Grouting a Victorian Floor

[NWTiles]

don't use a dark colour, it will stain

Or use a dark colour and use bal protective sealer

 

[Time's Ran Out]

It could still frame the edges of the tiles through the joint grout. If your using one of the modern dust pressed tiles they accept moisture to a % so it's not worth the risk IMHO. Ardex C2 grey for me.