric foil was applied at the transitions to the wall, which was coated with a kind of liquid plastic. On top of that, several wide strips of green Sicral tape were applied generously.
On the Styrodur then a substructure with roof battens was installed, and on top of that the Fermacell, neatly puttied.
Does this Styrodur layer fulfill the function of the otherwise usual vapor barrier?
The Styrodur was apparently added as additional insulation since 120 mm of rock wool is not really much.
The work looks very well done, like by a professional. Whether it is actually permitted that way is another question.
How does it look regarding the dew point, can the wooden structure of the roof truss become moist?
Unfortunately, I have no knowledge about this and would appreciate any opinion on the subject.
Best regards
Frank