There is a lot of condensation in the loft. It is a cold roof, with tiles on battens on membrane over rafters. Insulation in between and under rafters.
Water condenses on the inside surface of the membrane. The membrane is Tyvek Supro and is 100% water proof. And costs a bomb.
This happens on "warm" mornings after very cold nights. It happened last winter, and it happened again a few days ago where during one night the temps dropped to 2C.
Initially I thought there was not enough ventilation under the membrane. But there are plenty of unfinished sections, no insulation and membrane visible, and yet, it still condenses a lot of water. To improve ventilation I did open the membrane at the top ridge but this has not fixed the problem.
To make matters worse, even though we must allow ventilation in between rafters, there are many places where the paths are completely blocked, due to roof construction, eg dormers, hips, valleys, noggins etc.
This is like leaving a cold drink on the table, after half an hour the table is drenched. The hygrometer registered 96% humidity the other day when I placed that cold bottle of coke on the table, air temp was 11C. Humid air exists all around us, as can be seen in the mornings where everything outside is soaked, I cannot prevent humid air from reaching cold spots, especially the underside of the membrane.
What I have seen it, so far, has only happened on the north side of the roof.
If there is a solution, please let me know if I have missed something.
Water condenses on the inside surface of the membrane. The membrane is Tyvek Supro and is 100% water proof. And costs a bomb.
This happens on "warm" mornings after very cold nights. It happened last winter, and it happened again a few days ago where during one night the temps dropped to 2C.
Initially I thought there was not enough ventilation under the membrane. But there are plenty of unfinished sections, no insulation and membrane visible, and yet, it still condenses a lot of water. To improve ventilation I did open the membrane at the top ridge but this has not fixed the problem.
To make matters worse, even though we must allow ventilation in between rafters, there are many places where the paths are completely blocked, due to roof construction, eg dormers, hips, valleys, noggins etc.
This is like leaving a cold drink on the table, after half an hour the table is drenched. The hygrometer registered 96% humidity the other day when I placed that cold bottle of coke on the table, air temp was 11C. Humid air exists all around us, as can be seen in the mornings where everything outside is soaked, I cannot prevent humid air from reaching cold spots, especially the underside of the membrane.
What I have seen it, so far, has only happened on the north side of the roof.
If there is a solution, please let me know if I have missed something.