Water on felt in loft

[Michaelsf90]

I was in the process of feeding some cables up into my loft and I noticed white patches on the felt and water. I got told previously its condensation. Since then I have had roof tile vents installed

However since then we have also had new radiators fitted so the house in general is a lot warmer. I have uploaded some pics. Is it condensation and what is the white patches. Sorry if the pictures are a bit rubbish

 

[datarebal]

It is condensation .

You have new rads which mean more heat to carry moisture into the loft. upgrade the insulation, more venting and make sure the loft hatch is insulated and also that your bathroom extractors are properly fitted

 

[Michaelsf90]

What is the white stuff on the felt? The loft hatch is a culprit as it doesnt sit properly. I was going to put some insulation on the top of it, then put a cut rubble bag over and tape it on. Then once I can make it fit use some draught protection stuff to kind of like make a seal. Either that or make a new loft hatch myself from wood and as you said insulate it over the top