With seven-letter words being stacked from the middle in either direction until you get a 14×7 grid as demonstrated in the attached screenshot. How far is it possible to go until it becomes impossible to add more letters? (This diagram assumes that nobody has used their blank tiles yet.)
Using just the scrabble tiles and making valid words? And does it have to be done in turns, or do you mean laying it all out at once?
All in turns with valid plays.