in aprill last year we retiled a 1960s semi concrete tiles breathable felt(monarperm) refitted the 1 tile vent which was already in no problems all year no leaks or anything last week got call of leak went up in loft and underside of felt actually had icicles on it it was so wet all over we sugest another three tile vents two front and one more on back do you other roofers think this will help dont want to do it and it not fix the prob whats your thoughts (this is first serious condensation issue we have had)