Hi there,
I'm in the process of creating a room in my loft area and need to add vents near to the ridge and top of the hips to enable air flow behind the insulation. It is a 1940's semi detached house with a hip roof, an unventilated cold roof design, and non permeable sarking.
The room will only be used occasionally via a loft hatch so no need for meeting building control u-values etc.
The insulation will be 40mm celotex placed between the rafters with a further 40mm below the rafters. A 50mm gap will be left between the insulation and the sarking for airflow. I'll foil tape the celotex together to form a vapor barrier between the room and the roof and finally plasterboard to finish. I'll also be adding over fascia vents to enable air flow from below.
For the high level vents, it would require 48 individual tile vents between each rafter so it looks like using a ventilated dry ridge/hip system is the way to go.
But before I purchase one I wanted to know if it was feasible to use lap vents as an alternative to the ventilated dry ridge system?
If no (which is which is the answer I expect), then will I be able to re-use the existing half round ridge and arris hip tiles when using a dry ridge/hip system? or will I have to purchase the plastic ones that they use in their demonstration videos?
Many thanks in advance.
Paul
I'm in the process of creating a room in my loft area and need to add vents near to the ridge and top of the hips to enable air flow behind the insulation. It is a 1940's semi detached house with a hip roof, an unventilated cold roof design, and non permeable sarking.
The room will only be used occasionally via a loft hatch so no need for meeting building control u-values etc.
The insulation will be 40mm celotex placed between the rafters with a further 40mm below the rafters. A 50mm gap will be left between the insulation and the sarking for airflow. I'll foil tape the celotex together to form a vapor barrier between the room and the roof and finally plasterboard to finish. I'll also be adding over fascia vents to enable air flow from below.
For the high level vents, it would require 48 individual tile vents between each rafter so it looks like using a ventilated dry ridge/hip system is the way to go.
But before I purchase one I wanted to know if it was feasible to use lap vents as an alternative to the ventilated dry ridge system?
If no (which is which is the answer I expect), then will I be able to re-use the existing half round ridge and arris hip tiles when using a dry ridge/hip system? or will I have to purchase the plastic ones that they use in their demonstration videos?
Many thanks in advance.
Paul
