I have an odd scenario and hope to have a few different pieces of advice and the direction I should take. Two weeks ago water was getting into the ground unit of my 3 flat and I happen to live in this unit. It was under the carpet in a small hallway bridging the carpet and the tile attached next to it in the kitchen area from the living room. I ripped off that portion of the carpet to confirm it's a concrete slab underneath and no foundation cracks around there. The majority of it was in the middle of the carpet but the carpet was somewhat wet along one wall. I opened up the wall and an old chimney is there that is sealed. There's no water dripping from above so I believe all of it is inside the chimney and there's condensation on the outside of the chimney now up to about 2 ft up. There's none above that. I looked at the two units above and saw no issues anywhere on the drywall that's up against the chimney as it's not exposed on the top unit at all and the middle unit shows one side decoratively and looked fine.

Next step was to check the chimney. I replaced the roof last year as the inspector informed me the roof was on its last leg. I've attached a picture of the chimney flashing, which this roofer only used tar. He's licensed, bonded, and insured and had a lot of positive reviews and came from a referral. I contacted him after the water damage and his crew came out and installed metal flashing outside of the tar area at no charge. After looking into chimney flashing I'm not sure if this is appropriate and now I know that tar originally is not acceptable and prone to leaks. He claimed that if the issue was from the flashing the issue would be at the top unit and affect the drywall. He said that water inside the chimney could not result from improper flashing. Is that always the case? I'm wondering if his installation possibly has caused the leak and if he should be responsible for my damages?

I have a few chimney repair people coming in the next 2 weeks to assess the damages and help determine the cause but was hoping for some initial opinions as it's taking a few days before anyone can come out. Appreciate the advice!

The water damage area is extremely annoying as it's against the tile for the kitchen and carpet in the living room so I basically need to rip out the tile and carpet as I'm afraid there could be water under the tile. Would you agree that I need to rip out the tile to ensure there's no water based on that location? I'm debating about replacing it all with Lifeproof Luxury Vinyl in the off chance this occurs in the future as it'll be much easier to pull out a few boards and the vinyl would probably be a better look. Without formal estimates, I'm expecting around 4-5K to remove and replace for 600-700sq ft. This is in Chicago. Does this seem accurate? With a 2.5K deductible, it's not worth the call and hit on my insurance so this is an unexpected, annoying repair. I'm hoping the roofer would be liable and fall on him to cover the costs.