You'll probably find most the people on here that try to give advise are cowboy builders seaking advice and work them selves
I would suggest if your like me and confident enough to have a go then do a little more research, get a decent damp detector, a tarpoline and rope and have a go, worst case is you'll have to get the prof's in anyway and there's "nothing" out there that can't be fixed and you may save money in the long run as you will save labour costs by identifing the issue yourself.
However if you don't have the confidence then find a builder/roofer that doesn't mind you working along side to save money and pickup experiance, any proper tradesmen should be fine with it as they have nothing to hide
LOL
