I've noticed the north facing side of my house roof has water dripping from the insulation/roof felt in the loft. House was built pre-1970 and doesn't appear to have any vents in the roof, but in the loft there's gaps between some of the insulation on the inside of the rafters (see pictures). Is this normal and just a build up of condensation?
I have the same problem. It's normal to an extent - i.e. given the colder weather we have had lately. I think it's because the warm air in the house is hitting the cold roof and condensing. This is particularly in issue if you have added insulation and have double glazing without trickle vents or with the vents closed. I have installed some felt vents which sit in the overlaps to get a bit of airflow. It has helped the worst area above the bathroom, but seems to have shifted the problem along!
You have insulation with no vapour barrier to prevent the water vapour reaching the cold side of the insulation, this is a strange way to insulate a loft. To stop the condensation, fit a vapour barrier on the warm side of the insulation, ensure adequate ventilation above.
I've bought some felt/lap vents and will give them a try. Read that they need to installed on both sides of the roof and not opposite each other, so that the air can flow from one side to the other. Hopefully they help.