Sarking felt repair

[Buzz word]

The other month I had a vendor pull out on a property I was buying so have been looking again. I found a house that I like and all is in good order that I can see appart from a concern I have with the roof. I would like to fit a sun tube to lighten the stairs so got up in the roof over the weekend.

What I found was some odd sarking felt. It is shiny on the inside like a thin foil. The other side is black and is decomposing. The main issue I have though is that in alot of places the felt is split right down the middle and you can see the light outside. I would estimate about 40% of the roof has blown felt.

I have done a bit of surfing about and spoken to a few people. It seems in some cases it has never been fitted since new in older places and isn't strictly necessary if the roof is ok and the pitch is sufficient. Is this right? I want to make an offer on the place as I like everything except this issue. It just concerns me that the only way I can see you can fix it would be to remove the tiles and with such a large amount damaged it would be a rather large job.

[blackcab]

Find a local registered NFRC roofer and ask them to have a look at it or give him the sizes over the phone and ask for a rough guide - roofing trade especially slate and tile is quiet at the moment so you can quality guys at mate down the pub prices