I don't know about anybody else but if your's has the specialty roof hatch that seals against roof like mine 09 bird's did, the best thing i found to do is switch it to a transpec hatch they fasten down to sheet metal and seal's against itself. i have had only a couple that i have had to reseal on my 10-12 year old buses, unlike the specialty hatch that came on all the 05 and up IC's and Bluebirds we have here, that i would say 90% leaked from day one. since 2010 i have spec'd the new buses with the transpec hatch and so far no leaks. both hatch's are one and the same company, so i was told but i prefer the transpec hatch. as for the roof seams there are many sealers out there that can be used. i have used Geobond fibered brushable roof seal purchased from TAC parts and also silcone based sealer from the bluebird dealer on seams. Next question is bus still covered under bird's body warranty 09 should be.
Take it to the dealer or someone Bluebird uses in your area for warranty. As slippert says it is probably the roof hatch. That "triple value" hatch is no value, LOL.
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