Okay, odd one here. Disclaimer first, I'm an English builder/carpenter but now living in a very cold climate (Norway). The issue is with my own house (thankfully, would hate it if it'd been a customer!).
Once every few years (this is the third time in 14 years) my kitchen ceiling will 'leak'... So far I've collected about 3L of mucky water.
The timber framed house has an almost flat roof with a small air space over. I.e. a few cm/inches at the front, angling up to about 45cm/18" at the back. Barely big enough for someone to 'commando' crawl into.
I've cut a hole in the cladding on the 'high' side and can see into this 'roof' space; the underside of the roof sheathing is all bone dry.
Roughly in the area where it's leaking I can see a dark patch on the felt which runs across the top of the ceiling joists and insulation (it's about 20'/6m away, so difficult to see 100% clearly). There also seems to be a slight dip in the felt at this location.
My working hypothesis is that water vapour is escaping through a gap in the insulation over the kitchen and condensing on the underside of the felt, i.e. the cold side of the insulation.
My question for those more familiar with cold climates is, it is possible for several kgs of ice to build up in such a scenario? i.e. enough to melt on this sunny day and leak a few litres into the bucket?
