Air gap above insulation
Posted: Tue Feb 19, 2013 3:37 pm
Hi
I am looking for some advice on installing insulation in the eaves of my house. It's a bit of a complicated setup so will do my best to explain.
The ceiling below my loft space is not horizontal across the whole of the ceiling. Where the ceilings meet the outside wall there is a 45 degree slope of about 1 foot. Currently the loft space is insulated above the horizontal part of the ceiling only. This is causing issue in that the 45 degree section of the ceilings are not insulated, making them colder than the rest of the ceiling. Due to this, condensation is forming on them and they have mildew growing on them.
The problem I have is that the area above the 45 degree sections of the ceiling is hard to get access to and is a tight space. The space between the top of the lathing and the underside of the tiles is only the depth of the rafters (approx 100mm). I had previously read that an air gap is required at the eaves of 50mm between the top of the insulation and the underside of the tiles. I went and bought a load of spacers specifically to keep an air gap between some rockwool insulation and the underside of the tiles. However, due to the ceiling joists meeting the rafters right at the entrance to this small space I have found it practically impossible to get the spacers and insulation into place whilst maintaining the air gap.
I have since read that no air gap is required if the tiles have no felt on the underside (as is the case in my house) as the roof space is naturally breathable due to the small gaps between the tiles. So, after a long-winded explanation, I am wanting to know if anyone can recommend on whether this would be the case in my situation?
Thanks in advance for the advice.
I am looking for some advice on installing insulation in the eaves of my house. It's a bit of a complicated setup so will do my best to explain.
The ceiling below my loft space is not horizontal across the whole of the ceiling. Where the ceilings meet the outside wall there is a 45 degree slope of about 1 foot. Currently the loft space is insulated above the horizontal part of the ceiling only. This is causing issue in that the 45 degree section of the ceilings are not insulated, making them colder than the rest of the ceiling. Due to this, condensation is forming on them and they have mildew growing on them.
The problem I have is that the area above the 45 degree sections of the ceiling is hard to get access to and is a tight space. The space between the top of the lathing and the underside of the tiles is only the depth of the rafters (approx 100mm). I had previously read that an air gap is required at the eaves of 50mm between the top of the insulation and the underside of the tiles. I went and bought a load of spacers specifically to keep an air gap between some rockwool insulation and the underside of the tiles. However, due to the ceiling joists meeting the rafters right at the entrance to this small space I have found it practically impossible to get the spacers and insulation into place whilst maintaining the air gap.
I have since read that no air gap is required if the tiles have no felt on the underside (as is the case in my house) as the roof space is naturally breathable due to the small gaps between the tiles. So, after a long-winded explanation, I am wanting to know if anyone can recommend on whether this would be the case in my situation?
Thanks in advance for the advice.