jonboy

My understanding is that your house insurance covers you for up to two million

As a roofer with 20 years experience, I've never heard of flexotweal, so unless it is something French I'd give it a miss. Personally I'd replace the broken tile and see what happens, if it doesn't leak you've got a winner. Jonboy

Hi Nick, the centre of the rafters should be no more than 600 mm apart, but this could be less depending on the dimentions of the rafter. The gap between the battens totally depends on type and size of material being used

Roofing felt's main purpose is to counteract condensation. The main cause of condensation is central heating. You can now get breathable felts which are not tar based (in fact the French invented them with Tyvec), these are semi expensive but worthwhile as they negate the need for other (often more expensive) ways of ventilating a roof. Hope this helps.