I discussed this a while ago and @brian discussed it below. Basically you may need to wait up to ~40 hours for it to show up in Roon. The explanation is below.
A little disappointing but it is what it is. I have Audirvana and mConnect Player and a UPnP renderer for Friday/Saturday listening to new releases, while waiting for Tidal albums to show up in Roon.
I know the fantastic Roon Team are working hard to improve things though (where they can). Fingers crossed.