New extension adding more floor tiles

[Diyisfun]

Kitchen dinner 17ft x 17ft approx, I want an extension 17ft x 10ft approx, I am aware that I wont match the current floor tiles, whats the best way to lay new tiles & still look good. Current tiles are about 300 x 300mm
Or is it a case of you cant make it look good.

 

[tpt]

often you simply cant. I'd suggest retiling.

If you do be aware that the join in the two floors will need to be allowed for either by using an expansion joint or a decoupling mebrane or the tiles will crack along the line.