Need to some tiles on my roof.?

Professional here, are you talking about Slate tiles, Spanish tiles, or shingles ??? Flashing around vents requires a pointing trowel with the end tip broken off, makes it easier to apply around flashing, I would use Karnak brand myself, have used it 20 yrs commercially. You would require skill to get this right even if you try. Replacing any so called Tiles also requires experience, if you never walked a roof, you could kill yourself. If your in the NYC area. email me, I'll either tell you how to do this yourself or do it for you for a charge.

the tricky part to working on a tile roof is staying on it. and not cracking any additional tiles. usually when i repair a tile roof i set up scaffolding there are a bunch of reasonss . the tiles sre heavy and hard to handle on just a ladder, the scaffolding offers a nice work area, and most important its alot safer, you can go to any rental store and rent scaffolding, when resealing around flashing and vents use a rubber butyl caulk for longer durability