Hi guys,
Any advise on this would be much appreciated.
We have had a warm flat roof installed on our house, the builder used the correct build up to begin with:
Joists
Ply
Vapour control layer
Insulation
However from here is where we started to encounter a possible issue..
He was going to then complete the build up with
OSB
EDPM membrane
But the flat roof needs to have a min 2 degree fall on it, so he put some firrings to create a fall between the insulation and the OSB above.
I was worried this would leave an unventilated air pocket, so asked if he could fill around the planed pieces of wood with spray foam insulation which he did, however I'm not quite confident that all of the air pockets would have been filled, on one side where the firings are thickest I can put my finger in and feel gaps so I don't think it has expanded enough to ensure there are no air gaps.
I understand the correct build up should have been:
Joists
Firrings
Ply
Vapour control layer
Insulation
OSB
EDPM membrane
So that all of the build up of the warm roof is positioned on a tilt.
But my question is, would having a gap between the insulation and the OSB cause condensation and rotting of the OSB and insulation? My builder thinks I am worrying about it too much, and I definitely don't want to cause an issue but I am worried of any issues later down the line if the build up is not completed correctly.
Any advise on this would be much appreciated.
We have had a warm flat roof installed on our house, the builder used the correct build up to begin with:
Joists
Ply
Vapour control layer
Insulation
However from here is where we started to encounter a possible issue..
He was going to then complete the build up with
OSB
EDPM membrane
But the flat roof needs to have a min 2 degree fall on it, so he put some firrings to create a fall between the insulation and the OSB above.
I was worried this would leave an unventilated air pocket, so asked if he could fill around the planed pieces of wood with spray foam insulation which he did, however I'm not quite confident that all of the air pockets would have been filled, on one side where the firings are thickest I can put my finger in and feel gaps so I don't think it has expanded enough to ensure there are no air gaps.
I understand the correct build up should have been:
Joists
Firrings
Ply
Vapour control layer
Insulation
OSB
EDPM membrane
So that all of the build up of the warm roof is positioned on a tilt.
But my question is, would having a gap between the insulation and the OSB cause condensation and rotting of the OSB and insulation? My builder thinks I am worrying about it too much, and I definitely don't want to cause an issue but I am worried of any issues later down the line if the build up is not completed correctly.
