- Joined
- 7 Feb 2010
- Messages
- 3,006
- Reaction score
- 332
- Country
I understand the difference in construction between a warm (flat) roof and a cold roof. I've insulated both (cold and ventilated in the case of a loft conversion - ok, not flat but the same principle), and warm in the case of an outbuilding renovation.
But I'm having a rush of blood to the brain, I think. ... sitting here today, I can't get my head round the need for ventilation in a cold, flat roof, with an intact vapour barrier above the plasterboard. If warm moist air can't rise into the roof from below, and condense, and the roof covering is also intact, how can moisture get into the timber of the roof structure, and need to be ventilated away? What's the issue with packing the insulation between the joists, up against the top deck?
Sigh.
Cheers
Richard
But I'm having a rush of blood to the brain, I think. ... sitting here today, I can't get my head round the need for ventilation in a cold, flat roof, with an intact vapour barrier above the plasterboard. If warm moist air can't rise into the roof from below, and condense, and the roof covering is also intact, how can moisture get into the timber of the roof structure, and need to be ventilated away? What's the issue with packing the insulation between the joists, up against the top deck?
Sigh.
Cheers
Richard