Loft Insulation

[YNWA]

Can I insulate my roof joists to reduce condensation problems,my loft flooring already has has basic insulation,4",and the centre section has been been boarded so I don't really want to lift the boards,I would like to fit insulation between the roof joists and then cover with plaster board but I have been told this can bring more problems,I went into my loft today and there were long rows of water on the floor which had fallen from the roofing felt overhead,the water problem is worse on one side of the house than the other,my property is a 4 bed detached.
I believe the recommended thickness of insulation is approx' 11"

 

[masona]

Is the roof ventilated? eg: soffit vent etc

 

[YNWA]

Hi,Yes,The soffits are ventilated,vents were fitted at regular spaces when I had new PVC ones fitted.

 

[shenks]

Do you have a non-condensing dryer in the house for your washing? Or maybe a humidifier/aircon running on overdrive? These types of things would worsen any condensation problem even with good roof space ventilation.

Just one other thought, is your insulation between the joists tight to the wallplate? If so then this may be a factor as there should always be a space.

Alternatively is it possible you just have a hidden leak in your roof that is causing the pooling? Is it worse after it has rained?

 

[YNWA]

Hi,Thank you all for your comments,None of the conditions last mentioned apply to my problem and there is no leak,the water found lies directly beneath drips found on my roof lining,it is definately condensation,I need suggestions on how to reduce this,I thought by insulating my roof joists this could help,my floor joists are already insulated and partly sheeted.If I insulate my roof joists will this give me further problems ?