Wet saplings roof space very wet

More air flow is needed in the loft space ifit condensation I’d recommend fascia and soffit vents and dry ridge and hip system as recommended by the current British standard. This will make the loft nice and breezy keeping timbers dry taking any warm moist out the loft space.

without looking at the roof in question it is impossible to say why this is happening, your best bet is get a local roofer to have a look good luck Alex

Sounds like chronic condensatiln and sweating if all your timbers are wet . Check your felt membrane if its shiny grey / black polythene material with small reinforced squares showing with in the membrane then it will make no difference how much ventilating you put in its a srip job remove existing felt and replace .

Your insulation may be laid too far into the eaves blocking any air flow quite a common problem just pull the insulation away from the eave front and back. Try looking to see if your membrane is a old plastic membrane this causes untold amounts of condensation.