Isolering (hus 1925)
Hi ,
Sorry for writing in english but my Swedish is not very good.
I have removed the glass fiber that was on the ceiling of the 2nd floor and will install a new insulation under the roof of our old villa (built 1925)
I have left 2 cm air layer between the roof boards and the new insulation and i will install as well a new vapour barrier.
1/ Should i close the ventilation (small opening ) at the lower part of the roof?
I was told that this type of "ventilated" air layer technique was used in the old houses but that nowdays it is proven that it has negative effect as the "cold and humid" air from outside is circulating under the roof board?
2/ If i keep the ventilated air layer (as it is now) , can i use an active vapour membrane (variable Sd)? or should i just use the normal blue "byggfolie" ?
Many thanks in advance
Mathias
Sorry for writing in english but my Swedish is not very good.
I have removed the glass fiber that was on the ceiling of the 2nd floor and will install a new insulation under the roof of our old villa (built 1925)
I have left 2 cm air layer between the roof boards and the new insulation and i will install as well a new vapour barrier.
1/ Should i close the ventilation (small opening ) at the lower part of the roof?
I was told that this type of "ventilated" air layer technique was used in the old houses but that nowdays it is proven that it has negative effect as the "cold and humid" air from outside is circulating under the roof board?
2/ If i keep the ventilated air layer (as it is now) , can i use an active vapour membrane (variable Sd)? or should i just use the normal blue "byggfolie" ?
Many thanks in advance
Mathias
