I'm trying to build a nice WF support. I'm new to game, and it looks like from ddowiki that repair spells (transmutation) finish at lvl 6 spells. What level Sorc do you need to be to cast lvl 6 spells?

I've seen other builds suggesting lvl 11 but I don't understand why/how caster spells work. Do you only need to Sorc lvl 6 to cast lvl 6 spells?