After some advice please.Recently I had someone offer to install foam insulation in attic.Did my research and dismissed it.During the inspection he carried out he said I have servere wet rot in my timber in the attic.Did his moister test ranged from 14 to 17% in the wood.The timbers to me fell bone dry and no rot anywhere.The main reason for this appeal for advice is that I have noticed alot of what seems to be grey powder on the beams.Some of it it hard bit like mortar.Comes of easy.The wood underneath is fine.Having the attic floor top up with insulation next Tuesday.The old insulation has been there since I've been in the house 1998 and on moving some noticed similar small pieces of this grey stuff under the old insulation.Any ideas what am dealing with here.Think the house was built late 30s.
Watch this for some information. However plenty of rock wool then you need air flow blowing through loft space. Vent either end to get air blowing through loft space. Or put vents in soffits.
Attic seems,well vented.Man coming to lay new insulation. I've ask him to check vents aren't blocked.Also ordered some lap vents.
Thanks.Seen that vid.New lnsulation coming Monday to top up old as only about 150mm thick.Have a theroy that the grey stuff mabe some form of mortar powder and has harden due to condisation. No leaks in roof,wood not damp.had cardboard boxs up there they are bone dry.Will keep a close eye one new insulation down and some flap vents slipped in.