Hi guys,
Thanks for your time.
Its more a is this okay rather will this be okay as its complete now.The peace of mind would be nice though
Hear me out please. Mono pitched roof, cross battened, breathable membrane and 8" rafters. I want downlights. Building control stated no holes in insulation and recommended 4" insulation with 1" overboarding. They went away and myself and the builder agreed the following solution to allow us to fit downlights but not compromise insulation.
Please see pictures. We have left a 1.5" gap between the breathable membrane and the 4" insulation, we then have a 2.5" gap to the bottom of the rafters and then the 1" overboarded insulation which is foil taped and are joined to the Velux vapour barrier to form a complete vapour barrier. I'm aware drilling the holes for the downlights will compromise this somewhat.
My concern is the 2.5" gap and moist air getting into this space. The moist air will hit warm air anyways as its in essence sandwiched between insulation. From here if it gets past the 4" insulation there is a 1.5" void ventilated by eaves vents and the breathable membrane which above is cross battended so has full ventilation up the cross battens.
Im telling myself this isnt going to be a problem. Am I correct?
Thanks for any advice.
Thanks for your time.
Its more a is this okay rather will this be okay as its complete now.The peace of mind would be nice though
Hear me out please. Mono pitched roof, cross battened, breathable membrane and 8" rafters. I want downlights. Building control stated no holes in insulation and recommended 4" insulation with 1" overboarding. They went away and myself and the builder agreed the following solution to allow us to fit downlights but not compromise insulation.
Please see pictures. We have left a 1.5" gap between the breathable membrane and the 4" insulation, we then have a 2.5" gap to the bottom of the rafters and then the 1" overboarded insulation which is foil taped and are joined to the Velux vapour barrier to form a complete vapour barrier. I'm aware drilling the holes for the downlights will compromise this somewhat.
My concern is the 2.5" gap and moist air getting into this space. The moist air will hit warm air anyways as its in essence sandwiched between insulation. From here if it gets past the 4" insulation there is a 1.5" void ventilated by eaves vents and the breathable membrane which above is cross battended so has full ventilation up the cross battens.
Im telling myself this isnt going to be a problem. Am I correct?
Thanks for any advice.
