Our problem area is roofs with the older black sarking
felt as they don''t breathe.
Check the wall head and make sure the sarking
boards (underside of roof) are dry, as you might have a drip.
"I like working with recycled wood, and even use roofing sarking
, which has a lovely, rough texture.
Once the moisture is exposed to the cold underside of the sarking
felt under the slates or tiles it can only mean one thing - condensation.
It is also used for roofing as sarking
board and most likely forms your shed roof.
On older buildings which don't have sarking
felt beneath the slates, a peep into the loft space without a torch will tell you where the slate has come from, as daylight will shine through.
The result of all of this extra humidity is a blue/grey bloom develops on the underside of the sarking
felt and on the rafters.
Slate or tile roofs installed before the Second World War rarely had any sarking
felt beneath the slates or tiles.
The slow seeping leak was being caught by the underlining of sarking
felt, until last Friday when a full day of rain burst its way through and on to the bathroom ceiling.