Condensation in loft

You either need breathable or else plenty of eaves (and possibly ridge) ventilation.

Now't wrong with 'felt' provided there is plenty of other ventilation up there (mind you, I'm surprised they used felt on a 2005 re-roof.)

In essence, you need a good air flow up there to keep things dry.

What are your eaves like? Is there a plastic soffit? Does it have vent discs or a long grill in it?

Has loft insulation been pushed right into the corners thereby blocking off the air flow (probably the most common cause...)

 

No air vent at the gable end. Not sealed at undercloak to fascia on gable end. Possibilities.

Mr. HandyAndy - Really

 

Toffee, you will get condensation trying to form in your roof space, that's 'normal'. (It's usually from warm moist air coming up from the house below and condensing in the colder loft). The 'solution' for everyone is to have the loft ventilated enough to keep it dry.

If this problem is in a localised area, then it needs investigating for the specific cause, as Mr Ha says.

Where exactly along that gable is the condensation forming? Where are the nearest eaves vents to this. Any chance of some photos?

Are you saying that the condensation is forming on the actual felt, and then dripping down on to your ceiling?

A real shame the roofers didn't use breathable membrane - this would most likely have prevented this from happening. I doubt they were breaking any rules by using old-fashioned 'felt', but if their choice of materials is causing damage up there, then - in theory at least - they are liable.

But, 2005 was a fair time ago...

 

Did my roof in 2008, a few years after I know, and I used breathable felt from SF course. Maybe the builders were using up old stock?

Did they fit any special vent tiles, what tiles are in place now?