Translation:Are you going to be at your house tomorrow?
Is it me, or is there no interrogative inflection in this pronunciation at all?
Yes, estar does mean to be. But, the phrasal future tense is formed by using conjugation of "ir" and adding "a" + verb infinitive. (Yo) Voy a estar = I am going to be (or Am I going to be?) (Tù) Vas a estar = You are going to be (or Are you going to be?) (Él) Va a nadar = He is going to swim (or Is he going to swim?) (Nosotros) Vamos a dormir = We are going to sleep (or Are we...) (Ellas) Van a correr = They are going to run (or Are they going...)
[If you scroll down on the main page, this set of lessons has an explanation of the phrasal future tense.]