My house is 10 years old and for a while the plyboard panels in the loft above our en suite bathroom have been black. There has been a recurring problem whereby the venting hose connected to the extractor fan keeps coming off letting all the hot air loose in the loft. I was in the loft today and noticed the boards were quite damp to touch and when i ran my finger down them my finger was black. I noticed the venting hose had again become unattached from the fan and could well have been like this for a while. I checked the main bathroom fan too and this was the same. I have reattached the hoses and used brown parcel tape to secure them and hopefully stop this recurring but am worried about the damp black panels. Will they dry out ok or should i be getting a roofer in to look at them?